Fix boolean all reduce bug (#1355)

* Chore: update pre-commit refs

* run pre-commit

.circleci/config.yml

@@ -1,5 +1,8 @@
 version: 2.1
 
+orbs:
+  apple: ml-explore/pr-approval@0.1.0
+
 parameters:
   nightly_build:
     type: boolean
@@ -7,6 +10,9 @@ parameters:
   weekly_build:
     type: boolean
     default: false
+  test_release:
+    type: boolean
+    default: false
 
 jobs:
   linux_build_and_test:
@@ -25,8 +31,7 @@ jobs:
           name: Install dependencies
           command: |
             pip install --upgrade cmake
-            pip install --upgrade pybind11[global]
-            pip install pybind11-stubgen
+            pip install nanobind==2.1.0
             pip install numpy
             sudo apt-get update
             sudo apt-get install libblas-dev liblapack-dev liblapacke-dev
@@ -38,16 +43,13 @@ jobs:
       - run:
           name: Generate package stubs
           command: |
-            python3 setup.py generate_stubs
+            echo "stubs"
+            pip install typing_extensions
+            python setup.py generate_stubs 
       - run:
           name: Run Python tests
           command: |
             python3 -m unittest discover python/tests -v
-      # TODO: Reenable when extension api becomes stable
-      # - run:
-      #     name: Build example extension
-      #     command: |
-      #       cd examples/extensions && python3 -m pip install . 
       - run:
           name: Build CPP only
           command: |
@@ -57,20 +59,25 @@ jobs:
           command: ./build/tests/tests
 
   mac_build_and_test:
-    machine: true
-    resource_class: ml-explore/m-builder
+    parameters:
+      xcode_version:
+        type: string
+        default: "15.2.0"
+    macos:
+      xcode: << parameters.xcode_version >>
+    resource_class: macos.m1.medium.gen1
     steps:
       - checkout
       - run:
           name: Install dependencies
           command: |
-            eval "$(conda shell.bash hook)"
-            rm -r $CONDA_PREFIX/envs/runner-env
-            conda create -y -n runner-env python=3.9
-            conda activate runner-env
+            brew install python@3.8
+            brew install openmpi
+            python3.8 -m venv env
+            source env/bin/activate
+            pip install --upgrade pip
             pip install --upgrade cmake
-            pip install --upgrade pybind11[global]
-            pip install pybind11-stubgen
+            pip install nanobind==2.1.0
             pip install numpy
             pip install torch
             pip install tensorflow
@@ -78,203 +85,180 @@ jobs:
       - run:
           name: Install Python package
           command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            CMAKE_BUILD_PARALLEL_LEVEL="" python setup.py build_ext --inplace
-            CMAKE_BUILD_PARALLEL_LEVEL="" python setup.py develop
+            source env/bin/activate
+            CMAKE_BUILD_PARALLEL_LEVEL="" pip install -e . -v
       - run:
           name: Generate package stubs
           command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            python setup.py generate_stubs
+            source env/bin/activate
+            pip install typing_extensions
+            python setup.py generate_stubs 
       - run:
           name: Run Python tests
           command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            DEVICE=cpu python -m xmlrunner discover -v python/tests -o test-results/cpu
-            DEVICE=gpu python -m xmlrunner discover -v python/tests -o test-results/gpu
-      # TODO: Reenable when extension api becomes stable
-      # - run:
-      #     name: Build example extension
-      #     command: |
-      #       eval "$(conda shell.bash hook)"
-      #       conda activate runner-env
-      #       cd examples/extensions && python -m pip install . 
+            source env/bin/activate
+            LOW_MEMORY=1 DEVICE=cpu python -m xmlrunner discover -v python/tests -o test-results/cpu
+            LOW_MEMORY=1 DEVICE=gpu METAL_DEVICE_WRAPPER_TYPE=1 METAL_DEBUG_ERROR_MODE=0 python -m xmlrunner discover -v python/tests -o test-results/gpu
+            mpirun -host localhost:8 -np 8 -x DYLD_LIBRARY_PATH=/opt/homebrew/lib/ python python/tests/mpi_test_distributed.py
+      - run:
+          name: Build example extension
+          command: |
+            source env/bin/activate
+            cd examples/extensions
+            pip install -r requirements.txt
+            python setup.py build_ext -j8
       - store_test_results:
           path: test-results
       - run:
           name: Build CPP only
           command: |
+            source env/bin/activate
             mkdir -p build && cd build && cmake .. && make -j
       - run:
           name: Run CPP tests
-          command: METAL_DEVICE_WRAPPER_TYPE=1 METAL_DEBUG_ERROR_MODE=0 ./build/tests/tests
+          command: |
+            DEVICE=gpu METAL_DEVICE_WRAPPER_TYPE=1 METAL_DEBUG_ERROR_MODE=0 ./build/tests/tests
+      - run:
+          name: Build small binary
+          command: |
+            source env/bin/activate
+            cd build/
+            cmake .. -DCMAKE_BUILD_TYPE=MinSizeRel -DBUILD_SHARED_LIBS=ON -DMLX_BUILD_CPU=OFF -DMLX_BUILD_SAFETENSORS=OFF -DMLX_BUILD_GGUF=OFF -DMLX_METAL_JIT=ON
+            make -j
 
   build_release:
-    machine: true
-    resource_class: ml-explore/m-builder
     parameters:
       python_version:
         type: string
         default: "3.9"
-      macos_version:
+      xcode_version:
         type: string
-        default: "14"
+        default: "15.2.0"
+      build_env:
+        type: string
+        default: ""
+    macos:
+      xcode: << parameters.xcode_version >>
+    resource_class: macos.m1.medium.gen1
     steps:
       - checkout
       - run:
           name: Install dependencies
           command: |
-            eval "$(conda shell.bash hook)"
-            rm -r $CONDA_PREFIX/envs/runner-env
-            conda create -y -n runner-env python=<< parameters.python_version >>
-            conda activate runner-env
+            brew install python@<< parameters.python_version >>
+            brew install openmpi
+            python<< parameters.python_version >> -m venv env
+            source env/bin/activate
+            pip install --upgrade pip
             pip install --upgrade cmake
-            pip install --upgrade pybind11[global]
-            pip install pybind11-stubgen
+            pip install nanobind==2.1.0
+            pip install --upgrade setuptools
             pip install numpy
             pip install twine
-      # TODO: Update build system to switch away from setup.py develop
+            pip install build
       - run:
           name: Install Python package
           command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            DEVELOPER_DIR=$(developer_dir_macos_<< parameters.macos_version >>) \
-              PYPI_RELEASE=1 \
+            source env/bin/activate
+            DEV_RELEASE=1 \
               CMAKE_BUILD_PARALLEL_LEVEL="" \
-              python setup.py develop
+              pip install . -v
       - run:
           name: Generate package stubs
           command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            python setup.py generate_stubs
+            source env/bin/activate
+            pip install typing_extensions
+            python setup.py generate_stubs 
       - run:
-          name: Publish Python package
+          name: Build Python package
           command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            DEVELOPER_DIR=$(developer_dir_macos_<< parameters.macos_version >>) \
-              PYPI_RELEASE=1 \
+            source env/bin/activate
+            << parameters.build_env >> \
               CMAKE_BUILD_PARALLEL_LEVEL="" \
-              python setup.py bdist_wheel
-            twine upload dist/* --repository mlx
+              python -m build -w
+      - when:
+          condition: << parameters.build_env >>
+          steps:
+            - run:
+                name: Upload package
+                command: |
+                  source env/bin/activate
+                  twine upload dist/*
       - store_artifacts:
           path: dist/
 
-  build_dev_release:
-    machine: true
-    resource_class: ml-explore/m-builder
+  build_linux_test_release:
     parameters:
       python_version:
         type: string
         default: "3.9"
-      macos_version:
+      extra_env:
         type: string
-        default: "14"
+        default: "DEV_RELEASE=1"
+    docker:
+      - image: ubuntu:20.04
     steps:
       - checkout
       - run:
-          name: Install dependencies
+          name: Build wheel
           command: |
-            eval "$(conda shell.bash hook)"
-            rm -r $CONDA_PREFIX/envs/runner-env
-            conda create -y -n runner-env python=<< parameters.python_version >>
-            conda activate runner-env
+            PYTHON=python<< parameters.python_version >>
+            apt-get update
+            apt-get upgrade -y
+            DEBIAN_FRONTEND=noninteractive TZ=Etc/UTC apt-get -y install tzdata
+            apt-get install -y apt-utils
+            apt-get install -y software-properties-common
+            add-apt-repository -y ppa:deadsnakes/ppa
+            apt-get install -y $PYTHON $PYTHON-dev $PYTHON-full
+            apt-get install -y libblas-dev liblapack-dev liblapacke-dev
+            apt-get install -y build-essential git
+            $PYTHON -m venv env
+            source env/bin/activate
+            pip install --upgrade pip
             pip install --upgrade cmake
-            pip install --upgrade pybind11[global]
-            pip install pybind11-stubgen
+            pip install nanobind==2.1.0
+            pip install --upgrade setuptools
             pip install numpy
-            pip install twine
-      - run:
-          name: Install Python package
-          command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            DEVELOPER_DIR=$(developer_dir_macos_<< parameters.macos_version >>) \
-              DEV_RELEASE=1 \
+            pip install auditwheel
+            pip install patchelf
+            pip install build
+            << parameters.extra_env >> \
               CMAKE_BUILD_PARALLEL_LEVEL="" \
-              python setup.py develop
-      - run:
-          name: Generate package stubs
-          command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            python setup.py generate_stubs
-      - run:
-          name: Publish Python package
-          command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            DEVELOPER_DIR=$(developer_dir_macos_<< parameters.macos_version >>) \
-              DEV_RELEASE=1 \
+              pip install . -v
+            pip install typing_extensions
+            python setup.py generate_stubs 
+            << parameters.extra_env >> \
               CMAKE_BUILD_PARALLEL_LEVEL="" \
-              python setup.py bdist_wheel
-            twine upload dist/* --repository mlx
+              python -m build --wheel
+            auditwheel show dist/*
+            auditwheel repair dist/* --plat manylinux_2_31_x86_64
       - store_artifacts:
-          path: dist/
-
-  build_package:
-    machine: true
-    resource_class: ml-explore/m-builder
-    parameters:
-      python_version:
-        type: string
-        default: "3.9"
-      macos_version:
-        type: string
-        default: "14"
-    steps:
-      - checkout
-      - run:
-          name: Install dependencies
-          command: |
-            eval "$(conda shell.bash hook)"
-            rm -r $CONDA_PREFIX/envs/runner-env
-            conda create -y -n runner-env python=<< parameters.python_version >>
-            conda activate runner-env
-            pip install --upgrade cmake
-            pip install --upgrade pybind11[global]
-            pip install pybind11-stubgen
-            pip install numpy
-            pip install twine
-      - run:
-          name: Install Python package
-          command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            DEVELOPER_DIR=$(developer_dir_macos_<< parameters.macos_version >>) \
-              CMAKE_BUILD_PARALLEL_LEVEL="" \
-              python setup.py develop
-      - run:
-          name: Generate package stubs
-          command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            python setup.py generate_stubs
-      - run:
-          name: Build package distribution
-          command: |
-            eval "$(conda shell.bash hook)"
-            conda activate runner-env
-            DEVELOPER_DIR=$(developer_dir_macos_<< parameters.macos_version >>) \
-              CMAKE_BUILD_PARALLEL_LEVEL="" \
-              python setup.py bdist_wheel
-      - store_artifacts:
-          path: dist/
+          path: wheelhouse/
 
 workflows:
   build_and_test:
     when:
       and:
+        - matches:
+            pattern: "^(?!pull/)[-\\w]+$"
+            value: << pipeline.git.branch >>
         - not: << pipeline.parameters.nightly_build >>
         - not: << pipeline.parameters.weekly_build >>
+        - not: << pipeline.parameters.test_release >>
     jobs:
+      - mac_build_and_test:
+          matrix:
+            parameters:
+              xcode_version: ["15.0.0", "15.2.0"]
       - linux_build_and_test
-      - mac_build_and_test
+
+  build_pypi_release:
+    when:
+      and:
+        - not: << pipeline.parameters.nightly_build >>
+        - not: << pipeline.parameters.weekly_build >>
+        - not: << pipeline.parameters.test_release >>
+    jobs:
       - build_release:
           filters:
             tags:
@@ -284,20 +268,56 @@ workflows:
           matrix:
             parameters:
               python_version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
-              macos_version: ["13", "14"]
+              xcode_version: ["15.0.0", "15.2.0"]
+              build_env: ["PYPI_RELEASE=1"]
+  prb:
+    when:
+      matches:
+        pattern: "^pull/\\d+(/head)?$"
+        value: << pipeline.git.branch >>
+    jobs:
+      - hold:
+          type: approval
+      - apple/authenticate:
+          context: pr-approval
+      - mac_build_and_test:
+          requires: [ hold ]
+          matrix:
+            parameters:
+              xcode_version: ["15.0.0", "15.2.0"]
+      - linux_build_and_test:
+          requires: [ hold ]
   nightly_build:
-    when: << pipeline.parameters.nightly_build >>
+    when:
+      and:
+        - equal: [ main, << pipeline.git.branch >> ]
+        - << pipeline.parameters.nightly_build >>
     jobs:
-      - build_package:
+      - build_release:
           matrix:
             parameters:
               python_version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
-              macos_version: ["13", "14"]
+              xcode_version: ["15.0.0", "15.2.0"]
   weekly_build:
-    when: << pipeline.parameters.weekly_build >>
+    when:
+      and:
+        - equal: [ main, << pipeline.git.branch >> ]
+        - << pipeline.parameters.weekly_build >>
     jobs:
-      - build_dev_release:
+      - build_release:
           matrix:
             parameters:
               python_version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
-              macos_version: ["13", "14"]
+              xcode_version: ["15.0.0", "15.2.0"]
+              build_env: ["DEV_RELEASE=1"]
+  linux_test_release:
+    when:
+      and:
+        - equal: [ main, << pipeline.git.branch >> ]
+        - << pipeline.parameters.test_release >>
+    jobs:
+      - build_linux_test_release:
+          matrix:
+            parameters:
+              python_version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+              extra_env: ["PYPI_RELEASE=1"]

.github/workflows/pull_request.yml

@@ -17,4 +17,4 @@ jobs:
           pip install pre-commit black isort clang-format
       - name: Run lint
         run: |
-          pre-commit run --all-files
+          pre-commit run --all-files

.pre-commit-config.yaml

@@ -1,11 +1,11 @@
 repos:
 -   repo: https://github.com/pre-commit/mirrors-clang-format
-    rev: v17.0.6
+    rev: v18.1.8
     hooks:
     -   id: clang-format
 # Using this mirror lets us use mypyc-compiled black, which is about 2x faster
 -   repo: https://github.com/psf/black-pre-commit-mirror
-    rev: 23.12.1
+    rev: 24.8.0
     hooks:
     -   id: black
 -   repo: https://github.com/pycqa/isort

ACKNOWLEDGMENTS.md

@@ -7,11 +7,17 @@ with a short description of your contribution(s) below. For example:
 
 MLX was developed with contributions from the following individuals:
 
-- Nripesh Niketan: Added `softsign`, `softmax`, `hardswish`, `logsoftmax` activation functions. Added `dropout3d` ops. Added `LogicalAnd` and `LogicalOR` ops.
+- Nripesh Niketan: Added `softsign`, `softmax`, `hardswish`, `logsoftmax` activation functions. Added `dropout3d` ops. Added `LogicalAnd` and `LogicalOR` ops. Added `clip_grad_norm` along with `tree_reduce`.
 - Juarez Bochi: Fixed bug in cross attention.
 - Justin Deschenaux: Sine, Cosine, arange, randint, truncated normal, bernoulli, lion optimizer, Dropout2d, linear and logistic regression python example.
-- Diogo Da Cruz: Added `tri`, `tril`, `triu`, `tensordot`, `inner`, `outer`, `tile` and safetensor support
-- Gabrijel Boduljak: Added `mlx.core.linalg`, implemented `norm` method and `InstanceNorm` layer.
+- Diogo Da Cruz: Added `tri`, `tril`, `triu`, `tensordot`, `inner`, `outer`, `tile`, `StreamContext`, `stream`, safetensors support, `einsum`, and `einsum_path`.
+- Gabrijel Boduljak: Added `mlx.core.linalg`, implemented `norm` method and `InstanceNorm` layer. Implemented pooling layers and ``Upsample``.
+- Hinrik Snær Guðmundsson: Added `atleast_1d`, `atleast_2d`, `atleast_3d` ops.
+- Luca Arnaboldi: Added `Ceil` and `Floor` ops; implemented pickling, copy and deepcopy for mlx arrays.
+- Brian Keene & Atila Orhon, with Argmax Inc.: Added `fast.scaled_dot_product_attention`
+- AmirHossein Razlighi: Added chaining support for some of the ops in `nn.Module`. Comparison works for non array objects in `mlx.core.array`. Exception handling for invalid operations in `mlx.core.array`.
+- Gleb Pobudzey: Added the `where` primitive, and groups in 1D and 2D convolutions.
+- Paul Paczuski: Improved stability of BCE loss calculation
 
 <a href="https://github.com/ml-explore/mlx/graphs/contributors">
   <img class="dark-light" src="https://contrib.rocks/image?repo=ml-explore/mlx&anon=0&columns=20&max=100&r=true" />
@@ -252,4 +258,4 @@ Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
-limitations under the License.
+limitations under the License.

CMakeLists.txt

@@ -15,32 +15,37 @@ option(MLX_BUILD_EXAMPLES "Build examples for mlx" ON)
 option(MLX_BUILD_BENCHMARKS "Build benchmarks for mlx" OFF)
 option(MLX_BUILD_PYTHON_BINDINGS "Build python bindings for mlx" OFF)
 option(MLX_BUILD_METAL "Build metal backend" ON)
+option(MLX_BUILD_CPU "Build cpu backend" ON)
+option(MLX_METAL_DEBUG "Enhance metal debug workflow" OFF)
+option(MLX_ENABLE_X64_MAC "Enable building for x64 macOS" OFF)
+option(MLX_BUILD_GGUF "Include support for GGUF format" ON)
+option(MLX_BUILD_SAFETENSORS "Include support for safetensors format" ON)
+option(MLX_METAL_JIT "Use JIT compilation for Metal kernels" OFF)
 option(BUILD_SHARED_LIBS "Build mlx as a shared library" OFF)
 
 if(NOT MLX_VERSION)
-  set(MLX_VERSION 0.1.0)
+  set(MLX_VERSION 0.17.1)
 endif()
 
 # --------------------- Processor tests -------------------------
 
-message(STATUS "Building MLX for ${CMAKE_HOST_SYSTEM_PROCESSOR} processor on ${CMAKE_SYSTEM_NAME}")
+message(STATUS "Building MLX for ${CMAKE_SYSTEM_PROCESSOR} processor on ${CMAKE_SYSTEM_NAME}")
 
 set(MLX_BUILD_ARM OFF)
 
 if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
-
-  if (${CMAKE_HOST_SYSTEM_PROCESSOR} MATCHES "x86_64" AND ${CMAKE_HOST_APPLE})
-    message(FATAL_ERROR
-      "Building for x86_64 on macOS is not supported."
-      " If you are on an Apple silicon system, check the build"
-      " documentation for possible fixes: "
-      "https://ml-explore.github.io/mlx/build/html/install.html#build-from-source")
-  elseif (${CMAKE_HOST_SYSTEM_PROCESSOR} MATCHES "x86_64")
-    message(WARNING
-      "Building for x86_64 on macOS is not supported."
-      " If you are on an Apple silicon system, "
-      " make sure you are building for arm64.")
-  elseif(${CMAKE_HOST_SYSTEM_PROCESSOR} MATCHES "arm64")
+  if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "x86_64")
+    if(NOT MLX_ENABLE_X64_MAC)
+      message(FATAL_ERROR
+        "Building for x86_64 on macOS is not supported."
+        " If you are on an Apple silicon system, check the build"
+        " documentation for possible fixes: "
+        "https://ml-explore.github.io/mlx/build/html/install.html#build-from-source")
+    else()
+      message(WARNING "Building for x86_64 arch is not officially supported.")
+    endif()
+    set(MLX_BUILD_METAL OFF)
+  elseif(${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm64")
     set(MLX_BUILD_ARM ON)
   endif()
 
@@ -65,26 +70,30 @@ endif()
 if (MLX_BUILD_METAL AND NOT METAL_LIB)
   message(STATUS "Metal not found. Unable to build GPU")
   set(MLX_BUILD_METAL OFF)
+  set(MLX_METAL_DEBUG OFF)
 elseif (MLX_BUILD_METAL)
   message(STATUS "Building METAL sources")
-  add_compile_definitions(_METAL_)
+
+  if (MLX_METAL_DEBUG)
+    add_compile_definitions(MLX_METAL_DEBUG)
+  endif()
 
   # Throw an error if xcrun not found
   execute_process(COMMAND zsh "-c" "/usr/bin/xcrun -sdk macosx --show-sdk-version"
                   OUTPUT_VARIABLE MACOS_VERSION
                   COMMAND_ERROR_IS_FATAL ANY)
 
+  if (${MACOS_VERSION} LESS 14.0)
+    message(FATAL_ERROR "MLX requires macOS SDK >= 14.0 to be built with MLX_BUILD_METAL=ON" )
+  endif()
   message(STATUS "Building with SDK for macOS version ${MACOS_VERSION}")
 
-  if (${MACOS_VERSION} GREATER_EQUAL 14.2)
-    set(METAL_CPP_URL https://developer.apple.com/metal/cpp/files/metal-cpp_macOS14.2_iOS17.2.zip)
-  elseif (${MACOS_VERSION} GREATER_EQUAL 14.0)
-    set(METAL_CPP_URL https://developer.apple.com/metal/cpp/files/metal-cpp_macOS14_iOS17-beta.zip)
-  elseif (${MACOS_VERSION} GREATER_EQUAL 13.3)
-    set(METAL_CPP_URL https://developer.apple.com/metal/cpp/files/metal-cpp_macOS13.3_iOS16.4.zip)
-  else()
-    message(FATAL_ERROR "MLX requires macOS >= 13.4 to be built with MLX_BUILD_METAL=ON" )
-  endif()
+  set(METAL_CPP_URL https://developer.apple.com/metal/cpp/files/metal-cpp_macOS15_iOS18-beta.zip)
+  # Get the metal version
+  execute_process(
+    COMMAND zsh "-c" "echo \"__METAL_VERSION__\" | xcrun -sdk macosx metal -E -x metal -P - | tail -1 | tr -d '\n'"
+    OUTPUT_VARIABLE MLX_METAL_VERSION
+    COMMAND_ERROR_IS_FATAL ANY)
 
   FetchContent_Declare(
     metal_cpp
@@ -98,46 +107,85 @@ elseif (MLX_BUILD_METAL)
     $<INSTALL_INTERFACE:include/metal_cpp>
   )
   target_link_libraries(
-    mlx
+    mlx PUBLIC
     ${METAL_LIB}
     ${FOUNDATION_LIB}
     ${QUARTZ_LIB})
+
+  add_compile_definitions("MLX_METAL_VERSION=${MLX_METAL_VERSION}")
 endif()
 
-find_library(ACCELERATE_LIBRARY Accelerate)
-if (MLX_BUILD_ARM AND ACCELERATE_LIBRARY)
-  message(STATUS "Accelerate found ${ACCELERATE_LIBRARY}")
-  set(MLX_BUILD_ACCELERATE ON)
-  target_link_libraries(mlx ${ACCELERATE_LIBRARY})
-  add_compile_definitions(ACCELERATE_NEW_LAPACK)
-else()
-  message(STATUS "Accelerate or arm neon not found, using default backend.")
-  set(MLX_BUILD_ACCELERATE OFF)
-  #set(BLA_VENDOR Generic)
-  find_package(BLAS REQUIRED)
-  if (NOT BLAS_FOUND)
-    message(FATAL_ERROR "Must have BLAS installed")
-  endif()
-  # TODO find a cleaner way to do this
-  find_path(BLAS_INCLUDE_DIRS cblas.h
-    /usr/include
-    /usr/local/include
-    $ENV{BLAS_HOME}/include)
-  message(STATUS "Blas lib" ${BLAS_LIBRARIES})
-  message(STATUS "Blas incclude" ${BLAS_INCLUDE_DIRS})
-  target_include_directories(mlx PRIVATE ${BLAS_INCLUDE_DIRS})
-  target_link_libraries(mlx ${BLAS_LIBRARIES})
-  find_package(LAPACK REQUIRED)
-  if (NOT LAPACK_FOUND)
+if (MLX_BUILD_CPU)
+  find_library(ACCELERATE_LIBRARY Accelerate)
+  if (MLX_BUILD_ARM AND ACCELERATE_LIBRARY)
+    message(STATUS "Accelerate found ${ACCELERATE_LIBRARY}")
+    set(MLX_BUILD_ACCELERATE ON)
+    target_link_libraries(mlx PUBLIC ${ACCELERATE_LIBRARY})
+    add_compile_definitions(ACCELERATE_NEW_LAPACK)
+  else()
+    message(STATUS "Accelerate or arm neon not found, using default backend.")
+    set(MLX_BUILD_ACCELERATE OFF)
+    if(${CMAKE_HOST_APPLE})
+      # The blas shipped in macOS SDK is not supported, search homebrew for
+      # openblas instead.
+      set(BLA_VENDOR OpenBLAS)
+      set(LAPACK_ROOT "${LAPACK_ROOT};$ENV{LAPACK_ROOT};/usr/local/opt/openblas")
+    endif()
+    # Search and link with lapack.
+    find_package(LAPACK REQUIRED)
+    if (NOT LAPACK_FOUND)
       message(FATAL_ERROR "Must have LAPACK installed")
+    endif()
+    find_path(LAPACK_INCLUDE_DIRS lapacke.h
+      /usr/include
+      /usr/local/include
+      /usr/local/opt/openblas/include)
+    message(STATUS "Lapack lib " ${LAPACK_LIBRARIES})
+    message(STATUS "Lapack include " ${LAPACK_INCLUDE_DIRS})
+    target_include_directories(mlx PRIVATE ${LAPACK_INCLUDE_DIRS})
+    target_link_libraries(mlx PUBLIC ${LAPACK_LIBRARIES})
+    # List blas after lapack otherwise we may accidentally incldue an old version
+    # of lapack.h from the include dirs of blas.
+    find_package(BLAS REQUIRED)
+    if (NOT BLAS_FOUND)
+      message(FATAL_ERROR "Must have BLAS installed")
+    endif()
+    # TODO find a cleaner way to do this
+    find_path(BLAS_INCLUDE_DIRS cblas.h
+      /usr/include
+      /usr/local/include
+      $ENV{BLAS_HOME}/include)
+    message(STATUS "Blas lib " ${BLAS_LIBRARIES})
+    message(STATUS "Blas include " ${BLAS_INCLUDE_DIRS})
+    target_include_directories(mlx PRIVATE ${BLAS_INCLUDE_DIRS})
+    target_link_libraries(mlx PUBLIC ${BLAS_LIBRARIES})
   endif()
-  find_path(LAPACK_INCLUDE_DIRS lapacke.h
-    /usr/include
-    /usr/local/include)
-  message(STATUS "Lapack lib" ${LAPACK_LIBRARIES})
-  message(STATUS "Lapack include " ${LAPACK_INCLUDE_DIRS})
-  target_include_directories(mlx PRIVATE ${LAPACK_INCLUDE_DIRS})
-  target_link_libraries(mlx ${LAPACK_LIBRARIES})
+else()
+  set(MLX_BUILD_ACCELERATE OFF)
+endif()
+
+find_package(MPI)
+if (MPI_FOUND)
+  execute_process(
+    COMMAND zsh "-c" "mpirun --version"
+    OUTPUT_VARIABLE MPI_VERSION
+    ERROR_QUIET
+  )
+  if (${MPI_VERSION} MATCHES ".*Open MPI.*")
+    target_include_directories(mlx PRIVATE ${MPI_INCLUDE_PATH})
+  elseif (MPI_VERSION STREQUAL "")
+    set(MPI_FOUND FALSE)
+    message(
+      WARNING
+      "MPI found but mpirun is not available. Building without MPI."
+    )
+  else()
+    set(MPI_FOUND FALSE)
+    message(
+      WARNING
+      "MPI which is not OpenMPI found. Building without MPI."
+    )
+  endif() 
 endif()
 
 add_subdirectory(${CMAKE_CURRENT_LIST_DIR}/mlx)
@@ -149,10 +197,22 @@ target_include_directories(
   $<INSTALL_INTERFACE:include>
 )
 
+FetchContent_Declare(fmt
+  GIT_REPOSITORY https://github.com/fmtlib/fmt.git
+  GIT_TAG 10.2.1 
+  EXCLUDE_FROM_ALL
+)
+FetchContent_MakeAvailable(fmt)
+target_link_libraries(mlx PRIVATE fmt::fmt-header-only)
+
 if (MLX_BUILD_PYTHON_BINDINGS)
   message(STATUS "Building Python bindings.")
-  find_package(Python COMPONENTS Interpreter Development)
-  find_package(pybind11 CONFIG REQUIRED)
+  find_package(Python 3.8 COMPONENTS Interpreter Development.Module REQUIRED)
+  execute_process(
+    COMMAND "${Python_EXECUTABLE}" -m nanobind --cmake_dir
+    OUTPUT_STRIP_TRAILING_WHITESPACE OUTPUT_VARIABLE NB_DIR)
+  list(APPEND CMAKE_PREFIX_PATH "${NB_DIR}")
+  find_package(nanobind CONFIG REQUIRED)
   add_subdirectory(${CMAKE_CURRENT_LIST_DIR}/python/src)
 endif()
 

MANIFEST.in

@@ -1,4 +1,4 @@
 include CMakeLists.txt
 recursive-include mlx/ *
 include python/src/*
-python/mlx/py.typed # support type hinting as in PEP-561
+include python/mlx/py.typed # support type hinting as in PEP-561

README.md

@@ -6,15 +6,17 @@
 
 [![CircleCI](https://circleci.com/gh/ml-explore/mlx.svg?style=svg)](https://circleci.com/gh/ml-explore/mlx)
 
-MLX is an array framework for machine learning on Apple silicon, brought to you
-by Apple machine learning research.
+MLX is an array framework for machine learning research on Apple silicon,
+brought to you by Apple machine learning research.
 
 Some key features of MLX include:
 
- - **Familiar APIs**: MLX has a Python API that closely follows NumPy.
-   MLX also has a fully featured C++ API, which closely mirrors the Python API. 
-   MLX has higher-level packages like `mlx.nn` and `mlx.optimizers` with APIs
-   that closely follow PyTorch to simplify building more complex models.
+ - **Familiar APIs**: MLX has a Python API that closely follows NumPy.  MLX
+   also has fully featured C++, [C](https://github.com/ml-explore/mlx-c), and
+   [Swift](https://github.com/ml-explore/mlx-swift/) APIs, which closely mirror
+   the Python API.  MLX has higher-level packages like `mlx.nn` and
+   `mlx.optimizers` with APIs that closely follow PyTorch to simplify building
+   more complex models.
 
  - **Composable function transformations**: MLX supports composable function
    transformations for automatic differentiation, automatic vectorization,
@@ -86,13 +88,13 @@ for more information on building the C++ and Python APIs from source.
 
 ## Contributing 
 
-Check out the [contribution guidelines](CONTRIBUTING.md) for more information
+Check out the [contribution guidelines](https://github.com/ml-explore/mlx/tree/main/CONTRIBUTING.md) for more information
 on contributing to MLX. See the
 [docs](https://ml-explore.github.io/mlx/build/html/install.html) for more
 information on building from source, and running tests.
 
 We are grateful for all of [our
-contributors](ACKNOWLEDGMENTS.md#Individual-Contributors). If you contribute
+contributors](https://github.com/ml-explore/mlx/tree/main/ACKNOWLEDGMENTS.md#Individual-Contributors). If you contribute
 to MLX and wish to be acknowledged, please add your name to the list in your
 pull request.
 

benchmarks/cpp/single_ops.cpp

@@ -73,6 +73,7 @@ void time_unary_ops() {
 
 void time_binary_ops() {
   int M = 1000, N = 100, K = 10;
+  auto condition = random::randint(0, 2, {M, N, K});
   auto a = random::uniform({M, N, K});
   auto b = random::uniform({M, N, K});
   auto device = default_device();
@@ -84,7 +85,9 @@ void time_binary_ops() {
   TIME(divide, a, b, device);
   TIME(maximum, a, b, device);
   TIME(minimum, a, b, device);
+  TIME(where, condition, a, b, device);
 
+  condition = array({true});
   b = random::uniform({1});
   eval(b);
   TIMEM("scalar", add, a, b, device);
@@ -93,7 +96,9 @@ void time_binary_ops() {
   TIMEM("scalar", multiply, a, b, device);
   TIMEM("vector-scalar", divide, a, b, device);
   TIMEM("scalar-vector", divide, b, a, device);
+  TIMEM("scalar-vector", where, condition, a, b, device);
 
+  condition = broadcast_to(array({true}), {1000, 100});
   a = broadcast_to(random::uniform({1}), {1000, 100});
   b = broadcast_to(random::uniform({1}), {1000, 100});
   eval(a, b);
@@ -101,6 +106,7 @@ void time_binary_ops() {
   TIMEM("scalar-scalar broadcast", subtract, a, b, device);
   TIMEM("scalar-scalar broadcast", multiply, a, b, device);
   TIMEM("scalar-scalar broadcast", divide, a, b, device);
+  TIMEM("scalar-scalar broadcast", where, condition, a, b, device);
 }
 
 void time_strided_ops() {

benchmarks/cpp/time_utils.h

@@ -17,14 +17,13 @@
             << std::setprecision(5) << time_fn(FUNC, ##__VA_ARGS__) << " msec" \
             << std::endl;
 
-#define TIMEM(MSG, FUNC, ...)                                                  \
-  std::cout << "Timing "                                                       \
-            << "(" << MSG << ") " << #FUNC << " ... " << std::flush            \
-            << std::setprecision(5) << time_fn(FUNC, ##__VA_ARGS__) << " msec" \
-            << std::endl;
+#define TIMEM(MSG, FUNC, ...)                                      \
+  std::cout << "Timing " << "(" << MSG << ") " << #FUNC << " ... " \
+            << std::flush << std::setprecision(5)                  \
+            << time_fn(FUNC, ##__VA_ARGS__) << " msec" << std::endl;
 
 template <typename F, typename... Args>
-double time_fn(F fn, Args... args) {
+double time_fn(F fn, Args&&... args) {
   // warmup
   for (int i = 0; i < 5; ++i) {
     eval(fn(std::forward<Args>(args)...));

benchmarks/python/comparative/bench_mlx.py

@@ -380,10 +380,6 @@ if __name__ == "__main__":
     if len(args.axis) > 1:
         args.axis.pop(0)
 
-    if args.print_pid:
-        print(os.getpid())
-        input("Press enter to run")
-
     if args.cpu:
         mx.set_default_device(mx.cpu)
     else:
@@ -406,6 +402,10 @@ if __name__ == "__main__":
     x = xs[0]
     axis = args.axis[0]
 
+    if args.print_pid:
+        print(os.getpid())
+        input("Press enter to run")
+
     if args.benchmark == "matmul_square":
         print(bench(matmul_square, x))
 

benchmarks/python/comparative/bench_torch.py

@@ -185,7 +185,7 @@ def prelu(x: torch.Tensor) -> torch.Tensor:
 def mish(x: torch.Tensor) -> torch.Tensor:
     y = x
     for _ in range(100):
-        return torch.nn.functional.mish(y)
+        y = torch.nn.functional.mish(y)
     sync_if_needed(x)
 
 
@@ -283,6 +283,14 @@ def topk(axis, x):
     sync_if_needed(x)
 
 
+@torch.no_grad()
+def step_function(x):
+    y = x
+    for i in range(100):
+        y = torch.where(y < 0, 0, 1)
+    sync_if_needed(x)
+
+
 @torch.no_grad()
 def selu(x):
     y = x
@@ -331,10 +339,6 @@ if __name__ == "__main__":
     if len(args.axis) > 1:
         args.axis.pop(0)
 
-    if args.print_pid:
-        print(os.getpid())
-        input("Press enter to run")
-
     torch.set_num_threads(1)
     device = "cpu" if args.cpu else "mps"
 
@@ -354,6 +358,10 @@ if __name__ == "__main__":
     x = xs[0]
     axis = args.axis[0]
 
+    if args.print_pid:
+        print(os.getpid())
+        input("Press enter to run")
+
     if args.benchmark == "matmul_square":
         print(bench(matmul_square, x))
 
@@ -446,5 +454,11 @@ if __name__ == "__main__":
     elif args.benchmark == "topk":
         print(bench(topk, axis, x))
 
+    elif args.benchmark == "step":
+        print(bench(step_function, x))
+
+    elif args.benchmark == "selu":
+        print(bench(selu, x))
+
     else:
-        raise ValueError("Unknown benchmark")
+        raise ValueError(f"Unknown benchmark `{args.benchmark}`.")

benchmarks/python/comparative/compare.py

@@ -16,7 +16,9 @@ def run_or_raise(*args, **kwargs):
         result = run(*args, capture_output=True, **kwargs)
         return float(result.stdout)
     except ValueError:
-        raise ValueError(f"stdout: {result.stdout}\nstderr: {result.stderr}")
+        raise ValueError(
+            f"stdout: {result.stdout.decode()}\nstderr: {result.stderr.decode()}"
+        )
 
 
 def compare(args):
@@ -80,10 +82,8 @@ if __name__ == "__main__":
     _filter = make_predicate(args.filter, args.negative_filter)
 
     if args.mlx_dtypes:
-        compare_filtered = (
-            lambda x: compare_mlx_dtypes(
-                x.split() + rest, args.mlx_dtypes[0], args.mlx_dtypes[1]
-            )
+        compare_filtered = lambda x: (
+            compare_mlx_dtypes(x.split() + rest, args.mlx_dtypes[0], args.mlx_dtypes[1])
             if _filter(x)
             else None
         )

benchmarks/python/compile_bench.py

@@ -0,0 +1,107 @@
+# Copyright © 2023-2024 Apple Inc.
+
+import argparse
+import math
+import random
+
+import mlx.core as mx
+from time_utils import time_fn
+
+
+def bench_gelu():
+    def gelu(x):
+        return x * (1 + mx.erf(x / math.sqrt(2))) / 2
+
+    x = mx.random.uniform(shape=(1000, 1024))
+
+    def gen_fun(fun):
+        def bench_fun(x):
+            for _ in range(10):
+                x = fun(x)
+            return x
+
+        return bench_fun
+
+    time_fn(gen_fun(gelu), x, msg="fixed gelu")
+    time_fn(gen_fun(mx.compile(gelu)), x, msg="compiled fixed gelu")
+
+    def randint():
+        return random.randint(1, x.shape[0])
+
+    def gen_fun(fun):
+        def bench_fun(x, y):
+            x = x[: randint()]
+            for _ in range(10):
+                x = fun(x)
+                y = fun(y)
+            return x, y
+
+        return bench_fun
+
+    y = mx.random.uniform(shape=(1000, 1024))
+    time_fn(gen_fun(gelu), x, y, msg="variable gelu")
+    time_fn(gen_fun(mx.compile(gelu)), x, y, msg="compiled variable gelu")
+    time_fn(
+        gen_fun(mx.compile(gelu, shapeless=True)),
+        x,
+        y,
+        msg="shapeless variable gelu",
+    )
+
+
+def bench_layernorm():
+    weight = mx.random.uniform(shape=(4096,)).astype(mx.float16)
+    bias = mx.random.uniform(shape=(4096,)).astype(mx.float16)
+    mx.eval(weight, bias)
+
+    def layernorm(x):
+        x = x.astype(mx.float32)
+        means = mx.mean(x, axis=-1, keepdims=True)
+        var = mx.var(x, axis=-1, keepdims=True)
+        x = (x - means) * mx.rsqrt(var + 1e-4)
+        x = x.astype(mx.float16)
+        return weight * x + bias
+
+    x = mx.random.uniform(shape=(1000, 4096)).astype(mx.float16)
+
+    def gen_fun(fun):
+        def bench_fun(x):
+            for _ in range(10):
+                x = fun(x)
+            return x
+
+        return bench_fun
+
+    time_fn(gen_fun(layernorm), x, msg="fixed layernorm")
+    time_fn(gen_fun(mx.compile(layernorm)), x, msg="compiled fixed layernorm")
+
+    def randint():
+        return random.randint(1, x.shape[0])
+
+    def gen_fun(fun):
+        def bench_fun(x):
+            x = x[: randint()]
+            for _ in range(10):
+                x = fun(x)
+            return x
+
+        return bench_fun
+
+    random.seed(0)
+    time_fn(gen_fun(layernorm), x, msg="variable layernorm")
+    random.seed(0)
+    time_fn(gen_fun(mx.compile(layernorm)), x, msg="compiled variable layernorm")
+    random.seed(0)
+    time_fn(
+        gen_fun(mx.compile(layernorm, shapeless=True)),
+        x,
+        msg="shapeless variable layernorm",
+    )
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser("Compile benchmarks.")
+    args = parser.parse_args()
+
+    bench_gelu()
+    bench_layernorm()

benchmarks/python/conv1d_bench.py

@@ -0,0 +1,123 @@
+import argparse
+import math
+import os
+import subprocess
+import time
+
+import mlx.core as mx
+import numpy as np
+import torch
+
+device_name = subprocess.check_output(["sysctl", "-n", "machdep.cpu.brand_string"])
+device_name = device_name.decode("utf-8").strip("\n")
+
+N_warmup = 10
+N_iter_bench = 100
+N_iter_func = 5
+
+
+def bench(f, a, b):
+    for i in range(N_warmup):
+        f(a, b)
+    torch.mps.synchronize()
+
+    s = time.perf_counter_ns()
+    for i in range(N_iter_bench):
+        f(a, b)
+    e = time.perf_counter_ns()
+    return (e - s) * 1e-9
+
+
+def make_mx_conv_1D(strides=1, padding=0, groups=1):
+    def mx_conv_1D(a, b):
+        ys = []
+        for _ in range(N_iter_func):
+            y = mx.conv1d(a, b, stride=strides, padding=padding, groups=groups)
+            ys.append(y)
+        mx.eval(ys)
+        return ys
+
+    return mx_conv_1D
+
+
+def make_pt_conv_1D(strides=1, padding=0, groups=1):
+    @torch.no_grad()
+    def pt_conv_1D(a, b):
+        ys = []
+        for _ in range(N_iter_func):
+            y = torch.conv1d(a, b, stride=strides, padding=padding, groups=groups)
+            ys.append(y)
+        torch.mps.synchronize()
+        return ys
+
+    return pt_conv_1D
+
+
+def bench_shape(N, iH, C, wH, O, strides, padding, np_dtype, groups):
+    scale = 1.0 / math.sqrt(wH * C)
+    a_np = np.random.uniform(0, 0.5, (N, iH, C)).astype(np_dtype)
+    b_np = np.random.uniform(-scale, scale, (O, wH, int(C / groups))).astype(np_dtype)
+
+    a_mx = mx.array(a_np)
+    b_mx = mx.array(b_np)
+
+    a_pt = torch.from_numpy(a_np.transpose((0, 2, 1))).to("mps")
+    b_pt = torch.from_numpy(b_np.transpose((0, 2, 1))).to("mps")
+
+    torch.mps.synchronize()
+
+    f_mx = make_mx_conv_1D(strides, padding, groups)
+    f_pt = make_pt_conv_1D(strides, padding, groups)
+
+    time_torch = bench(f_pt, a_pt, b_pt)
+    time_mlx = bench(f_mx, a_mx, b_mx)
+
+    out_mx = mx.conv1d(a_mx, b_mx, stride=strides, padding=padding, groups=groups)
+    out_pt = torch.conv1d(
+        a_pt.to("cpu"), b_pt.to("cpu"), stride=strides, padding=padding, groups=groups
+    )
+    out_pt = torch.permute(out_pt, (0, 2, 1))
+    out_pt = out_pt.numpy(force=True)
+
+    atol = 2e-5 if np_dtype == np.float32 else 1e-4
+
+    if not np.allclose(out_pt, out_mx, atol=atol):
+        print(
+            f"Failed at {(N, iH, C)}, {(O, wH, C)} [strides = {strides}, padding = {padding}, groups = {groups}] with max(|a - b|) = {np.max(np.abs(out_pt - out_mx))}"
+        )
+
+    return time_mlx, time_torch
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Run conv benchmarks")
+
+    dtypes = ("float32",)
+    shapes = (
+        (4, 32, 32, 5, 32, 1, 2, 1),
+        (4, 32, 32, 5, 32, 1, 2, 2),
+        (4, 32, 32, 5, 32, 1, 2, 4),
+        (4, 32, 32, 5, 32, 1, 2, 8),
+        (4, 32, 32, 5, 32, 1, 2, 8),
+        (4, 32, 32, 5, 32, 1, 2, 16),
+        (4, 32, 32, 5, 32, 1, 2, 32),
+        (4, 32, 256, 5, 512, 1, 2, 2),
+        (4, 32, 256, 5, 512, 1, 2, 128),
+        (4, 32, 256, 5, 512, 1, 2, 256),
+    )
+
+    for dtype in dtypes:
+        print("(N,  iH,  C),  (O,  wH,  C),   dtype,  stride, pads, groups, diff%")
+        for N, iH, C, wH, O, strides, padding, groups in shapes:
+            np_dtype = getattr(np, dtype)
+            time_mlx, time_torch = bench_shape(
+                N, iH, C, wH, O, strides, padding, np_dtype, groups
+            )
+            diff = time_torch / time_mlx - 1.0
+
+            print(
+                f"({N}, {iH:3d}, {C:3d}), ({O:3d}, {wH:2d}, {C:3d}), {dtype}, {strides:5d}, {padding:4d}, {groups:6d}, {100. * diff:+5.2f}%"
+            )
+
+            if time_mlx >= 2.0 * time_torch:
+                print("ATTENTION ^^^^^^^")

benchmarks/python/conv_bench.py

@@ -0,0 +1,135 @@
+import argparse
+import math
+import os
+import subprocess
+import time
+
+import mlx.core as mx
+import numpy as np
+import torch
+
+device_name = subprocess.check_output(["sysctl", "-n", "machdep.cpu.brand_string"])
+device_name = device_name.decode("utf-8").strip("\n")
+
+N_warmup = 10
+N_iter_bench = 100
+N_iter_func = 5
+
+
+def bench(f, a, b):
+    for i in range(N_warmup):
+        f(a, b)
+    torch.mps.synchronize()
+
+    s = time.perf_counter_ns()
+    for i in range(N_iter_bench):
+        f(a, b)
+    e = time.perf_counter_ns()
+    return (e - s) * 1e-9
+
+
+def make_mx_conv_2D(strides=(1, 1), padding=(0, 0), groups=1):
+    def mx_conv_2D(a, b):
+        ys = []
+        for i in range(N_iter_func):
+            y = mx.conv2d(a, b, stride=strides, padding=padding, groups=groups)
+            ys.append(y)
+        mx.eval(ys)
+        return ys
+
+    return mx_conv_2D
+
+
+def make_pt_conv_2D(strides=(1, 1), padding=(0, 0), groups=1):
+    @torch.no_grad()
+    def pt_conv_2D(a, b):
+        ys = []
+        for i in range(N_iter_func):
+            y = torch.conv2d(a, b, stride=strides, padding=padding, groups=groups)
+            ys.append(y)
+        torch.mps.synchronize()
+        return ys
+
+    return pt_conv_2D
+
+
+def bench_shape(N, H, W, C, kH, kW, O, strides, padding, groups, np_dtype):
+    scale = 1.0 / math.sqrt(kH * kH * C)
+    a_np = np.random.uniform(0, 0.5, (N, H, W, C)).astype(np_dtype)
+    b_np = np.random.uniform(-scale, scale, (O, kH, kW, int(C / groups))).astype(
+        np_dtype
+    )
+
+    a_mx = mx.array(a_np)
+    b_mx = mx.array(b_np)
+
+    a_pt = torch.from_numpy(a_np.transpose((0, 3, 1, 2))).to("mps")
+    b_pt = torch.from_numpy(b_np.transpose((0, 3, 1, 2))).to("mps")
+
+    torch.mps.synchronize()
+
+    f_mx = make_mx_conv_2D(strides, padding, groups)
+    f_pt = make_pt_conv_2D(strides, padding, groups)
+
+    time_torch = bench(f_pt, a_pt, b_pt)
+    time_mlx = bench(f_mx, a_mx, b_mx)
+
+    out_mx = mx.conv2d(a_mx, b_mx, stride=strides, padding=padding, groups=groups)
+    out_pt = torch.conv2d(
+        a_pt.to("cpu"), b_pt.to("cpu"), stride=strides, padding=padding, groups=groups
+    )
+    out_pt = torch.permute(out_pt, (0, 2, 3, 1))
+    out_pt = out_pt.numpy(force=True)
+
+    atol = 2e-5 if np_dtype == np.float32 else 1e-4
+
+    if not np.allclose(out_pt, out_mx, atol=atol):
+        print(
+            f"Failed at {(N, H, W, C)}, {(O, kH, kW, C)} [strides = {strides}, padding = {padding}, groups = {groups}] with max(|a - b|) = {np.max(np.abs(out_pt - out_mx))}"
+        )
+
+    return time_mlx, time_torch
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Run conv benchmarks")
+
+    dtypes = ("float32",)
+    shapes = (
+        (4, 32, 32, 32, 5, 5, 32, (1, 1), (2, 2), 1),
+        (4, 32, 32, 64, 5, 5, 64, (1, 1), (2, 2), 1),
+        (4, 32, 32, 128, 5, 5, 128, (1, 1), (2, 2), 1),
+        (4, 32, 32, 256, 5, 5, 256, (1, 1), (2, 2), 1),
+        (4, 32, 32, 512, 5, 5, 512, (1, 1), (2, 2), 1),
+        (4, 64, 64, 32, 5, 5, 32, (1, 1), (2, 2), 1),
+        (4, 64, 64, 64, 5, 5, 64, (1, 1), (2, 2), 1),
+        (4, 64, 64, 128, 5, 5, 128, (1, 1), (2, 2), 1),
+        (4, 64, 64, 256, 5, 5, 256, (1, 1), (2, 2), 1),
+        (4, 64, 64, 256, 5, 5, 256, (1, 1), (2, 2), 2),
+        (4, 64, 64, 256, 5, 5, 256, (1, 1), (2, 2), 16),
+        (4, 64, 64, 256, 5, 5, 256, (1, 1), (2, 2), 64),
+        (4, 128, 128, 32, 5, 5, 32, (1, 1), (2, 2), 1),
+        (4, 128, 128, 64, 5, 5, 64, (1, 1), (2, 2), 1),
+        (4, 128, 128, 128, 5, 5, 128, (1, 1), (2, 2), 1),
+        (4, 256, 256, 32, 5, 5, 3, (1, 1), (2, 2), 1),
+        (4, 256, 256, 3, 5, 5, 32, (1, 1), (2, 2), 1),
+        (4, 128, 128, 64, 5, 5, 3, (1, 1), (2, 2), 1),
+        (4, 128, 128, 3, 5, 5, 64, (1, 1), (2, 2), 1),
+    )
+
+    for dtype in dtypes:
+        print(
+            "(N,   H,   W,   C), (  O, kH, kW,   C),   dtype, stride,   pads,  groups, diff%"
+        )
+        for N, H, W, C, kH, kW, O, strides, padding, groups in shapes:
+            np_dtype = getattr(np, dtype)
+            time_mlx, time_torch = bench_shape(
+                N, H, W, C, kH, kW, O, strides, padding, groups, np_dtype
+            )
+            diff = time_torch / time_mlx - 1.0
+
+            print(
+                f"({N}, {H:3d}, {W:3d}, {C:3d}), ({O:3d}, {kH:2d}, {kW:2d}, {C:3d}), {dtype}, {strides}, {padding}, {groups:7d}, {100. * diff:+5.2f}%"
+            )
+            if time_mlx >= 2.0 * time_torch:
+                print("ATTENTION ^^^^^^^")

benchmarks/python/einsum_bench.py

@@ -0,0 +1,84 @@
+# Copyright © 2024 Apple Inc.
+
+import time
+
+import mlx.core as mx
+import numpy as np
+
+
+def timeit(fn, its=100, args=[]):
+    for _ in range(5):
+        fn(*args)
+    tic = time.perf_counter()
+    for _ in range(its):
+        fn(*args)
+    toc = time.perf_counter()
+    return 1e3 * (toc - tic) / its
+
+
+def time_little_einsum_path():
+    subscripts = "ik,kj->ij"
+    x = mx.ones((32, 32))
+    y = mx.ones((32, 32))
+    mx_time = timeit(mx.einsum_path, args=(subscripts, x, y))
+
+    x = np.array(x)
+    y = np.array(y)
+    np_time = timeit(np.einsum_path, args=(subscripts, x, y))
+    print("Timing little einsum path...")
+    print(f"MLX ... {mx_time:.3f} ms")
+    print(f"NumPy... {np_time:.3f} ms")
+
+
+def time_big_einsum_path():
+    chars = list("abcdefgh")
+    char_to_dim = {c: v for v, c in enumerate(chars)}
+
+    num_inputs = 10
+    inputs = []
+    subscripts = []
+    for _ in range(num_inputs):
+        subscript = np.random.choice(chars, size=5, replace=False).tolist()
+        subscripts.append("".join(subscript))
+        inputs.append(np.ones(list(char_to_dim[c] for c in subscript)))
+    subscripts = ",".join(subscripts)
+
+    np_time = timeit(np.einsum_path, args=(subscripts, *inputs))
+
+    inputs = [mx.array(x) for x in inputs]
+    mx_time = timeit(mx.einsum_path, args=(subscripts, *inputs))
+    print("Timing big einsum path...")
+    print(f"MLX ... {mx_time:.3f} ms")
+    print(f"NumPy... {np_time:.3f} ms")
+
+
+def time_attention():
+    def regular_attention(x):
+        # shape [batch, sequence, num_heads, head_dim]
+        queries, keys, values = x, x, x
+        scores = queries.transpose(0, 2, 1, 3) @ keys.transpose(0, 2, 3, 1)
+        scores = mx.softmax(scores, axis=-1)
+        output = (scores @ values.transpose(0, 2, 1, 3)).swapaxes(1, 2)
+        mx.eval(output)
+
+    def einsum_attention(x):
+        # shape [batch, sequence, num_heads, head_dim]
+        queries, keys, values = x, x, x
+        scores = mx.einsum("itjk,iujk->ijtu", queries, keys)
+        scores = mx.softmax(scores, axis=-1)
+        output = mx.einsum("ijtu,iujk->itjk", scores, values)
+        mx.eval(output)
+
+    x = mx.random.uniform(shape=(8, 512, 32, 128))
+
+    regular_time = timeit(regular_attention, args=(x,))
+    ein_time = timeit(einsum_attention, args=(x,))
+    print("Timing einsum attention...")
+    print(f"Regular ... {regular_time:.3f} ms")
+    print(f"Einsum ... {ein_time:.3f} ms")
+
+
+if __name__ == "__main__":
+    time_little_einsum_path()
+    time_big_einsum_path()
+    time_attention()

benchmarks/python/fft_bench.py

@@ -0,0 +1,118 @@
+# Copyright © 2024 Apple Inc.
+
+import matplotlib
+import mlx.core as mx
+import numpy as np
+import sympy
+import torch
+from time_utils import measure_runtime
+
+matplotlib.use("Agg")
+import matplotlib.pyplot as plt
+
+
+def bandwidth_gb(runtime_ms, system_size):
+    bytes_per_fft = np.dtype(np.complex64).itemsize * 2
+    bytes_per_gb = 1e9
+    ms_per_s = 1e3
+    return system_size * bytes_per_fft / runtime_ms * ms_per_s / bytes_per_gb
+
+
+def run_bench(system_size, fft_sizes, backend="mlx", dim=1):
+    def fft_mlx(x):
+        if dim == 1:
+            out = mx.fft.fft(x)
+        elif dim == 2:
+            out = mx.fft.fft2(x)
+        mx.eval(out)
+        return out
+
+    def fft_mps(x):
+        if dim == 1:
+            out = torch.fft.fft(x)
+        elif dim == 2:
+            out = torch.fft.fft2(x)
+        torch.mps.synchronize()
+        return out
+
+    bandwidths = []
+    for n in fft_sizes:
+        batch_size = system_size // n**dim
+        shape = [batch_size] + [n for _ in range(dim)]
+        if backend == "mlx":
+            x_np = np.random.uniform(size=(system_size // n, n)).astype(np.complex64)
+            x = mx.array(x_np)
+            mx.eval(x)
+            fft = fft_mlx
+        elif backend == "mps":
+            x_np = np.random.uniform(size=(system_size // n, n)).astype(np.complex64)
+            x = torch.tensor(x_np, device="mps")
+            torch.mps.synchronize()
+            fft = fft_mps
+        else:
+            raise NotImplementedError()
+        runtime_ms = measure_runtime(fft, x=x)
+        bandwidth = bandwidth_gb(runtime_ms, np.prod(shape))
+        print(n, bandwidth)
+        bandwidths.append(bandwidth)
+
+    return np.array(bandwidths)
+
+
+def time_fft():
+    x = np.array(range(2, 512))
+    system_size = int(2**26)
+
+    print("MLX GPU")
+    with mx.stream(mx.gpu):
+        gpu_bandwidths = run_bench(system_size=system_size, fft_sizes=x)
+
+    print("MPS GPU")
+    mps_bandwidths = run_bench(system_size=system_size, fft_sizes=x, backend="mps")
+
+    print("CPU")
+    system_size = int(2**20)
+    with mx.stream(mx.cpu):
+        cpu_bandwidths = run_bench(system_size=system_size, fft_sizes=x)
+
+    x = np.array(x)
+
+    all_indices = x - x[0]
+    radix_2to13 = (
+        np.array([i for i in x if all(p <= 13 for p in sympy.primefactors(i))]) - x[0]
+    )
+    bluesteins = (
+        np.array([i for i in x if any(p > 13 for p in sympy.primefactors(i))]) - x[0]
+    )
+
+    for indices, name in [
+        (all_indices, "All"),
+        (radix_2to13, "Radix 2-13"),
+        (bluesteins, "Bluestein's"),
+    ]:
+        # plot bandwidths
+        print(name)
+        plt.scatter(x[indices], gpu_bandwidths[indices], color="green", label="GPU")
+        plt.scatter(x[indices], mps_bandwidths[indices], color="blue", label="MPS")
+        plt.scatter(x[indices], cpu_bandwidths[indices], color="red", label="CPU")
+        plt.title(f"MLX FFT Benchmark -- {name}")
+        plt.xlabel("N")
+        plt.ylabel("Bandwidth (GB/s)")
+        plt.legend()
+        plt.savefig(f"{name}.png")
+        plt.clf()
+
+    av_gpu_bandwidth = np.mean(gpu_bandwidths)
+    av_mps_bandwidth = np.mean(mps_bandwidths)
+    av_cpu_bandwidth = np.mean(cpu_bandwidths)
+    print("Average bandwidths:")
+    print("GPU:", av_gpu_bandwidth)
+    print("MPS:", av_mps_bandwidth)
+    print("CPU:", av_cpu_bandwidth)
+
+    portion_faster = len(np.where(gpu_bandwidths > mps_bandwidths)[0]) / len(x)
+    print("Percent MLX faster than MPS: ", portion_faster * 100)
+
+
+if __name__ == "__main__":
+    time_fft()

benchmarks/python/gather_bench.py

@@ -0,0 +1,53 @@
+# Copyright © 2023-2024 Apple Inc.
+
+import argparse
+from time import time
+
+import mlx.core as mx
+import torch
+from time_utils import measure_runtime
+
+
+def benchmark_gather_mlx(x_shape, idx_shape):
+    def gather(x, idx):
+        mx.eval(x[idx])
+
+    idx = mx.random.randint(0, x_shape[0] - 1, idx_shape)
+    x = mx.random.normal(x_shape).astype(mx.float32)
+
+    runtime = measure_runtime(gather, x=x, idx=idx)
+    print(f"MLX: {runtime:.3f}ms")
+
+
+def benchmark_gather_torch(x_shape, idx_shape, device):
+    def gather(x, idx, device):
+        _ = x[idx]
+        if device == torch.device("mps"):
+            torch.mps.synchronize()
+
+    idx = torch.randint(0, x_shape[0] - 1, idx_shape).to(device)
+    x = torch.randn(x_shape, dtype=torch.float32).to(device)
+
+    runtime = measure_runtime(gather, x=x, idx=idx, device=device)
+    print(f"PyTorch: {runtime:.3f}ms")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser("Gather benchmarks.")
+    parser.add_argument("--cpu", action="store_true", help="Use the CPU.")
+    args = parser.parse_args()
+
+    if args.cpu:
+        mx.set_default_device(mx.cpu)
+        device = torch.device("cpu")
+    else:
+        device = torch.device("mps")
+
+    idx_shapes = [(1_000_000,), (100_000,), ()]
+    x_shapes = [(100, 64), (100, 1024), (4, 1_000_000)]
+
+    for x_shape, idx_shape in zip(x_shapes, idx_shapes):
+        print("=" * 20)
+        print(f"X {x_shape}, Indices {idx_shape}")
+        benchmark_gather_mlx(x_shape, idx_shape)
+        benchmark_gather_torch(x_shape, idx_shape, device=device)

benchmarks/python/hadamard_bench.py

@@ -0,0 +1,70 @@
+import argparse
+
+import matplotlib
+import mlx.core as mx
+import numpy as np
+from time_utils import measure_runtime
+
+matplotlib.use("Agg")
+import matplotlib.pyplot as plt
+
+
+def had(x):
+    y = mx.hadamard_transform(x)
+    mx.eval(y)
+
+
+def copy(x):
+    y = x + 1.0
+    mx.eval(y)
+
+
+def run(dtype):
+    system_size = 2**26
+    outputs = {}
+    for test_fn in (had, copy):
+        for m in [1, 12, 20, 28]:
+            if test_fn == copy:
+                key = "copy"
+            elif m == 1:
+                key = "had_2^k"
+            else:
+                key = "had_m*2^k"
+            outputs.setdefault(key, {})
+            for k in range(7, 14):
+                n = m * 2**k
+                if n > 2**15:
+                    continue
+                x_np = np.random.normal(size=(system_size // n, n)).astype(dtype)
+                x = mx.array(x_np)
+                runtime_ms = measure_runtime(test_fn, x=x)
+                bytes_per_gb = 1e9
+                ms_per_s = 1e3
+                bytes_per_had = np.dtype(x_np.dtype).itemsize * 2
+                bandwidth_gb = (
+                    system_size * bytes_per_had / runtime_ms * ms_per_s / bytes_per_gb
+                )
+                print(n, bandwidth_gb)
+                outputs[key][n] = bandwidth_gb
+
+    colors = {
+        "copy": "black",
+        "had_2^k": "steelblue",
+        "had_m*2^k": "skyblue",
+    }
+    for key, output in outputs.items():
+        plt.scatter(output.keys(), output.values(), color=colors[key], label=key)
+    plt.title(f"MLX Hadamard Benchmark -- {dtype.__name__}")
+    plt.xlabel("N")
+    plt.ylabel("Bandwidth (GB/s)")
+    plt.legend()
+    plt.savefig(f"bench_{dtype.__name__}.png")
+    plt.clf()
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--fp16", action="store_true")
+    args = parser.parse_args()
+    dtype = np.float16 if args.fp16 else np.float32
+    run(dtype)

benchmarks/python/layer_norm_bench.py

@@ -0,0 +1,41 @@
+# Copyright © 2023-2024 Apple Inc.
+
+import mlx.core as mx
+import mlx.nn as nn
+from time_utils import time_fn
+
+
+def layer_norm(x, w, b, eps):
+    ot = x.dtype
+    x = x.astype(mx.float32)
+    mu = mx.mean(x, -1, keepdims=True)
+    v = mx.var(x, -1, keepdims=True)
+    return (x - mu) * mx.rsqrt(v + eps) * w + b
+
+
+def time_layer_norm():
+    f1 = lambda x, w, b, y: (layer_norm(x, w, b, 1e-5) * y).sum()
+    f2 = lambda x, w, b, y: (mx.fast.layer_norm(x, w, b, 1e-5) * y).sum()
+    g1 = mx.grad(f1, argnums=(0, 1, 2))
+    g2 = mx.grad(f2, argnums=(0, 1, 2))
+
+    x = mx.random.uniform(shape=(8, 1024, 4096)).astype(mx.float16)
+    w = mx.random.uniform(shape=(4096,)).astype(mx.float16)
+    b = mx.random.uniform(shape=(4096,)).astype(mx.float16)
+    y = mx.random.uniform(shape=(8, 1024, 4096)).astype(mx.float16)
+    mx.eval(x, w, b, y)
+
+    def layer_norm_loop(g, x, w, b):
+        gx, gw, gb = x, w, b
+        for _ in range(32):
+            gx, gw, gb = g(gx, gw, gb, y)
+        return gx, gw, gb
+
+    time_fn(layer_norm_loop, g1, x, w, b)
+    time_fn(layer_norm_loop, g2, x, w, b)
+    time_fn(layer_norm_loop, mx.compile(g1), x, w, b)
+    time_fn(layer_norm_loop, mx.compile(g2), x, w, b)
+
+
+if __name__ == "__main__":
+    time_layer_norm()

benchmarks/python/rms_norm_bench.py

@@ -0,0 +1,39 @@
+# Copyright © 2023-2024 Apple Inc.
+
+import mlx.core as mx
+import mlx.nn as nn
+from time_utils import time_fn
+
+
+def rms_norm(x, w, eps):
+    ot = x.dtype
+    x = x.astype(mx.float32)
+    n = mx.rsqrt(x.square().mean(-1, keepdims=True) + eps)
+    return (x * n).astype(ot) * w
+
+
+def time_rms_norm():
+    f1 = lambda x, w, y: (rms_norm(x, w, 1e-5) * y).sum()
+    f2 = lambda x, w, y: (mx.fast.rms_norm(x, w, 1e-5) * y).sum()
+    g1 = mx.grad(f1, argnums=(0, 1))
+    g2 = mx.grad(f2, argnums=(0, 1))
+
+    x = mx.random.uniform(shape=(8, 1024, 4096)).astype(mx.float16)
+    w = mx.random.uniform(shape=(4096,)).astype(mx.float16)
+    y = mx.random.uniform(shape=(8, 1024, 4096)).astype(mx.float16)
+    mx.eval(x, w, y)
+
+    def rms_norm_loop(g, x, w):
+        gx, gw = x, w
+        for _ in range(32):
+            gx, gw = g(gx, gw, y)
+        return gx, gw
+
+    time_fn(rms_norm_loop, g1, x, w)
+    time_fn(rms_norm_loop, g2, x, w)
+    time_fn(rms_norm_loop, mx.compile(g1), x, w)
+    time_fn(rms_norm_loop, mx.compile(g2), x, w)
+
+
+if __name__ == "__main__":
+    time_rms_norm()

benchmarks/python/rope_bench.py

@@ -0,0 +1,35 @@
+# Copyright © 2023-2024 Apple Inc.
+
+import mlx.core as mx
+import mlx.nn as nn
+from time_utils import time_fn
+
+
+def time_rope():
+    rope = nn.RoPE(64)
+
+    # vec
+    x = mx.random.uniform(shape=(1, 32, 1, 128)).astype(mx.float16)
+    mx.eval(x)
+
+    def rope_vec(x):
+        for _ in range(32):
+            x = rope(x, offset=100)
+        return x
+
+    time_fn(rope_vec, x)
+
+    # matrix
+    x = mx.random.uniform(shape=(1, 32, 1024, 128)).astype(mx.float16)
+    mx.eval(x)
+
+    def rope_mat(x):
+        for _ in range(32):
+            x = rope(x)
+        return x
+
+    time_fn(rope_mat, x)
+
+
+if __name__ == "__main__":
+    time_rope()

benchmarks/python/scatter_bench.py

@@ -0,0 +1,96 @@
+# Copyright © 2023-2024 Apple Inc.
+
+import argparse
+
+import mlx.core as mx
+import torch
+from time_utils import measure_runtime
+
+
+def benchmark_scatter_mlx(dst_shape, x_shape, idx_shapes):
+    def scatter(dst, x, idx):
+        dst[*idx] = x
+        mx.eval(dst)
+
+    idx = []
+    for idx_shape in idx_shapes:
+        idx.append(mx.random.randint(0, dst_shape[0] - 1, idx_shape))
+    x = mx.random.normal(x_shape).astype(mx.float32)
+    dst = mx.random.normal(dst_shape).astype(mx.float32)
+
+    runtime = measure_runtime(scatter, dst=dst, x=x, idx=idx)
+    print(f"MLX: {runtime:.3f}ms")
+
+
+def benchmark_scatter_torch(dst_shape, x_shape, idx_shapes, device):
+    def gather(dst, x, idx, device):
+        dst[*idx] = x
+        if device == torch.device("mps"):
+            torch.mps.synchronize()
+
+    idx = []
+    for idx_shape in idx_shapes:
+        idx.append(torch.randint(0, dst_shape[0] - 1, idx_shape).to(device))
+    x = torch.randn(x_shape, dtype=torch.float32).to(device)
+    dst = torch.randn(dst_shape, dtype=torch.float32).to(device)
+
+    runtime = measure_runtime(gather, dst=dst, x=x, idx=idx, device=device)
+    print(f"PyTorch: {runtime:.3f}ms")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser("Gather benchmarks.")
+    parser.add_argument("--cpu", action="store_true", help="Use the CPU.")
+    args = parser.parse_args()
+
+    if args.cpu:
+        mx.set_default_device(mx.cpu)
+        device = torch.device("cpu")
+    else:
+        device = torch.device("mps")
+
+    dst_shapes = [
+        (10, 64),
+        (100_000, 64),
+        (1_000_000, 64),
+        (100_000,),
+        (2_000_00,),
+        (20_000_000,),
+        (10000, 64),
+        (100, 64),
+        (100, 10_000, 64),
+        (10, 100, 100, 21),
+        (1_000, 1_000, 10),
+    ]
+    idx_shapes = [
+        [(1_000_000,)],
+        [(1_000_000,)],
+        [(100_000,)],
+        [(1_000_000,)],
+        [(20_000_000,)],
+        [(20_000_000,)],
+        [(1000000,)],
+        [(10000000,)],
+        [(1_000,)],
+        [(10_000,)],
+        [(1_000,), (1_000,)],
+    ]
+    x_shapes = [
+        (1_000_000, 64),
+        (1_000_000, 64),
+        (100_000, 64),
+        (1_000_000,),
+        (20_000_000,),
+        (20_000_000,),
+        (1000000, 64),
+        (10000000, 64),
+        (1_000, 10_000, 64),
+        (10_000, 100, 100, 21),
+        (1_000, 10),
+    ]
+
+    for dst_shape, x_shape, idx_shape in zip(dst_shapes, x_shapes, idx_shapes):
+        print("=" * 20)
+        print(f"X {x_shape}, Indices {idx_shape}")
+        benchmark_scatter_mlx(dst_shape, x_shape, idx_shape)
+        benchmark_scatter_torch(dst_shape, x_shape, idx_shape, device=device)

benchmarks/python/sdpa_bench.py

@@ -0,0 +1,62 @@
+import argparse
+import math
+
+import mlx.core as mx
+from time_utils import time_fn
+
+MAX_SEQ = 300
+START_SEQ = 100
+SEQ_INCREMENT = 50
+
+
+def time_self_attention_primitives():
+    mx.random.seed(3)
+    B = 2
+    H = 38
+    D = 64
+    for R in range(START_SEQ, MAX_SEQ, SEQ_INCREMENT):
+        q = mx.random.uniform(shape=(B, H, R, D))
+        k = mx.random.uniform(shape=(B, H, R, D))
+        v = mx.random.uniform(shape=(B, H, R, D))
+        scale = 1.0 / math.sqrt(float(D))
+        mx.eval(q, k, v)
+
+        def sdpa_primitives(qs, ks, vs, alpha):
+            s = (alpha * qs) @ ks.transpose(0, 1, 3, 2)
+            p = mx.softmax(s.astype(mx.float32), axis=-1).astype(s.dtype)
+            o = p @ vs
+            return o
+
+        time_fn(sdpa_primitives, q, k, v, scale)
+
+
+def time_self_attention_sdpa():
+    mx.random.seed(3)
+    B = 2
+    H = 38
+    D = 64
+    for R in range(START_SEQ, MAX_SEQ, SEQ_INCREMENT):
+        q = mx.random.uniform(shape=(B, H, R, D))
+        k = mx.random.uniform(shape=(B, H, R, D))
+        v = mx.random.uniform(shape=(B, H, R, D))
+        scale = 1.0 / math.sqrt(float(D))
+        mx.eval(q, k, v)
+
+        def sdpa_fused(qs, ks, vs, alpha):
+            o = mx.fast.scaled_dot_product_attention(qs, ks, vs, scale=alpha)
+            return o
+
+        time_fn(sdpa_fused, q, k, v, scale)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser("MLX benchmarks.")
+    parser.add_argument("--gpu", action="store_true", help="Use the Metal back-end.")
+    args = parser.parse_args()
+    if args.gpu:
+        mx.set_default_device(mx.gpu)
+    else:
+        mx.set_default_device(mx.cpu)
+
+    time_self_attention_sdpa()
+    time_self_attention_primitives()

benchmarks/python/time_utils.py

@@ -1,4 +1,4 @@
-# Copyright © 2023 Apple Inc.
+# Copyright © 2023-2024 Apple Inc.
 
 import time
 
@@ -6,7 +6,11 @@ import mlx.core as mx
 
 
 def time_fn(fn, *args, **kwargs):
-    print(f"Timing {fn.__name__} ...", end=" ")
+    msg = kwargs.pop("msg", None)
+    if msg:
+        print(f"Timing {msg} ...", end=" ")
+    else:
+        print(f"Timing {fn.__name__} ...", end=" ")
 
     # warmup
     for _ in range(5):
@@ -20,3 +24,15 @@ def time_fn(fn, *args, **kwargs):
 
     msec = 1e3 * (toc - tic) / num_iters
     print(f"{msec:.5f} msec")
+
+
+def measure_runtime(fn, **kwargs):
+    # Warmup
+    for _ in range(5):
+        fn(**kwargs)
+
+    tic = time.time()
+    iters = 100
+    for _ in range(iters):
+        fn(**kwargs)
+    return (time.time() - tic) * 1000 / iters

docs/.gitignore

@@ -1,2 +1,3 @@
 src/python/_autosummary*/
 src/python/nn/_autosummary*/
+src/python/optimizers/_autosummary*/

docs/Doxyfile

@@ -0,0 +1,50 @@
+################################################################################
+# Primary project setup.                                                       #
+################################################################################
+
+PROJECT_NAME           = "MLX"
+OUTPUT_DIRECTORY       = build
+XML_OUTPUT             = xml
+HTML_OUTPUT            = html
+STRIP_FROM_PATH        = ../
+INPUT                  = ../mlx
+FILE_PATTERNS          = *.h
+EXCLUDE_PATTERNS       = */private/*
+CREATE_SUBDIRS         = NO
+FULL_PATH_NAMES        = YES
+RECURSIVE              = YES
+GENERATE_HTML          = YES
+GENERATE_LATEX         = NO
+GENERATE_XML           = YES
+XML_PROGRAMLISTING     = YES
+
+################################################################################
+# Doxygen preprocessor / parser control.                                       #
+################################################################################
+
+ENABLE_PREPROCESSING   = YES
+MACRO_EXPANSION        = YES
+EXPAND_ONLY_PREDEF     = NO
+SKIP_FUNCTION_MACROS   = NO
+
+################################################################################
+# Compound extraction control.                                                 #
+################################################################################
+
+EXTRACT_ALL            = YES
+EXTRACT_PACKAGE        = YES
+EXTRACT_STATIC         = YES
+CASE_SENSE_NAMES       = NO
+
+################################################################################
+# Docstring control / customization.                                           #
+################################################################################
+
+JAVADOC_AUTOBRIEF      = YES
+
+################################################################################
+# Warning suppression.                                                         #
+################################################################################
+
+QUIET                  = YES
+WARN_IF_UNDOCUMENTED   = NO

docs/README.md

@@ -2,12 +2,16 @@
 
 ### Setup (do once)
 
-Install [sphinx](https://www.sphinx-doc.org/en/master/usage/installation.html)
-for example with `conda`:
+Install Doxygen:
 
 ```
-conda install sphinx
-pip install sphinx-book-theme
+brew install doxygen
+```
+
+Install Python packages:
+
+```
+pip install -r requirements.txt
 ```
 
 ### Build
@@ -15,7 +19,7 @@ pip install sphinx-book-theme
 Build the docs from `mlx/docs/`
 
 ```
-make html
+doxygen && make html
 ```
 
 View the docs by running a server in `mlx/docs/build/html/`:

docs/requirements.txt

@@ -0,0 +1,4 @@
+sphinx
+breathe
+sphinx-book-theme
+mlx

docs/src/_templates/nn-module-template.rst

@@ -4,16 +4,17 @@
 
 .. autoclass:: {{ objname }}
 
-   {#{% block methods %}
+   {% block methods %}
 
    {% if methods %}
    .. rubric:: {{ _('Methods') }}
 
    .. autosummary::
    {% for item in methods %}
-      {%- if item not in inherited_members and item != '__init__' %}
+      {%- if item not in inherited_members and item != "__init__" %}
          ~{{ name }}.{{ item }}
       {%- endif %}
    {%- endfor %}
    {% endif %}
-   {% endblock %}#}
+   {% endblock %}
+

docs/src/conf.py

@@ -22,22 +22,28 @@ extensions = [
     "sphinx.ext.autosummary",
     "sphinx.ext.intersphinx",
     "sphinx.ext.napoleon",
+    "breathe",
 ]
 
 python_use_unqualified_type_names = True
 autosummary_generate = True
+autosummary_filename_map = {"mlx.core.Stream": "stream_class"}
 
 intersphinx_mapping = {
-    "https://docs.python.org/3": None,
-    "https://numpy.org/doc/stable/": None,
+    "python": ("https://docs.python.org/3", None),
+    "numpy": ("https://numpy.org/doc/stable/", None),
 }
 
+breathe_projects = {"mlx": "../build/xml"}
+breathe_default_project = "mlx"
+
 templates_path = ["_templates"]
 html_static_path = ["_static"]
 source_suffix = ".rst"
-master_doc = "index"
+main_doc = "index"
 highlight_language = "python"
 pygments_style = "sphinx"
+add_module_names = False
 
 # -- Options for HTML output -------------------------------------------------
 
@@ -48,11 +54,44 @@ html_theme_options = {
     "repository_url": "https://github.com/ml-explore/mlx",
     "use_repository_button": True,
     "navigation_with_keys": False,
+    "logo": {
+        "image_light": "_static/mlx_logo.png",
+        "image_dark": "_static/mlx_logo_dark.png",
+    },
 }
 
-html_logo = "_static/mlx_logo.png"
-
 
 # -- Options for HTMLHelp output ---------------------------------------------
 
 htmlhelp_basename = "mlx_doc"
+
+
+def setup(app):
+    from sphinx.util import inspect
+
+    wrapped_isfunc = inspect.isfunction
+
+    def isfunc(obj):
+        type_name = str(type(obj))
+        if "nanobind.nb_method" in type_name or "nanobind.nb_func" in type_name:
+            return True
+        return wrapped_isfunc(obj)
+
+    inspect.isfunction = isfunc
+
+
+# -- Options for LaTeX output ------------------------------------------------
+
+latex_documents = [(main_doc, "MLX.tex", "MLX Documentation", author, "manual")]
+latex_elements = {
+    "preamble": r"""
+    \usepackage{enumitem}
+    \setlistdepth{5}
+    \setlist[itemize,1]{label=$\bullet$}
+    \setlist[itemize,2]{label=$\bullet$}
+    \setlist[itemize,3]{label=$\bullet$}
+    \setlist[itemize,4]{label=$\bullet$}
+    \setlist[itemize,5]{label=$\bullet$}
+    \renewlist{itemize}{itemize}{5}
+""",
+}

docs/src/cpp/ops.rst

@@ -3,4 +3,5 @@
 Operations
 ==========
 
-
+.. doxygengroup:: ops
+   :content-only:

docs/src/dev/custom_metal_kernels.rst

@@ -0,0 +1,413 @@
+Custom Metal Kernels
+====================
+
+MLX supports writing custom Metal kernels through the Python and C++ APIs.
+
+Simple Example
+--------------
+
+Let's write a custom kernel that computes ``exp`` elementwise:
+
+.. code-block:: python
+
+  def exp_elementwise(a: mx.array):
+      source = """
+          uint elem = thread_position_in_grid.x;
+          T tmp = inp[elem];
+          out[elem] = metal::exp(tmp);
+      """
+
+      kernel = mx.fast.metal_kernel(
+          name="myexp",
+          source=source,
+      )
+      outputs = kernel(
+          inputs={"inp": a},
+          template={"T": mx.float32},
+          grid=(a.size, 1, 1),
+          threadgroup=(256, 1, 1),
+          output_shapes={"out": a.shape},
+          output_dtypes={"out": a.dtype},
+      )
+      return outputs["out"]
+
+  a = mx.random.normal(shape=(4, 16)).astype(mx.float16)
+  b = exp_elementwise(a)
+  assert mx.allclose(b, mx.exp(a))
+
+.. note::
+    We are only required to pass the body of the Metal kernel in ``source``.
+
+The full function signature will be generated using:
+
+* The keys and shapes/dtypes of ``inputs``
+    In the above, ``a`` is an ``mx.array`` of type ``mx.float16`` and we pass it with the key ``inp``
+    so we will add ``const device float16_t* inp`` to the signature.
+    ``inp_shape``, ``inp_strides`` and ``inp_ndim`` are also added for convenience if they are present
+    in ``source``.
+* The keys and values of ``output_shapes`` and ``output_dtypes``
+    In the above, ``out`` is an ``mx.array`` of type ``mx.float16``
+    so we add ``device float16_t* out``.
+* Template parameters passed using ``template``
+    In the above, ``template={"T": mx.float32}`` adds a template of ``template <typename T>`` to the function
+    and instantiates the template with ``custom_kernel_myexp_float<float>``.
+    Template parameters can be ``mx.core.Dtype``, ``int`` or ``bool``.
+* Metal attributes used in ``source`` such as ``[[thread_position_in_grid]]``
+    These will be added as function arguments.
+    All the attributes defined in Table 5.8 of the `Metal Shading Language Specification <https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf>`_ are supported.
+
+Putting this all together, the generated function signature for ``myexp`` is as follows:
+
+.. code-block:: cpp
+
+  template <typename T>
+  [[kernel]] void custom_kernel_myexp_float(
+    const device float16_t* inp [[buffer(0)]],
+    device float16_t* out [[buffer(1)]],
+    uint3 thread_position_in_grid [[thread_position_in_grid]]) {
+
+          uint elem = thread_position_in_grid.x;
+          T tmp = inp[elem];
+          out[elem] = metal::exp(tmp);
+
+  }
+
+  template [[host_name("custom_kernel_myexp_float")]] [[kernel]] decltype(custom_kernel_myexp_float<float>) custom_kernel_myexp_float<float>;
+
+Passing ``verbose=True`` to ``mx.fast.metal_kernel.__call__`` will print the generated code for debugging purposes.
+
+Using Shape/Strides
+-------------------
+
+``mx.fast.metal_kernel`` supports an argument ``ensure_row_contiguous`` which is ``True`` by default.
+This will copy the ``mx.array`` inputs if needed before the kernel is launched to ensure that the memory layout is row contiguous.
+Generally this makes writing the kernel easier, since we don't have to worry about gaps or the ordering of the dims
+when indexing.
+
+If we want to avoid this copy, ``metal_kernel`` automatically passes ``a_shape``, ``a_strides`` and ``a_ndim`` for each
+input array ``a`` if any are present in ``source``.
+We can then use MLX's built in indexing utils to fetch the right elements for each thread.
+
+Let's convert ``myexp`` above to support arbitrarily strided arrays without relying on a copy from ``ensure_row_contiguous``:
+
+.. code-block:: python
+
+  def exp_elementwise(a: mx.array):
+      source = """
+          uint elem = thread_position_in_grid.x;
+          // Utils from `mlx/backend/metal/kernels/utils.h` are automatically included
+          uint loc = elem_to_loc(elem, inp_shape, inp_strides, inp_ndim);
+          T tmp = inp[loc];
+          // Output arrays are always row contiguous
+          out[elem] = metal::exp(tmp);
+      """
+
+      kernel = mx.fast.metal_kernel(
+          name="myexp_strided",
+          source=source
+      )
+      outputs = kernel(
+          inputs={"inp": a},
+          template={"T": mx.float32},
+          grid=(a.size, 1, 1),
+          threadgroup=(256, 1, 1),
+          output_shapes={"out": a.shape},
+          output_dtypes={"out": a.dtype},
+          ensure_row_contiguous=False,
+      )
+      return outputs["out"]
+
+  a = mx.random.normal(shape=(4, 16)).astype(mx.float16)
+  # make non-contiguous
+  a = a[::2]
+  b = exp_elementwise(a)
+  assert mx.allclose(b, mx.exp(a))
+
+Complex Example
+-----------------------------
+
+Let's implement a more complex example: ``grid_sample`` in ``"bilinear"`` mode.
+
+We'll start with the following MLX implementation using standard ops:
+
+.. code-block:: python
+
+    def grid_sample_ref(x, grid):
+        N, H_in, W_in, _ = x.shape
+        ix = ((grid[..., 0] + 1) * W_in - 1) / 2
+        iy = ((grid[..., 1] + 1) * H_in - 1) / 2
+
+        ix_nw = mx.floor(ix).astype(mx.int32)
+        iy_nw = mx.floor(iy).astype(mx.int32)
+
+        ix_ne = ix_nw + 1
+        iy_ne = iy_nw
+
+        ix_sw = ix_nw
+        iy_sw = iy_nw + 1
+
+        ix_se = ix_nw + 1
+        iy_se = iy_nw + 1
+
+        nw = (ix_se - ix)    * (iy_se - iy)
+        ne = (ix    - ix_sw) * (iy_sw - iy)
+        sw = (ix_ne - ix)    * (iy    - iy_ne)
+        se = (ix    - ix_nw) * (iy    - iy_nw)
+
+        I_nw = x[mx.arange(N)[:, None, None], iy_nw, ix_nw, :]
+        I_ne = x[mx.arange(N)[:, None, None], iy_ne, ix_ne, :]
+        I_sw = x[mx.arange(N)[:, None, None], iy_sw, ix_sw, :]
+        I_se = x[mx.arange(N)[:, None, None], iy_se, ix_se, :]
+
+        mask_nw = (iy_nw >= 0) & (iy_nw <= H_in - 1) & (ix_nw >= 0) & (ix_nw <= W_in - 1)
+        mask_ne = (iy_ne >= 0) & (iy_ne <= H_in - 1) & (ix_ne >= 0) & (ix_ne <= W_in - 1)
+        mask_sw = (iy_sw >= 0) & (iy_sw <= H_in - 1) & (ix_sw >= 0) & (ix_sw <= W_in - 1)
+        mask_se = (iy_se >= 0) & (iy_se <= H_in - 1) & (ix_se >= 0) & (ix_se <= W_in - 1)
+
+        I_nw *= mask_nw[..., None]
+        I_ne *= mask_ne[..., None]
+        I_sw *= mask_sw[..., None]
+        I_se *= mask_se[..., None]
+
+        output = nw[..., None] * I_nw + ne[..., None] * I_ne + sw[..., None] * I_sw + se[..., None] * I_se
+
+        return output
+
+Now let's use ``mx.custom_function`` together with ``mx.fast.metal_kernel``
+to write a fast GPU kernel for both the forward and backward passes.
+
+First we'll implement the forward pass as a fused kernel:
+
+.. code-block:: python
+
+    @mx.custom_function
+    def grid_sample(x, grid):
+
+        assert x.ndim == 4, "`x` must be 4D."
+        assert grid.ndim == 4, "`grid` must be 4D."
+
+        B, _, _, C = x.shape
+        _, gN, gM, D = grid.shape
+        out_shape = (B, gN, gM, C)
+
+        assert D == 2, "Last dim of `grid` must be size 2."
+
+        source = """
+            uint elem = thread_position_in_grid.x;
+            int H = x_shape[1];
+            int W = x_shape[2];
+            int C = x_shape[3];
+            int gH = grid_shape[1];
+            int gW = grid_shape[2];
+
+            int w_stride = C;
+            int h_stride = W * w_stride;
+            int b_stride = H * h_stride;
+
+            uint grid_idx = elem / C * 2;
+            float ix = ((grid[grid_idx] + 1) * W - 1) / 2;
+            float iy = ((grid[grid_idx + 1] + 1) * H - 1) / 2;
+
+            int ix_nw = floor(ix);
+            int iy_nw = floor(iy);
+
+            int ix_ne = ix_nw + 1;
+            int iy_ne = iy_nw;
+
+            int ix_sw = ix_nw;
+            int iy_sw = iy_nw + 1;
+
+            int ix_se = ix_nw + 1;
+            int iy_se = iy_nw + 1;
+
+            T nw = (ix_se - ix)    * (iy_se - iy);
+            T ne = (ix    - ix_sw) * (iy_sw - iy);
+            T sw = (ix_ne - ix)    * (iy    - iy_ne);
+            T se = (ix    - ix_nw) * (iy    - iy_nw);
+
+            int batch_idx = elem / C / gH / gW * b_stride;
+            int channel_idx = elem % C;
+            int base_idx = batch_idx + channel_idx;
+
+            T I_nw = x[base_idx + iy_nw * h_stride + ix_nw * w_stride];
+            T I_ne = x[base_idx + iy_ne * h_stride + ix_ne * w_stride];
+            T I_sw = x[base_idx + iy_sw * h_stride + ix_sw * w_stride];
+            T I_se = x[base_idx + iy_se * h_stride + ix_se * w_stride];
+
+            I_nw = iy_nw >= 0 && iy_nw <= H - 1 && ix_nw >= 0 && ix_nw <= W - 1 ? I_nw : 0;
+            I_ne = iy_ne >= 0 && iy_ne <= H - 1 && ix_ne >= 0 && ix_ne <= W - 1 ? I_ne : 0;
+            I_sw = iy_sw >= 0 && iy_sw <= H - 1 && ix_sw >= 0 && ix_sw <= W - 1 ? I_sw : 0;
+            I_se = iy_se >= 0 && iy_se <= H - 1 && ix_se >= 0 && ix_se <= W - 1 ? I_se : 0;
+
+            out[elem] = nw * I_nw + ne * I_ne + sw * I_sw + se * I_se;
+        """
+        kernel = mx.fast.metal_kernel(
+            name="grid_sample",
+            source=source,
+        )
+        outputs = kernel(
+            inputs={"x": x, "grid": grid},
+            template={"T": x.dtype},
+            output_shapes={"out": out_shape},
+            output_dtypes={"out": x.dtype},
+            grid=(np.prod(out_shape), 1, 1),
+            threadgroup=(256, 1, 1),
+        )
+        return outputs["out"]
+
+For a reasonably sized input such as:
+
+.. code-block:: python
+
+    x.shape = (8, 1024, 1024, 64)
+    grid.shape = (8, 256, 256, 2)
+
+On an M1 Max, we see a big performance improvement:
+
+``55.7ms -> 6.7ms => 8x speed up``
+
+Grid Sample VJP
+---------------
+
+Since we decorated ``grid_sample`` with ``mx.custom_function``, we can now define
+its custom vjp transform so MLX can differentiate it.
+
+The backwards pass requires atomically updating ``x_grad``/``grid_grad`` and so
+requires a few extra ``mx.fast.metal_kernel`` features:
+
+* ``init_value=0``
+    Initialize all of the kernel's outputs to this value before it runs. This allows us to update only part of the output arrays with the kernel.
+
+* ``atomic_outputs=True``
+    Designate all of the kernel outputs as ``atomic`` in the function signature. 
+    This means we can use Metal's ``atomic`` features to simultaneously update the ``x_grad`` and ``grid_grad`` arrays from multiple threadgroups. 
+    See section 6.15 of the `Metal Shading Language Specification <https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf>`_ for more details.
+
+We can then implement the backwards pass as follows:
+
+.. code-block:: python
+
+    @grid_sample.vjp
+    def grid_sample_vjp(primals, cotangent, _):
+        x, grid = primals
+        B, _, _, C = x.shape
+        _, gN, gM, D = grid.shape
+
+        assert D == 2, "Last dim of `grid` must be size 2."
+
+        source = """
+            uint elem = thread_position_in_grid.x;
+            int H = x_shape[1];
+            int W = x_shape[2];
+            int C = x_shape[3];
+            // Pad C to the nearest larger simdgroup size multiple
+            int C_padded = ceildiv(C, threads_per_simdgroup) * threads_per_simdgroup;
+
+            int gH = grid_shape[1];
+            int gW = grid_shape[2];
+
+            int w_stride = C;
+            int h_stride = W * w_stride;
+            int b_stride = H * h_stride;
+
+            uint grid_idx = elem / C_padded * 2;
+            float ix = ((grid[grid_idx] + 1) * W - 1) / 2;
+            float iy = ((grid[grid_idx + 1] + 1) * H - 1) / 2;
+
+            int ix_nw = floor(ix);
+            int iy_nw = floor(iy);
+
+            int ix_ne = ix_nw + 1;
+            int iy_ne = iy_nw;
+
+            int ix_sw = ix_nw;
+            int iy_sw = iy_nw + 1;
+
+            int ix_se = ix_nw + 1;
+            int iy_se = iy_nw + 1;
+
+            T nw = (ix_se - ix)    * (iy_se - iy);
+            T ne = (ix    - ix_sw) * (iy_sw - iy);
+            T sw = (ix_ne - ix)    * (iy    - iy_ne);
+            T se = (ix    - ix_nw) * (iy    - iy_nw);
+
+            int batch_idx = elem / C_padded / gH / gW * b_stride;
+            int channel_idx = elem % C_padded;
+            int base_idx = batch_idx + channel_idx;
+
+            T gix = T(0);
+            T giy = T(0);
+            if (channel_idx < C) {
+                int cot_index = elem / C_padded * C + channel_idx;
+                T cot = cotangent[cot_index];
+                if (iy_nw >= 0 && iy_nw <= H - 1 && ix_nw >= 0 && ix_nw <= W - 1) {
+                    int offset = base_idx + iy_nw * h_stride + ix_nw * w_stride;
+                    atomic_fetch_add_explicit(&x_grad[offset], nw * cot, memory_order_relaxed);
+
+                    T I_nw = x[offset];
+                    gix -= I_nw * (iy_se - iy) * cot;
+                    giy -= I_nw * (ix_se - ix) * cot;
+                }
+                if (iy_ne >= 0 && iy_ne <= H - 1 && ix_ne >= 0 && ix_ne <= W - 1) {
+                    int offset = base_idx + iy_ne * h_stride + ix_ne * w_stride;
+                    atomic_fetch_add_explicit(&x_grad[offset], ne * cot, memory_order_relaxed);
+
+                    T I_ne = x[offset];
+                    gix += I_ne * (iy_sw - iy) * cot;
+                    giy -= I_ne * (ix - ix_sw) * cot;
+                }
+                if (iy_sw >= 0 && iy_sw <= H - 1 && ix_sw >= 0 && ix_sw <= W - 1) {
+                    int offset = base_idx + iy_sw * h_stride + ix_sw * w_stride;
+                    atomic_fetch_add_explicit(&x_grad[offset], sw * cot, memory_order_relaxed);
+
+                    T I_sw = x[offset];
+                    gix -= I_sw * (iy - iy_ne) * cot;
+                    giy += I_sw * (ix_ne - ix) * cot;
+                }
+                if (iy_se >= 0 && iy_se <= H - 1 && ix_se >= 0 && ix_se <= W - 1) {
+                    int offset = base_idx + iy_se * h_stride + ix_se * w_stride;
+                    atomic_fetch_add_explicit(&x_grad[offset], se * cot, memory_order_relaxed);
+
+                    T I_se = x[offset];
+                    gix += I_se * (iy - iy_nw) * cot;
+                    giy += I_se * (ix - ix_nw) * cot;
+                }
+            }
+
+            T gix_mult = W / 2;
+            T giy_mult = H / 2;
+
+            // Reduce across each simdgroup first.
+            // This is much faster than relying purely on atomics.
+            gix = simd_sum(gix);
+            giy = simd_sum(giy);
+
+            if (thread_index_in_simdgroup == 0) {
+                atomic_fetch_add_explicit(&grid_grad[grid_idx], gix * gix_mult, memory_order_relaxed);
+                atomic_fetch_add_explicit(&grid_grad[grid_idx + 1], giy * giy_mult, memory_order_relaxed);
+            }
+        """
+        kernel = mx.fast.metal_kernel(
+            name="grid_sample_grad",
+            source=source,
+            atomic_outputs=True,
+        )
+        # pad the output channels to simd group size
+        # so that our `simd_sum`s don't overlap.
+        simdgroup_size = 32
+        C_padded = (C + simdgroup_size - 1) // simdgroup_size * simdgroup_size
+        grid_size = B * gN * gM * C_padded
+        outputs = kernel(
+            inputs={"x": x, "grid": grid, "cotangent": cotangent},
+            template={"T": x.dtype},
+            output_shapes={"x_grad": x.shape, "grid_grad": grid.shape},
+            output_dtypes={"x_grad": x.dtype, "grid_grad": x.dtype},
+            grid=(grid_size, 1, 1),
+            threadgroup=(256, 1, 1),
+            init_value=0,
+        )
+        return outputs["x_grad"], outputs["grid_grad"]
+
+There's an even larger speed up for the vjp:
+
+``676.4ms -> 16.7ms => 40x speed up``

docs/src/dev/extensions.rst

@@ -1,24 +1,16 @@
-Developer Documentation
-=======================
+Custom Extensions in MLX
+========================
 
-MLX provides a open and flexible backend to which users may add operations 
-and specialized implementations without much hassle. While the library supplies
-efficient operations that can be used and composed for any number of 
-applications, there may arise cases where new functionalities or highly 
-optimized implementations are needed. For such cases, you may design and 
-implement your own operations that link to and build on top of :mod:`mlx.core`.
-We will introduce the inner-workings of MLX and go over a simple example to 
-learn the steps involved in adding new operations to MLX with your own CPU 
-and GPU implementations. 
+You can extend MLX with custom operations on the CPU or GPU. This guide
+explains how to do that with a simple example.
 
 Introducing the Example
 -----------------------
 
-Let's say that you would like an operation that takes in two arrays, 
-``x`` and ``y``, scales them both by some coefficients ``alpha`` and ``beta``
-respectively, and then adds them together to get the result 
-``z = alpha * x + beta * y``. Well, you can very easily do that by just 
-writing out a function as follows:
+Let's say you would like an operation that takes in two arrays, ``x`` and
+``y``, scales them both by coefficients ``alpha`` and ``beta`` respectively,
+and then adds them together to get the result ``z = alpha * x + beta * y``.
+You can do that in MLX directly:
 
 .. code-block:: python
 
@@ -27,44 +19,35 @@ writing out a function as follows:
     def simple_axpby(x: mx.array, y: mx.array, alpha: float, beta: float) -> mx.array:
         return alpha * x + beta * y
 
-This function performs that operation while leaving the implementations and 
-differentiation to MLX. 
+This function performs that operation while leaving the implementation and
+function transformations to MLX.
 
-However, you work with vector math libraries often and realize that the 
-``axpby`` routine defines the same operation ``Y = (alpha * X) + (beta * Y)``. 
-You would really like the part of your applications that does this operation 
-on the CPU to be very fast - so you decide that you want it to rely on the 
-``axpby`` routine provided by the Accelerate_ framework. Continuing to impose 
-our assumptions on to you, let's also assume that you want to learn how add 
-your own implementation for the gradients of your new operation while going 
-over the ins-and-outs of the MLX framework. 
+However you may need to customize the underlying implementation, perhaps to
+make it faster or for custom differentiation. In this tutorial we will go
+through adding custom extensions. It will cover:
 
-Well, what a coincidence! You are in the right place. Over the course of this 
-example, we will learn:
-
-* The structure of the MLX library from the frontend API to the backend implementations.
-* How to implement your own CPU backend that redirects to Accelerate_ when appropriate (and a fallback if needed).
-* How to implement your own GPU implementation using metal.
-* How to add your own ``vjp`` and ``jvp``.
-* How to build your implementations, link them to MLX, and bind them to python.
+* The structure of the MLX library.
+* Implementing a CPU operation that redirects to Accelerate_ when appropriate.
+* Implementing a GPU operation using metal.
+* Adding the ``vjp`` and ``jvp`` function transformation.
+* Building a custom extension and binding it to python.
 
 Operations and Primitives
 -------------------------
 
-In one sentence, operations in MLX build the computation graph, and primitives 
-provide the rules for evaluation and transformations of said graph. Let's start 
-by discussing operations in more detail. 
+Operations in MLX build the computation graph. Primitives provide the rules for
+evaluating and transforming the graph. Let's start by discussing operations in
+more detail.
 
 Operations
 ^^^^^^^^^^^
 
-Operations are the frontend functions that operate on arrays. They are defined 
-in the C++ API (:ref:`cpp_ops`) and then we provide bindings to these 
-operations in the Python API (:ref:`ops`). 
+Operations are the front-end functions that operate on arrays. They are defined
+in the C++ API (:ref:`cpp_ops`), and the Python API (:ref:`ops`) binds them.
 
-We would like an operation, :meth:`axpby` that takes in two arrays ``x`` and ``y``,
-and two scalars, ``alpha`` and ``beta``. This is how we would define it in the 
-C++ API:
+We would like an operation, :meth:`axpby` that takes in two arrays ``x`` and
+``y``, and two scalars, ``alpha`` and ``beta``. This is how to define it in
+C++:
 
 .. code-block:: C++
 
@@ -83,10 +66,7 @@ C++ API:
         StreamOrDevice s = {} // Stream on which to schedule the operation
     );
 
-
-This operation itself can call other operations within it if needed. So, the 
-simplest way to go about implementing this operation would be do so in terms 
-of existing operations. 
+The simplest way to this operation is in terms of existing operations:
 
 .. code-block:: C++
 
@@ -100,25 +80,23 @@ of existing operations.
         // Scale x and y on the provided stream
         auto ax = multiply(array(alpha), x, s);
         auto by = multiply(array(beta), y, s);
-        
+
         // Add and return
         return add(ax, by, s);
     }
 
-However, as we discussed earlier, this is not our goal. The operations themselves 
-do not contain the implementations that act on the data, nor do they contain the
-rules of transformations. Rather, they are an easy to use interface that build 
-on top of the building blocks we call :class:`Primitive`. 
+The operations themselves do not contain the implementations that act on the
+data, nor do they contain the rules of transformations. Rather, they are an
+easy to use interface that use :class:`Primitive` building blocks.
 
 Primitives
 ^^^^^^^^^^^
 
-A :class:`Primitive` is part of the computation graph of an :class:`array`. It 
-defines how to create an output given a set of input :class:`array` . Further,
-a :class:`Primitive` is a class that contains rules on how it is evaluated 
-on the CPU or GPU, and how it acts under transformations such as ``vjp`` and 
-``jvp``. These words on their own can be a bit abstract, so lets take a step 
-back and go to our example to give ourselves a more concrete image. 
+A :class:`Primitive` is part of the computation graph of an :class:`array`. It
+defines how to create outputs arrays given a input arrays. Further, a
+:class:`Primitive` has methods to run on the CPU or GPU and for function
+transformations such as ``vjp`` and ``jvp``.  Lets go back to our example to be
+more concrete:
 
 .. code-block:: C++
 
@@ -134,11 +112,15 @@ back and go to our example to give ourselves a more concrete image.
         * To avoid unnecessary allocations, the evaluation function
         * is responsible for allocating space for the array.
         */
-        void eval_cpu(const std::vector<array>& inputs, array& out) override;
-        void eval_gpu(const std::vector<array>& inputs, array& out) override;
+        void eval_cpu(
+            const std::vector<array>& inputs,
+            std::vector<array>& outputs) override;
+        void eval_gpu(
+            const std::vector<array>& inputs,
+            std::vector<array>& outputs) override;
 
         /** The Jacobian-vector product. */
-        array jvp(
+        std::vector<array> jvp(
             const std::vector<array>& primals,
             const std::vector<array>& tangents,
             const std::vector<int>& argnums) override;
@@ -147,7 +129,8 @@ back and go to our example to give ourselves a more concrete image.
         std::vector<array> vjp(
             const std::vector<array>& primals,
             const array& cotan,
-            const std::vector<int>& argnums) override;
+            const std::vector<int>& argnums,
+            const std::vector<array>& outputs) override;
 
         /**
         * The primitive must know how to vectorize itself across
@@ -155,7 +138,7 @@ back and go to our example to give ourselves a more concrete image.
         * representing the vectorized computation and the axis which
         * corresponds to the output vectorized dimension.
         */
-        std::pair<array, int> vmap(
+        virtual std::pair<std::vector<array>, std::vector<int>> vmap(
             const std::vector<array>& inputs,
             const std::vector<int>& axes) override;
 
@@ -175,22 +158,22 @@ back and go to our example to give ourselves a more concrete image.
         void eval(const std::vector<array>& inputs, array& out);
     };
 
-The :class:`Axpby` class derives from the base :class:`Primitive` class and 
-follows the above demonstrated interface. :class:`Axpby` treats ``alpha`` and 
-``beta`` as parameters. It then provides implementations of how the array ``out`` 
-is produced given ``inputs`` through :meth:`Axpby::eval_cpu` and 
-:meth:`Axpby::eval_gpu`. Further, it provides rules of transformations in 
-:meth:`Axpby::jvp`, :meth:`Axpby::vjp`, and :meth:`Axpby::vmap`. 
+The :class:`Axpby` class derives from the base :class:`Primitive` class. The
+:class:`Axpby` treats ``alpha`` and ``beta`` as parameters. It then provides
+implementations of how the output array is produced given the inputs through
+:meth:`Axpby::eval_cpu` and :meth:`Axpby::eval_gpu`. It also provides rules
+of transformations in :meth:`Axpby::jvp`, :meth:`Axpby::vjp`, and
+:meth:`Axpby::vmap`.
 
-Using the Primitives
-^^^^^^^^^^^^^^^^^^^^^
+Using the Primitive
+^^^^^^^^^^^^^^^^^^^
 
-Operations can use this :class:`Primitive` to add a new :class:`array` to 
-the computation graph. An :class:`array` can be constructed by providing its 
-data type, shape, the :class:`Primitive` that computes it, and the 
-:class:`array` inputs that are passed to the primitive.
+Operations can use this :class:`Primitive` to add a new :class:`array` to the
+computation graph. An :class:`array` can be constructed by providing its data
+type, shape, the :class:`Primitive` that computes it, and the :class:`array`
+inputs that are passed to the primitive.
 
-Let's re-implement our operation now in terms of our :class:`Axpby` primitive.
+Let's reimplement our operation now in terms of our :class:`Axpby` primitive.
 
 .. code-block:: C++
 
@@ -223,7 +206,7 @@ Let's re-implement our operation now in terms of our :class:`Axpby` primitive.
             /* const std::vector<int>& shape = */ out_shape,
             /* Dtype dtype = */ out_dtype,
             /* std::unique_ptr<Primitive> primitive = */
-            std::make_unique<Axpby>(to_stream(s), alpha, beta),
+            std::make_shared<Axpby>(to_stream(s), alpha, beta),
             /* const std::vector<array>& inputs = */ broadcasted_inputs);
     }
 
@@ -238,27 +221,26 @@ This operation now handles the following:
 Implementing the Primitive
 --------------------------
 
-No computation happens when we call the operation alone. In effect, the 
-operation only builds the computation graph. When we evaluate the output 
-array, MLX schedules the execution of the computation graph, and calls
-:meth:`Axpby::eval_cpu` or :meth:`Axpby::eval_gpu` depending on the 
-stream/device specified by the user. 
+No computation happens when we call the operation alone. The operation only
+builds the computation graph. When we evaluate the output array, MLX schedules
+the execution of the computation graph, and calls :meth:`Axpby::eval_cpu` or
+:meth:`Axpby::eval_gpu` depending on the stream/device specified by the user.
 
 .. warning::
     When :meth:`Primitive::eval_cpu` or :meth:`Primitive::eval_gpu` are called,
     no memory has been allocated for the output array. It falls on the implementation
-    of these functions to allocate memory as needed
+    of these functions to allocate memory as needed.
 
-Implementing the CPU Backend
+Implementing the CPU Back-end
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Let's start by trying to implement a naive and generic version of 
-:meth:`Axpby::eval_cpu`. We declared this as a private member function of 
-:class:`Axpby` earlier called :meth:`Axpby::eval`. 
+Let's start by implementing a naive and generic version of
+:meth:`Axpby::eval_cpu`. We declared this as a private member function of
+:class:`Axpby` earlier called :meth:`Axpby::eval`.
 
-Our naive method will go over each element of the output array, find the 
-corresponding input elements of ``x`` and ``y`` and perform the operation 
-pointwise. This is captured in the templated function :meth:`axpby_impl`. 
+Our naive method will go over each element of the output array, find the
+corresponding input elements of ``x`` and ``y`` and perform the operation
+point-wise. This is captured in the templated function :meth:`axpby_impl`.
 
 .. code-block:: C++
 
@@ -296,19 +278,19 @@ pointwise. This is captured in the templated function :meth:`axpby_impl`.
         }
     }
 
-Now, we would like our implementation to be able to do this pointwise operation 
-for all incoming floating point arrays. Accordingly, we add dispatches for 
-``float32``, ``float16``, ``bfloat16`` and ``complex64``. We throw an error 
-if we encounter an unexpected type.
+Our implementation should work for all incoming floating point arrays.
+Accordingly, we add dispatches for ``float32``, ``float16``, ``bfloat16`` and
+``complex64``. We throw an error if we encounter an unexpected type.
 
 .. code-block:: C++
 
     /** Fall back implementation for evaluation on CPU */
-    void Axpby::eval(const std::vector<array>& inputs, array& out) {
-        // Check the inputs (registered in the op while constructing the out array)
-        assert(inputs.size() == 2);
+    void Axpby::eval(
+      const std::vector<array>& inputs,
+      const std::vector<array>& outputs) {
         auto& x = inputs[0];
         auto& y = inputs[1];
+        auto& out = outputs[0];
 
         // Dispatch to the correct dtype
         if (out.dtype() == float32) {
@@ -321,28 +303,26 @@ if we encounter an unexpected type.
             return axpby_impl<complex64_t>(x, y, out, alpha_, beta_);
         } else {
             throw std::runtime_error(
-                "Axpby is only supported for floating point types.");
+                "[Axpby] Only supports floating point types.");
         }
     }
 
-We have a fallback implementation! Now, to do what we are really here to do. 
-Remember we wanted to use the ``axpby`` routine provided by the Accelerate_
-framework? Well, there are 3 complications to keep in mind:
+This is good as a fallback implementation. We can use the ``axpby`` routine
+provided by the Accelerate_ framework for a faster implementation in certain
+cases:
 
 #.  Accelerate does not provide implementations of ``axpby`` for half precision
-    floats. We can only direct to it for ``float32`` types 
-#.  Accelerate assumes the inputs ``x`` and ``y`` are contiguous and all elements
-    have fixed strides between them. Possibly due to broadcasts and transposes, 
-    we aren't guaranteed that the inputs fit this requirement. We can 
-    only direct to Accelerate if both ``x`` and ``y`` are row contiguous or 
-    column contiguous. 
-#.  Accelerate performs the routine ``Y = (alpha * X) + (beta * Y)`` inplace. 
-    MLX expects to write out the answer to a new array. We must copy the elements 
-    of ``y`` into the output array and use that as an input to ``axpby``
+    floats. We can only use it for ``float32`` types.
+#.  Accelerate assumes the inputs ``x`` and ``y`` are contiguous and all
+    elements have fixed strides between them. We only direct to Accelerate
+    if both ``x`` and ``y`` are row contiguous or column contiguous.
+#.  Accelerate performs the routine ``Y = (alpha * X) + (beta * Y)`` in-place.
+    MLX expects to write the output to a new array. We must copy the elements
+    of ``y`` into the output and use that as an input to ``axpby``.
 
-Let's write out an implementation that uses Accelerate in the right conditions. 
-It must simply allocate data for the output, copy elements of ``y`` into it, 
-and then call the :meth:`catlas_saxpby` from accelerate. 
+Let's write an implementation that uses Accelerate in the right conditions.
+It allocates data for the output, copies ``y`` into it, and then calls the
+:func:`catlas_saxpby` from accelerate.
 
 .. code-block:: C++
 
@@ -356,17 +336,7 @@ and then call the :meth:`catlas_saxpby` from accelerate.
         // Accelerate library provides catlas_saxpby which does
         // Y = (alpha * X) + (beta * Y) in place
         // To use it, we first copy the data in y over to the output array
-
-        // This specialization requires both x and y be contiguous in the same mode
-        // i.e: corresponding linear indices in both point to corresponding elements
-        // The data in the output array is allocated to match the strides in y
-        // such that x, y, and out are contiguous in the same mode and
-        // no transposition is needed
-        out.set_data(
-            allocator::malloc_or_wait(y.data_size() * out.itemsize()),
-            y.data_size(),
-            y.strides(),
-            y.flags());
+        out.set_data(allocator::malloc_or_wait(out.nbytes()));
 
         // We then copy over the elements using the contiguous vector specialization
         copy_inplace(y, out, CopyType::Vector);
@@ -389,18 +359,20 @@ and then call the :meth:`catlas_saxpby` from accelerate.
             /* INCY = */ 1);
     }
 
-Great! But what about the inputs that do not fit the criteria for accelerate?
-Luckily, we can always just direct back to :meth:`Axpby::eval`.
-
-With this in mind, lets finally implement our :meth:`Axpby::eval_cpu`.
+For inputs that do not fit the criteria for accelerate, we fall back to
+:meth:`Axpby::eval`. With this in mind, let's finish our
+:meth:`Axpby::eval_cpu`.
 
 .. code-block:: C++
 
     /** Evaluate primitive on CPU using accelerate specializations */
-    void Axpby::eval_cpu(const std::vector<array>& inputs, array& out) {
+    void Axpby::eval_cpu(
+      const std::vector<array>& inputs,
+      const std::vector<array>& outputs) {
         assert(inputs.size() == 2);
         auto& x = inputs[0];
         auto& y = inputs[1];
+        auto& out = outputs[0];
 
         // Accelerate specialization for contiguous single precision float arrays
         if (out.dtype() == float32 &&
@@ -410,35 +382,33 @@ With this in mind, lets finally implement our :meth:`Axpby::eval_cpu`.
             return;
         }
 
-        // Fall back to common backend if specializations are not available
-        eval(inputs, out);
+        // Fall back to common back-end if specializations are not available
+        eval(inputs, outputs);
     }
 
-We have now hit a milestone! Just this much is enough to run the operation 
-:meth:`axpby` on a CPU stream! 
+Just this much is enough to run the operation :meth:`axpby` on a CPU stream! If
+you do not plan on running the operation on the GPU or using transforms on
+computation graphs that contain :class:`Axpby`, you can stop implementing the
+primitive here and enjoy the speed-ups you get from the Accelerate library.
 
-If you do not plan on running the operation on the GPU or using transforms on 
-computation graphs that contain :class:`Axpby`, you can stop implementing the 
-primitive here and enjoy the speed-ups you get from the Accelerate library. 
-
-Implementing the GPU Backend
+Implementing the GPU Back-end
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Apple silicon devices address their GPUs using the Metal_ shading language, and 
-all GPU kernels in MLX are written using metal. 
+Apple silicon devices address their GPUs using the Metal_ shading language, and
+GPU kernels in MLX are written using Metal.
 
 .. note::
 
-    Here are some helpful resources if you are new to metal!
+    Here are some helpful resources if you are new to Metal:
 
     * A walkthrough of the metal compute pipeline: `Metal Example`_
     * Documentation for metal shading language: `Metal Specification`_
     * Using metal from C++: `Metal-cpp`_
 
-Let's keep the GPU algorithm simple. We will launch exactly as many threads 
-as there are elements in the output. Each thread will pick the element it needs 
-from ``x`` and ``y``, do the pointwise operation, and then update its assigned 
-element in the output. 
+Let's keep the GPU kernel simple. We will launch exactly as many threads as
+there are elements in the output. Each thread will pick the element it needs
+from ``x`` and ``y``, do the point-wise operation, and update its assigned
+element in the output.
 
 .. code-block:: C++
 
@@ -457,15 +427,14 @@ element in the output.
         // Convert linear indices to offsets in array
         auto x_offset = elem_to_loc(index, shape, x_strides, ndim);
         auto y_offset = elem_to_loc(index, shape, y_strides, ndim);
-        
+
         // Do the operation and update the output
-        out[index] = 
+        out[index] =
             static_cast<T>(alpha) * x[x_offset] + static_cast<T>(beta) * y[y_offset];
     }
 
 We then need to instantiate this template for all floating point types and give
-each instantiation a unique host name so we can identify the right kernel for 
-each data type. 
+each instantiation a unique host name so we can identify it.
 
 .. code-block:: C++
 
@@ -488,29 +457,21 @@ each data type.
     instantiate_axpby(bfloat16, bfloat16_t);
     instantiate_axpby(complex64, complex64_t);
 
-This kernel will be compiled into a metal library ``mlx_ext.metallib`` as we 
-will see later in :ref:`Building with CMake`. In the following example, we 
-assume that the library ``mlx_ext.metallib`` will always be co-located with 
-the executable/ shared-library calling the :meth:`register_library` function. 
-The :meth:`register_library` function takes the library's name and potential 
-path (or in this case, a function that can produce the path of the metal 
-library) and tries to load that library if it hasn't already been registered 
-by the relevant static :class:`mlx::core::metal::Device` object. This is why, 
-it is important to package your C++ library with the metal library. We will 
-go over this process in more detail later. 
-
-The logic to determine the kernel, set the inputs, resolve the grid dimensions 
-and dispatch it to the GPU are contained in :meth:`Axpby::eval_gpu` as shown 
+The logic to determine the kernel, set the inputs, resolve the grid dimensions,
+and dispatch to the GPU are contained in :meth:`Axpby::eval_gpu` as shown
 below.
 
 .. code-block:: C++
 
     /** Evaluate primitive on GPU */
-    void Axpby::eval_gpu(const std::vector<array>& inputs, array& out) {
+    void Axpby::eval_gpu(
+      const std::vector<array>& inputs,
+      std::vector<array>& outputs) {
         // Prepare inputs
         assert(inputs.size() == 2);
         auto& x = inputs[0];
         auto& y = inputs[1];
+        auto& out = outputs[0];
 
         // Each primitive carries the stream it should execute on
         // and each stream carries its device identifiers
@@ -518,22 +479,21 @@ below.
         // We get the needed metal device using the stream
         auto& d = metal::device(s.device);
 
-        // Allocate output memory 
+        // Allocate output memory
         out.set_data(allocator::malloc_or_wait(out.nbytes()));
 
-        // Resolve name of kernel (corresponds to axpby.metal)
+        // Resolve name of kernel
         std::ostringstream kname;
         kname << "axpby_" << "general_" << type_to_name(out);
 
-        // Make sure the metal library is available and look for it
-        // in the same folder as this executable if needed
-        d.register_library("mlx_ext", metal::get_colocated_mtllib_path);
+        // Make sure the metal library is available
+        d.register_library("mlx_ext");
 
         // Make a kernel from this metal library
         auto kernel = d.get_kernel(kname.str(), "mlx_ext");
 
         // Prepare to encode kernel
-        auto compute_encoder = d.get_command_encoder(s.index);
+        auto& compute_encoder = d.get_command_encoder(s.index);
         compute_encoder->setComputePipelineState(kernel);
 
         // Kernel parameters are registered with buffer indices corresponding to
@@ -542,17 +502,17 @@ below.
         size_t nelem = out.size();
 
         // Encode input arrays to kernel
-        set_array_buffer(compute_encoder, x, 0);
-        set_array_buffer(compute_encoder, y, 1);
+        compute_encoder.set_input_array(x, 0);
+        compute_encoder.set_input_array(y, 1);
 
         // Encode output arrays to kernel
-        set_array_buffer(compute_encoder, out, 2);
+        compute_encoder.set_output_array(out, 2);
 
         // Encode alpha and beta
         compute_encoder->setBytes(&alpha_, sizeof(float), 3);
         compute_encoder->setBytes(&beta_, sizeof(float), 4);
 
-        // Encode shape, strides and ndim 
+        // Encode shape, strides and ndim
         compute_encoder->setBytes(x.shape().data(), ndim * sizeof(int), 5);
         compute_encoder->setBytes(x.strides().data(), ndim * sizeof(size_t), 6);
         compute_encoder->setBytes(y.strides().data(), ndim * sizeof(size_t), 7);
@@ -570,33 +530,30 @@ below.
 
         // Launch the grid with the given number of threads divided among
         // the given threadgroups
-        compute_encoder->dispatchThreads(grid_dims, group_dims);
+        compute_encoder.dispatchThreads(grid_dims, group_dims);
     }
 
 We can now call the :meth:`axpby` operation on both the CPU and the GPU!
 
-A few things to note about MLX and metal before moving on. MLX keeps track 
-of the active ``compute_encoder``. We rely on :meth:`d.get_command_encoder` 
-to give us the active metal compute command encoder instead of building a 
-new one and calling :meth:`compute_encoder->end_encoding` at the end. 
-MLX keeps adding kernels (compute pipelines) to the active command encoder 
-until some specified limit is hit or the compute encoder needs to be flushed 
-for synchronization. MLX also handles enqueuing and committing the associated 
-command buffers as needed. We suggest taking a deeper dive into 
-:class:`metal::Device` if you would like to study this routine further.
+A few things to note about MLX and Metal before moving on. MLX keeps track of
+the active ``command_buffer`` and the ``MTLCommandBuffer`` to which it is
+associated. We rely on :meth:`d.get_command_encoder` to give us the active
+metal compute command encoder instead of building a new one and calling
+:meth:`compute_encoder->end_encoding` at the end. MLX adds kernels (compute
+pipelines) to the active command buffer until some specified limit is hit or
+the command buffer needs to be flushed for synchronization.
 
 Primitive Transforms
 ^^^^^^^^^^^^^^^^^^^^^
 
-Now that we have come this far, let's also learn how to add implementations to 
-transformations in a :class:`Primitive`. These transformations can be built on 
-top of our operations, including the one we just defined now. Which then gives 
-us the following :meth:`Axpby::jvp` and :meth:`Axpby::vjp` implementations.
+Next, let's add implementations for transformations in a :class:`Primitive`.
+These transformations can be built on top of other operations, including the
+one we just defined:
 
 .. code-block:: C++
 
     /** The Jacobian-vector product. */
-    array Axpby::jvp(
+    std::vector<array> Axpby::jvp(
             const std::vector<array>& primals,
             const std::vector<array>& tangents,
             const std::vector<int>& argnums) {
@@ -611,12 +568,12 @@ us the following :meth:`Axpby::jvp` and :meth:`Axpby::vjp` implementations.
         if (argnums.size() > 1) {
             auto scale = argnums[0] == 0 ? alpha_ : beta_;
             auto scale_arr = array(scale, tangents[0].dtype());
-            return multiply(scale_arr, tangents[0], stream());
+            return {multiply(scale_arr, tangents[0], stream())};
         }
         // If, argnums = {0, 1}, we take contributions from both
         // which gives us jvp = tangent_x * alpha + tangent_y * beta
         else {
-            return axpby(tangents[0], tangents[1], alpha_, beta_, stream());
+            return {axpby(tangents[0], tangents[1], alpha_, beta_, stream())};
         }
     }
 
@@ -625,34 +582,35 @@ us the following :meth:`Axpby::jvp` and :meth:`Axpby::vjp` implementations.
     /** The vector-Jacobian product. */
     std::vector<array> Axpby::vjp(
             const std::vector<array>& primals,
-            const array& cotan,
-            const std::vector<int>& argnums) {
+            const std::vector<array>& cotangents,
+            const std::vector<int>& argnums,
+            const std::vector<int>& /* unused */) {
         // Reverse mode diff
         std::vector<array> vjps;
         for (auto arg : argnums) {
             auto scale = arg == 0 ? alpha_ : beta_;
-            auto scale_arr = array(scale, cotan.dtype());
-            vjps.push_back(multiply(scale_arr, cotan, stream()));
+            auto scale_arr = array(scale, cotangents[0].dtype());
+            vjps.push_back(multiply(scale_arr, cotangents[0], stream()));
         }
         return vjps;
     }
 
-Finally, you need not have a transformation fully defined to start using your 
-own :class:`Primitive`.
+Note, a transformation does not need to be fully defined to start using
+the :class:`Primitive`.
 
 .. code-block:: C++
 
     /** Vectorize primitive along given axis */
-    std::pair<array, int> Axpby::vmap(
+    std::pair<std::vector<array>, std::vector<int>> Axpby::vmap(
             const std::vector<array>& inputs,
             const std::vector<int>& axes) {
-        throw std::runtime_error("Axpby has no vmap implementation.");
+        throw std::runtime_error("[Axpby] vmap not implemented.");
     }
 
 Building and Binding
 --------------------
 
-Let's look at the overall directory structure first. 
+Let's look at the overall directory structure first.
 
 | extensions
 | ├── axpby
@@ -666,40 +624,39 @@ Let's look at the overall directory structure first.
 | └── setup.py
 
 * ``extensions/axpby/`` defines the C++ extension library
-* ``extensions/mlx_sample_extensions`` sets out the structure for the 
-  associated python package
-* ``extensions/bindings.cpp`` provides python bindings for our operation
-* ``extensions/CMakeLists.txt`` holds CMake rules to build the library and 
-  python bindings
+* ``extensions/mlx_sample_extensions`` sets out the structure for the
+  associated Python package
+* ``extensions/bindings.cpp`` provides Python bindings for our operation
+* ``extensions/CMakeLists.txt`` holds CMake rules to build the library and
+  Python bindings
 * ``extensions/setup.py`` holds the ``setuptools`` rules to build and install
-  the python package
+  the Python package
 
 Binding to Python
 ^^^^^^^^^^^^^^^^^^
 
-We use PyBind11_ to build a Python API for the C++ library. Since bindings 
-for all needed components such as `mlx.core.array`, `mlx.core.stream`, etc. 
-are already provided, adding our :meth:`axpby` becomes very simple!
+We use nanobind_ to build a Python API for the C++ library. Since bindings for
+components such as :class:`mlx.core.array`, :class:`mlx.core.stream`, etc. are
+already provided, adding our :meth:`axpby` is simple.
 
 .. code-block:: C++
 
-    PYBIND11_MODULE(mlx_sample_extensions, m) {
-        m.doc() = "Sample C++ and metal extensions for MLX";
+   NB_MODULE(_ext, m) {
+        m.doc() = "Sample extension for MLX";
 
         m.def(
             "axpby",
             &axpby,
             "x"_a,
             "y"_a,
-            py::pos_only(),
             "alpha"_a,
             "beta"_a,
-            py::kw_only(),
-            "stream"_a = py::none(),
-            R"pbdoc(
+            nb::kw_only(),
+            "stream"_a = nb::none(),
+            R"(
                 Scale and sum two vectors element-wise
                 ``z = alpha * x + beta * y``
-                
+
                 Follows numpy style broadcasting between ``x`` and ``y``
                 Inputs are upcasted to floats if needed
 
@@ -711,17 +668,17 @@ are already provided, adding our :meth:`axpby` becomes very simple!
 
                 Returns:
                     array: ``alpha * x + beta * y``
-            )pbdoc");
+            )");
     }
 
-Most of the complexity in the above example comes from additional bells and 
+Most of the complexity in the above example comes from additional bells and
 whistles such as the literal names and doc-strings.
 
 .. warning::
 
-    :mod:`mlx.core` needs to be imported before importing 
-    :mod:`mlx_sample_extensions` as defined by the pybind11 module above to 
-    ensure that the casters for :mod:`mlx.core` components like 
+    :mod:`mlx.core` must be imported before importing
+    :mod:`mlx_sample_extensions` as defined by the nanobind module above to
+    ensure that the casters for :mod:`mlx.core` components like
     :class:`mlx.core.array` are available.
 
 .. _Building with CMake:
@@ -729,8 +686,8 @@ whistles such as the literal names and doc-strings.
 Building with CMake
 ^^^^^^^^^^^^^^^^^^^^
 
-Building the C++ extension library itself is simple, it only requires that you 
-``find_package(MLX CONFIG)`` and then link it to your library. 
+Building the C++ extension library only requires that you ``find_package(MLX
+CONFIG)`` and then link it to your library.
 
 .. code-block:: cmake
 
@@ -752,12 +709,12 @@ Building the C++ extension library itself is simple, it only requires that you
     # Link to mlx
     target_link_libraries(mlx_ext PUBLIC mlx)
 
-We also need to build the attached metal library. For convenience, we provide a 
-:meth:`mlx_build_metallib` function that builds a ``.metallib`` target given 
-sources, headers, destinations, etc. (defined in ``cmake/extension.cmake`` and 
-automatically imported with MLX package). 
+We also need to build the attached Metal library. For convenience, we provide a
+:meth:`mlx_build_metallib` function that builds a ``.metallib`` target given
+sources, headers, destinations, etc. (defined in ``cmake/extension.cmake`` and
+automatically imported with MLX package).
 
-Here is what that looks like in practice!
+Here is what that looks like in practice:
 
 .. code-block:: cmake
 
@@ -779,27 +736,29 @@ Here is what that looks like in practice!
 
     endif()
 
-Finally, we build the Pybind11_ bindings
+Finally, we build the nanobind_ bindings
 
 .. code-block:: cmake
 
-    pybind11_add_module(
-        mlx_sample_extensions
-        ${CMAKE_CURRENT_LIST_DIR}/bindings.cpp
+    nanobind_add_module(
+      _ext
+      NB_STATIC STABLE_ABI LTO NOMINSIZE
+      NB_DOMAIN mlx
+      ${CMAKE_CURRENT_LIST_DIR}/bindings.cpp
     )
-    target_link_libraries(mlx_sample_extensions PRIVATE mlx_ext)
+    target_link_libraries(_ext PRIVATE mlx_ext)
 
     if(BUILD_SHARED_LIBS)
-        target_link_options(mlx_sample_extensions PRIVATE -Wl,-rpath,@loader_path)
+      target_link_options(_ext PRIVATE -Wl,-rpath,@loader_path)
     endif()
 
 Building with ``setuptools``
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Once we have set out the CMake build rules as described above, we can use the
-build utilities defined in :mod:`mlx.extension` for a simple build process. 
+build utilities defined in :mod:`mlx.extension`:
 
-.. code-block:: python 
+.. code-block:: python
 
     from mlx import extension
     from setuptools import setup
@@ -809,48 +768,50 @@ build utilities defined in :mod:`mlx.extension` for a simple build process.
             name="mlx_sample_extensions",
             version="0.0.0",
             description="Sample C++ and Metal extensions for MLX primitives.",
-            ext_modules=[extension.CMakeExtension("mlx_sample_extensions")],
+            ext_modules=[extension.CMakeExtension("mlx_sample_extensions._ext")],
             cmdclass={"build_ext": extension.CMakeBuild},
-            packages = ["mlx_sample_extensions"],
-            package_dir = {"": "mlx_sample_extensions"},
-            package_data = {"mlx_sample_extensions" : ["*.so", "*.dylib", "*.metallib"]},
+            packages=["mlx_sample_extensions"],
+            package_data={"mlx_sample_extensions": ["*.so", "*.dylib", "*.metallib"]},
+            extras_require={"dev":[]},
             zip_safe=False,
-            python_requires=">=3.7",
+            python_requires=">=3.8",
         )
 
 .. note::
     We treat ``extensions/mlx_sample_extensions`` as the package directory
     even though it only contains a ``__init__.py`` to ensure the following:
-    
-    * :mod:`mlx.core` is always imported before importing  :mod:`mlx_sample_extensions`
-    * The C++ extension library and the metal library are co-located with the python 
-      bindings and copied together if the package is installed 
 
-You can build inplace for development using
+    * :mod:`mlx.core` must be imported before importing :mod:`_ext`
+    * The C++ extension library and the metal library are co-located with the python
+      bindings and copied together if the package is installed
+
+To build the package, first install the build dependencies with ``pip install
+-r requirements.txt``.  You can then build inplace for development using
 ``python setup.py build_ext -j8 --inplace`` (in ``extensions/``)
 
-This will result in a directory structure as follows:
+This results in the directory structure:
 
 | extensions
 | ├── mlx_sample_extensions
 | │   ├── __init__.py
 | │   ├── libmlx_ext.dylib # C++ extension library
 | │   ├── mlx_ext.metallib # Metal library
-| │   └── mlx_sample_extensions.cpython-3x-darwin.so # Python Binding
+| │   └── _ext.cpython-3x-darwin.so # Python Binding
 | ...
 
-When you try to install using the command ``python -m pip install .`` 
-(in ``extensions/``), the package will be installed with the same structure as 
-``extensions/mlx_sample_extensions`` and the C++ and metal library will be 
-copied along with the python binding since they are specified as ``package_data``.
+When you try to install using the command ``python -m pip install .`` (in
+``extensions/``), the package will be installed with the same structure as
+``extensions/mlx_sample_extensions`` and the C++ and Metal library will be
+copied along with the Python binding since they are specified as
+``package_data``.
 
 Usage
 -----
 
-After installing the extension as described above, you should be able to simply 
-import the python package and play with it as you would any other MLX operation!
+After installing the extension as described above, you should be able to simply
+import the Python package and play with it as you would any other MLX operation.
 
-Let's looks at a simple script and it's results!
+Let's look at a simple script and its results:
 
 .. code-block:: python
 
@@ -863,7 +824,7 @@ Let's looks at a simple script and it's results!
 
     print(f"c shape: {c.shape}")
     print(f"c dtype: {c.dtype}")
-    print(f"c correctness: {mx.all(c == 6.0).item()}")
+    print(f"c correct: {mx.all(c == 6.0).item()}")
 
 Output:
 
@@ -874,12 +835,12 @@ Output:
     c correctness: True
 
 Results
-^^^^^^^^^^^^^^^^
+^^^^^^^
 
-Let's run a quick benchmark and see how our new ``axpby`` operation compares 
-with the naive :meth:`simple_axpby` we defined at first on the CPU. 
+Let's run a quick benchmark and see how our new ``axpby`` operation compares
+with the naive :meth:`simple_axpby` we first defined on the CPU.
 
-.. code-block:: python 
+.. code-block:: python
 
     import mlx.core as mx
     from mlx_sample_extensions import axpby
@@ -898,7 +859,7 @@ with the naive :meth:`simple_axpby` we defined at first on the CPU.
     alpha = 4.0
     beta = 2.0
 
-    mx.eval((x, y))
+    mx.eval(x, y)
 
     def bench(f):
         # Warm up
@@ -919,30 +880,23 @@ with the naive :meth:`simple_axpby` we defined at first on the CPU.
 
     print(f"Simple axpby: {simple_time:.3f} s | Custom axpby: {custom_time:.3f} s")
 
-Results:
+The results are ``Simple axpby: 0.114 s | Custom axpby: 0.109 s``. We see
+modest improvements right away!
 
-.. code-block::
-
-    Simple axpby: 0.114 s | Custom axpby: 0.109 s
-
-We see some modest improvements right away! 
-
-This operation is now good to be used to build other operations, 
-in :class:`mlx.nn.Module` calls, and also as a part of graph 
-transformations like :meth:`grad`!
+This operation is now good to be used to build other operations, in
+:class:`mlx.nn.Module` calls, and also as a part of graph transformations like
+:meth:`grad`.
 
 Scripts
 -------
 
 .. admonition:: Download the code
 
-   The full example code is available in `mlx-examples <code>`_.
-
-.. code: `TODO_LINK/extensions`_
+   The full example code is available in `mlx <https://github.com/ml-explore/mlx/tree/main/examples/extensions/>`_.
 
 .. _Accelerate: https://developer.apple.com/documentation/accelerate/blas?language=objc
 .. _Metal: https://developer.apple.com/documentation/metal?language=objc
 .. _Metal-cpp: https://developer.apple.com/metal/cpp/
 .. _`Metal Specification`: https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf
 .. _`Metal Example`: https://developer.apple.com/documentation/metal/performing_calculations_on_a_gpu?language=objc
-.. _PyBind11: https://pybind11.readthedocs.io/en/stable/
+.. _nanobind: https://nanobind.readthedocs.io/en/latest/

docs/src/dev/metal_debugger.rst

@@ -0,0 +1,68 @@
+Metal Debugger
+==============
+
+.. currentmodule:: mlx.core
+
+Profiling is a key step for performance optimization. You can build MLX with
+the ``MLX_METAL_DEBUG`` option to improve the Metal debugging and
+optimization workflow. The ``MLX_METAL_DEBUG`` debug option:
+
+* Records source during Metal compilation, for later inspection while
+  debugging.
+* Labels Metal objects such as command queues, improving capture readability.
+
+To build with debugging enabled in Python prepend
+``CMAKE_ARGS="-DMLX_METAL_DEBUG=ON"`` to the build call.
+
+The :func:`metal.start_capture` function initiates a capture of all MLX GPU
+work.
+
+.. note::
+
+   To capture a GPU trace you must run the application with
+   ``MTL_CAPTURE_ENABLED=1``.
+
+.. code-block:: python
+
+    import mlx.core as mx
+
+    a = mx.random.uniform(shape=(512, 512))
+    b = mx.random.uniform(shape=(512, 512))
+    mx.eval(a, b)
+
+    trace_file = "mlx_trace.gputrace"
+
+    # Make sure to run with MTL_CAPTURE_ENABLED=1 and
+    # that the path trace_file does not already exist.
+    mx.metal.start_capture(trace_file)
+
+    for _ in range(10):
+      mx.eval(mx.add(a, b))
+
+    mx.metal.stop_capture()
+
+You can open and replay the GPU trace in Xcode. The ``Dependencies`` view
+has a great overview of all operations. Checkout the `Metal debugger
+documentation`_ for more information.
+
+.. image:: ../_static/metal_debugger/capture.png
+    :class: dark-light
+
+Xcode Workflow
+--------------
+
+You can skip saving to a path by running within Xcode. First, generate an
+Xcode project using CMake.
+
+.. code-block::
+
+    mkdir build && cd build
+    cmake .. -DMLX_METAL_DEBUG=ON -G Xcode
+    open mlx.xcodeproj
+
+Select the ``metal_capture`` example schema and run.
+
+.. image:: ../_static/metal_debugger/schema.png
+    :class: dark-light
+
+.. _`Metal debugger documentation`: https://developer.apple.com/documentation/xcode/metal-debugger

docs/src/examples/llama-inference.rst

@@ -15,7 +15,7 @@ module to concisely define the model architecture.
 Attention layer
 ^^^^^^^^^^^^^^^^
 
-We will start with the llama attention layer which notably uses the RoPE
+We will start with the Llama attention layer which notably uses the RoPE
 positional encoding. [1]_ In addition, our attention layer will optionally use a
 key/value cache that will be concatenated with the provided keys and values to
 support efficient inference.

docs/src/examples/mlp.rst

@@ -64,7 +64,7 @@ set:
 Next, setup the problem parameters and load the data. To load the data, you need our
 `mnist data loader
 <https://github.com/ml-explore/mlx-examples/blob/main/mnist/mnist.py>`_, which
-we will import as `mnist`.
+we will import as ``mnist``.
 
 .. code-block:: python
 

docs/src/index.rst

@@ -41,7 +41,9 @@ are the CPU and GPU.
    usage/indexing
    usage/saving_and_loading
    usage/function_transforms
+   usage/compile
    usage/numpy
+   usage/distributed
    usage/using_streams
 
 .. toctree::
@@ -57,14 +59,18 @@ are the CPU and GPU.
    :maxdepth: 1
 
    python/array
+   python/data_types
    python/devices_and_streams
    python/ops
    python/random
    python/transforms
+   python/fast
    python/fft
    python/linalg
+   python/metal
    python/nn
    python/optimizers
+   python/distributed
    python/tree_utils
 
 .. toctree::
@@ -78,3 +84,5 @@ are the CPU and GPU.
    :maxdepth: 1
 
    dev/extensions
+   dev/metal_debugger
+   dev/custom_metal_kernels

docs/src/install.rst

@@ -15,10 +15,10 @@ To install from PyPI you must meet the following requirements:
 
 - Using an M series chip (Apple silicon)
 - Using a native Python >= 3.8
-- macOS >= 13.3
+- macOS >= 13.5
 
 .. note::
-    MLX is only available on devices running macOS >= 13.3 
+    MLX is only available on devices running macOS >= 13.5
     It is highly recommended to use macOS 14 (Sonoma)
 
 
@@ -54,7 +54,7 @@ Build Requirements
 
 - A C++ compiler with C++17 support (e.g. Clang >= 5.0)
 - `cmake <https://cmake.org/>`_ -- version 3.24 or later, and ``make``
-- Xcode >= 14.3 (Xcode >= 15.0 for macOS 14 and above)
+- Xcode >= 15.0 and macOS SDK >= 14.0
 
 .. note::
    Ensure your shell environment is native ``arm``, not ``x86`` via Rosetta. If
@@ -70,39 +70,36 @@ To build and install the MLX python library from source, first, clone MLX from
 
    git clone git@github.com:ml-explore/mlx.git mlx && cd mlx
 
-Make sure that you have `pybind11 <https://pybind11.readthedocs.io/en/stable/index.html>`_
-installed. You can install ``pybind11`` with ``pip``, ``brew`` or ``conda`` as follows:
+Then simply build and install MLX using pip:
 
 .. code-block:: shell
 
-    pip install "pybind11[global]"
-    conda install pybind11
-    brew install pybind11
+  CMAKE_BUILD_PARALLEL_LEVEL="" pip install .
 
-Then simply build and install it using pip:
+For developing, install the package with development dependencies, and use an
+editable install:
 
 .. code-block:: shell
 
-   env CMAKE_BUILD_PARALLEL_LEVEL="" pip install .
+  CMAKE_BUILD_PARALLEL_LEVEL="" pip install -e ".[dev]"
 
-For developing use an editable install:
+Once the development dependencies are installed, you can build faster with:
 
 .. code-block:: shell
 
-  env CMAKE_BUILD_PARALLEL_LEVEL="" pip install -e .
+ CMAKE_BUILD_PARALLEL_LEVEL="" python setup.py build_ext -j --inplace
 
-To make sure the install is working run the tests with:
+Run the tests with:
 
 .. code-block:: shell
 
-  pip install ".[testing]"
   python -m unittest discover python/tests
 
-Optional: Install stubs to enable auto completions and type checking from your IDE:
+Optional: Install stubs to enable auto completions and type checking from your
+IDE:
 
 .. code-block:: shell
 
-  pip install ".[dev]"
   python setup.py generate_stubs
 
 C++ API
@@ -123,7 +120,7 @@ Create a build directory and run CMake and make:
 .. code-block:: shell
 
    mkdir -p build && cd build
-   cmake .. && make -j 
+   cmake .. && make -j
 
 Run tests with:
 
@@ -142,7 +139,7 @@ directory as the executable statically linked to ``libmlx.a`` or the
 preprocessor constant ``METAL_PATH`` should be defined at build time and it
 should point to the path to the built metal library.
 
-.. list-table:: Build Options 
+.. list-table:: Build Options
    :widths: 25 8
    :header-rows: 1
 
@@ -156,31 +153,67 @@ should point to the path to the built metal library.
      - OFF
    * - MLX_BUILD_METAL
      - ON
+   * - MLX_BUILD_CPU
+     - ON
    * - MLX_BUILD_PYTHON_BINDINGS
      - OFF
-
+   * - MLX_METAL_DEBUG
+     - OFF
+   * - MLX_BUILD_SAFETENSORS
+     - ON
+   * - MLX_BUILD_GGUF
+     - ON
+   * - MLX_METAL_JIT
+     - OFF
 
 .. note::
 
-    If you have multiple Xcode installations and wish to use 
-    a specific one while building, you can do so by adding the 
-    following environment variable before building 
+    If you have multiple Xcode installations and wish to use
+    a specific one while building, you can do so by adding the
+    following environment variable before building
 
     .. code-block:: shell
 
       export DEVELOPER_DIR="/path/to/Xcode.app/Contents/Developer/"
 
-    Further, you can use the following command to find out which 
+    Further, you can use the following command to find out which
     macOS SDK will be used
 
     .. code-block:: shell
 
       xcrun -sdk macosx --show-sdk-version
 
+Binary Size Minimization
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+To produce a smaller binary use the CMake flags ``CMAKE_BUILD_TYPE=MinSizeRel``
+and ``BUILD_SHARED_LIBS=ON``.
+
+The MLX CMake build has several additional options to make smaller binaries.
+For example, if you don't need the CPU backend or support for safetensors and
+GGUF, you can do:
+
+.. code-block:: shell
+
+  cmake .. \
+    -DCMAKE_BUILD_TYPE=MinSizeRel \
+    -DBUILD_SHARED_LIBS=ON \
+    -DMLX_BUILD_CPU=OFF \
+    -DMLX_BUILD_SAFETENSORS=OFF \
+    -DMLX_BUILD_GGUF=OFF \
+    -DMLX_METAL_JIT=ON
+
+THE ``MLX_METAL_JIT`` flag minimizes the size of the MLX Metal library which
+contains pre-built GPU kernels. This substantially reduces the size of the
+Metal library by run-time compiling kernels the first time they are used in MLX
+on a given machine. Note run-time compilation incurs a cold-start cost which can
+be anwywhere from a few hundred millisecond to a few seconds depending on the
+application. Once a kernel is compiled, it will be cached by the system. The
+Metal kernel cache persists accross reboots.
+
 Troubleshooting
 ^^^^^^^^^^^^^^^
 
-
 Metal not found
 ~~~~~~~~~~~~~~~
 
@@ -202,7 +235,7 @@ Then set the active developer directory:
 
   sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer
 
-x86 Shell 
+x86 Shell
 ~~~~~~~~~
 
 .. _build shell:

docs/src/python/array.rst

@@ -10,27 +10,39 @@ Array
 
     array
     array.astype
+    array.at
     array.item
     array.tolist
     array.dtype
+    array.itemsize
+    array.nbytes
     array.ndim
     array.shape
     array.size
-    Dtype
     array.abs
     array.all
     array.any
     array.argmax
     array.argmin
+    array.conj
     array.cos
-    array.dtype
+    array.cummax
+    array.cummin
+    array.cumprod
+    array.cumsum
+    array.diag
+    array.diagonal
     array.exp
+    array.flatten
     array.log
+    array.log10
     array.log1p
+    array.log2
     array.logsumexp
     array.max
     array.mean
     array.min
+    array.moveaxis
     array.prod
     array.reciprocal
     array.reshape
@@ -40,7 +52,10 @@ Array
     array.split
     array.sqrt
     array.square
+    array.squeeze
+    array.swapaxes
     array.sum
     array.transpose
     array.T
     array.var
+    array.view

docs/src/python/data_types.rst

@@ -1,7 +1,5 @@
 .. _data_types:
 
-:orphan:
-
 Data Types
 ==========
 
@@ -44,9 +42,27 @@ The default floating point type is ``float32`` and the default integer type is
    * - ``int64``
      - 8 
      - 64-bit signed integer 
+   * - ``bfloat16``
+     - 2 
+     - 16-bit brain float (e8, m7)
    * - ``float16``
      - 2 
-     - 16-bit float, only available with `ARM C language extensions <https://developer.arm.com/documentation/101028/0012/3--C-language-extensions?lang=en>`_
+     - 16-bit IEEE float (e5, m10)
    * - ``float32``
      - 4 
      - 32-bit float
+   * - ``complex64``
+     - 8 
+     - 64-bit complex float
+
+
+Data type are aranged in a hierarchy. See the :obj:`DtypeCategory` object
+documentation for more information. Use :func:`issubdtype` to determine if one
+``dtype`` (or category) is a subtype of another category.
+
+.. autosummary::
+   :toctree: _autosummary
+
+   Dtype
+   DtypeCategory
+   issubdtype

docs/src/python/devices_and_streams.rst

@@ -9,9 +9,11 @@ Devices and Streams
   :toctree: _autosummary
 
    Device
+   Stream
    default_device
    set_default_device
-   Stream
    default_stream
    new_stream
    set_default_stream
+   stream
+   synchronize

docs/src/python/distributed.rst

@@ -0,0 +1,19 @@
+.. _distributed:
+
+.. currentmodule:: mlx.core.distributed
+
+Distributed Communication
+==========================
+
+MLX provides a distributed communication package using MPI. The MPI library is
+loaded at runtime; if MPI is available then distributed communication is also
+made available.
+
+.. autosummary::
+   :toctree: _autosummary
+
+    Group
+    is_available
+    init
+    all_sum
+    all_gather

docs/src/python/fast.rst

@@ -0,0 +1,16 @@
+.. _fast:
+
+Fast
+====
+
+.. currentmodule:: mlx.core.fast
+
+.. autosummary:: 
+  :toctree: _autosummary
+
+  rms_norm
+  layer_norm
+  rope
+  scaled_dot_product_attention
+  affine_quantize
+  metal_kernel

docs/src/python/linalg.rst

@@ -8,5 +8,10 @@ Linear Algebra
 .. autosummary:: 
    :toctree: _autosummary 
 
+    inv
+    tri_inv
     norm
+    cholesky
+    cholesky_inv
     qr
+    svd

docs/src/python/metal.rst

@@ -0,0 +1,19 @@
+Metal
+=====
+
+.. currentmodule:: mlx.core.metal
+
+.. autosummary::
+  :toctree: _autosummary
+
+  is_available
+  device_info
+  get_active_memory
+  get_peak_memory
+  reset_peak_memory
+  get_cache_memory
+  set_memory_limit
+  set_cache_limit
+  clear_cache
+  start_capture
+  stop_capture

docs/src/python/nn.rst

@@ -173,6 +173,7 @@ In detail:
    :toctree: _autosummary
 
    value_and_grad
+   quantize
 
 .. toctree::
 

docs/src/python/nn/functions.rst

@@ -12,13 +12,27 @@ simple functions.
    :toctree: _autosummary_functions
    :template: nn-module-template.rst
 
+   elu
    gelu
    gelu_approx
    gelu_fast_approx
+   glu
+   hard_shrink
+   hard_tanh
+   hardswish
+   leaky_relu
+   log_sigmoid
+   log_softmax
    mish
    prelu
    relu
+   relu6
    selu
-   softshrink
+   sigmoid
    silu
+   softmax
+   softmin
+   softplus
+   softshrink
    step
+   tanh

docs/src/python/nn/layers.rst

@@ -10,29 +10,50 @@ Layers
    :template: nn-module-template.rst
 
    ALiBi
+   AvgPool1d
+   AvgPool2d
    BatchNorm
    Conv1d
    Conv2d
+   Conv3d
    Dropout
    Dropout2d
    Dropout3d
    Embedding
    GELU
+   GLU
    GroupNorm
+   GRU
+   HardShrink
+   HardTanh
+   Hardswish
    InstanceNorm
    LayerNorm
+   LeakyReLU
    Linear
+   LSTM
+   MaxPool1d
+   MaxPool2d
    Mish
    MultiHeadAttention
    PReLU
+   QuantizedEmbedding
    QuantizedLinear
    RMSNorm
    ReLU
+   ReLU6
+   RNN
    RoPE
    SELU
    Sequential
    SiLU
    SinusoidalPositionalEncoding
+   Softmin
    Softshrink
+   Softsign
+   Softmax
+   Softplus
    Step
+   Tanh
    Transformer
+   Upsample

docs/src/python/nn/losses.rst

@@ -18,6 +18,7 @@ Loss Functions
    kl_div_loss
    l1_loss
    log_cosh_loss
+   margin_ranking_loss
    mse_loss
    nll_loss
    smooth_l1_loss

docs/src/python/nn/module.rst

@@ -11,6 +11,7 @@ Module
       :toctree: _autosummary
    
       Module.training
+      Module.state
    
    .. rubric:: Methods
 
@@ -29,6 +30,7 @@ Module
       Module.named_modules
       Module.parameters
       Module.save_weights
+      Module.set_dtype
       Module.train
       Module.trainable_parameters
       Module.unfreeze

docs/src/python/ops.rst

@@ -5,13 +5,14 @@ Operations
 
 .. currentmodule:: mlx.core
 
-.. autosummary:: 
+.. autosummary::
   :toctree: _autosummary
 
    abs
    add
+   addmm
    all
-   allclose 
+   allclose
    any
    arange
    arccos
@@ -19,44 +20,71 @@ Operations
    arcsin
    arcsinh
    arctan
+   arctan2
    arctanh
    argmax
    argmin
    argpartition
    argsort
    array_equal
+   as_strided
+   atleast_1d
+   atleast_2d
+   atleast_3d
+   bitwise_and
+   bitwise_or
+   bitwise_xor
+   block_masked_mm
    broadcast_to
    ceil
    clip
    concatenate
+   conj
+   conjugate
    convolve
    conv1d
    conv2d
+   conv3d
+   conv_general
    cos
    cosh
+   cummax
+   cummin
+   cumprod
+   cumsum
+   degrees
    dequantize
    diag
    diagonal
    divide
    divmod
+   einsum
+   einsum_path
    equal
    erf
    erfinv
    exp
+   expm1
    expand_dims
    eye
    flatten
    floor
    floor_divide
    full
+   gather_mm
+   gather_qmm
    greater
    greater_equal
+   hadamard_transform
    identity
    inner
-   isnan
-   isposinf
-   isneginf
+   isclose
    isinf
+   isnan
+   isneginf
+   isposinf
+   issubdtype
+   left_shift
    less
    less_equal
    linspace
@@ -74,22 +102,29 @@ Operations
    max
    maximum
    mean
+   meshgrid
    min
    minimum
    moveaxis
    multiply
+   nan_to_num
    negative
+   not_equal
    ones
    ones_like
    outer
    partition
    pad
+   power
    prod
    quantize
    quantized_matmul
+   radians
    reciprocal
+   remainder
    repeat
    reshape
+   right_shift
    round
    rsqrt
    save
@@ -108,6 +143,7 @@ Operations
    square
    squeeze
    stack
+   std
    stop_gradient
    subtract
    sum
@@ -117,11 +153,15 @@ Operations
    tan
    tanh
    tensordot
+   tile
+   topk
+   trace
    transpose
    tri
    tril
    triu
    var
+   view
    where
    zeros
    zeros_like

docs/src/python/optimizers.rst

@@ -1,5 +1,7 @@
 .. _optimizers:
 
+.. currentmodule:: mlx.optimizers
+
 Optimizers
 ==========
 
@@ -29,20 +31,48 @@ model's parameters and the **optimizer state**.
             # Compute the new parameters but also the optimizer state.
             mx.eval(model.parameters(), optimizer.state)
 
-.. currentmodule:: mlx.optimizers
+Saving and Loading
+------------------
+
+To serialize an optimizer, save its state. To load an optimizer, load and set
+the saved state. Here's a simple example:
+
+.. code-block:: python
+
+   import mlx.core as mx
+   from mlx.utils import tree_flatten, tree_unflatten
+   import mlx.optimizers as optim
+
+   optimizer = optim.Adam(learning_rate=1e-2)
+
+   # Perform some updates with the optimizer
+   model = {"w" : mx.zeros((5, 5))}
+   grads = {"w" : mx.ones((5, 5))}
+   optimizer.update(model, grads)
+
+   # Save the state
+   state = tree_flatten(optimizer.state)
+   mx.save_safetensors("optimizer.safetensors", dict(state))
+
+   # Later on, for example when loading from a checkpoint,
+   # recreate the optimizer and load the state
+   optimizer = optim.Adam(learning_rate=1e-2)
+
+   state = tree_unflatten(list(mx.load("optimizer.safetensors").items()))
+   optimizer.state = state
+
+Note, not every optimizer configuation parameter is saved in the state. For
+example, for Adam the learning rate is saved but the ``betas`` and ``eps``
+parameters are not. A good rule of thumb is if the parameter can be scheduled
+then it will be included in the optimizer state.
+
+.. toctree::
+
+   optimizers/optimizer
+   optimizers/common_optimizers
+   optimizers/schedulers
 
 .. autosummary::
    :toctree: _autosummary
-   :template: optimizers-template.rst
 
-   OptimizerState
-   Optimizer
-   SGD
-   RMSprop
-   Adagrad
-   Adafactor
-   AdaDelta
-   Adam
-   AdamW
-   Adamax
-   Lion
+   clip_grad_norm

docs/src/python/optimizers/common_optimizers.rst

@@ -0,0 +1,20 @@
+.. _common_optimizers:
+
+Common Optimizers
+=================
+
+.. currentmodule:: mlx.optimizers
+
+.. autosummary::
+   :toctree: _autosummary
+   :template: optimizers-template.rst
+
+   SGD
+   RMSprop
+   Adagrad
+   Adafactor
+   AdaDelta
+   Adam
+   AdamW
+   Adamax
+   Lion

docs/src/python/optimizers/optimizer.rst

@@ -0,0 +1,23 @@
+Optimizer
+=========
+
+.. currentmodule:: mlx.optimizers
+
+.. autoclass:: Optimizer 
+
+
+   .. rubric:: Attributes
+
+   .. autosummary::
+      :toctree: _autosummary
+
+      Optimizer.state
+   
+   .. rubric:: Methods
+
+   .. autosummary::
+      :toctree: _autosummary
+   
+      Optimizer.apply_gradients
+      Optimizer.init
+      Optimizer.update

docs/src/python/optimizers/schedulers.rst

@@ -0,0 +1,15 @@
+.. _schedulers:
+
+Schedulers
+==========
+
+.. currentmodule:: mlx.optimizers
+
+.. autosummary::
+   :toctree: _autosummary
+
+   cosine_decay    
+   exponential_decay    
+   join_schedules
+   linear_schedule
+   step_decay    

docs/src/python/random.rst

@@ -38,8 +38,10 @@ we use a splittable version of Threefry, which is a counter-based PRNG.
    gumbel
    key
    normal
+   multivariate_normal
    randint
    seed
    split
    truncated_normal
    uniform
+   laplace

docs/src/python/transforms.rst

@@ -9,6 +9,10 @@ Transforms
   :toctree: _autosummary
 
    eval
+   compile
+   custom_function
+   disable_compile
+   enable_compile
    grad
    value_and_grad
    jvp

docs/src/python/tree_utils.rst

@@ -19,3 +19,5 @@ return python trees will be using the default python ``dict``, ``list`` and
    tree_flatten
    tree_unflatten
    tree_map
+   tree_map_with_path
+   tree_reduce

docs/src/usage/compile.rst

@@ -0,0 +1,430 @@
+.. _compile:
+
+Compilation
+===========
+
+.. currentmodule:: mlx.core
+
+MLX has a :func:`compile` function transformation which compiles computation
+graphs. Function compilation results in smaller graphs by merging common work
+and fusing certain operations. In many cases this can lead to big improvements
+in run-time and memory use.
+
+Getting started with :func:`compile` is simple, but there are some edge cases
+that are good to be aware of for more complex graphs and advanced usage.
+
+Basics of Compile
+-----------------
+
+Let's start with a simple example:
+
+.. code-block:: python
+
+  def fun(x, y):
+      return mx.exp(-x) + y
+
+  x = mx.array(1.0)
+  y = mx.array(2.0)
+
+  # Regular call, no compilation
+  # Prints: array(2.36788, dtype=float32)
+  print(fun(x, y))
+
+  # Compile the function
+  compiled_fun = mx.compile(fun)
+
+  # Prints: array(2.36788, dtype=float32) 
+  print(compiled_fun(x, y))
+
+The output of both the regular function and the compiled function is the same
+up to numerical precision.
+   
+The first time you call a compiled function, MLX will build the compute
+graph, optimize it, and generate and compile code. This can be relatively
+slow. However, MLX will cache compiled functions, so calling a compiled
+function multiple times will not initiate a new compilation. This means you
+should typically compile functions that you plan to use more than once.
+
+.. code-block:: python
+
+  def fun(x, y):
+      return mx.exp(-x) + y
+
+  x = mx.array(1.0)
+  y = mx.array(2.0)
+
+  compiled_fun = mx.compile(fun)
+
+  # Compiled here
+  compiled_fun(x, y)
+
+  # Not compiled again
+  compiled_fun(x, y)
+
+  # Not compiled again
+  mx.compile(fun)(x, y)
+
+There are some important cases to be aware of that can cause a function to
+be recompiled:
+
+* Changing the shape or number of dimensions
+* Changing the type of any of the inputs
+* Changing the number of inputs to the function
+
+In certain cases only some of the compilation stack will be rerun (for
+example when changing the shapes) and in other cases the full compilation
+stack will be rerun (for example when changing the types). In general you
+should avoid compiling functions too frequently.
+
+Another idiom to watch out for is compiling functions which get created and
+destroyed frequently. This can happen, for example, when compiling an anonymous
+function in a loop:
+
+.. code-block:: python
+
+  a = mx.array(1.0)
+  # Don't do this, compiles lambda at each iteration
+  for _ in range(5):
+      mx.compile(lambda x: mx.exp(mx.abs(x)))(a)
+
+Example Speedup
+---------------
+
+The :func:`mlx.nn.gelu` is a nonlinear activation function commonly used with
+Transformer-based models. The implementation involves several unary and binary
+element-wise operations:
+
+.. code-block:: python
+
+  def gelu(x):  
+      return x * (1 + mx.erf(x / math.sqrt(2))) / 2
+
+If you use this function with small arrays, it will be overhead bound. If you
+use it with large arrays it will be memory bandwidth bound.  However, all of
+the operations in the ``gelu`` are fusible into a single kernel with
+:func:`compile`. This can speedup both cases considerably.
+
+Let's compare the runtime of the regular function versus the compiled
+function. We'll use the following timing helper which does a warm up and
+handles synchronization:
+
+.. code-block:: python
+
+  import time
+
+  def timeit(fun, x):
+      # warm up
+      for _ in range(10):
+          mx.eval(fun(x))
+
+      tic = time.perf_counter()
+      for _ in range(100):
+          mx.eval(fun(x))
+      toc = time.perf_counter()
+      tpi = 1e3 * (toc - tic) / 100
+      print(f"Time per iteration {tpi:.3f} (ms)")
+
+
+Now make an array, and benchmark both functions:
+
+.. code-block:: python
+
+  x = mx.random.uniform(shape=(32, 1000, 4096))
+  timeit(nn.gelu, x)
+  timeit(mx.compile(nn.gelu), x)
+
+On an M1 Max the times are 15.5 and 3.1 milliseconds. The compiled ``gelu`` is
+five times faster.
+
+.. note::
+
+  As of the latest MLX, CPU functions are not fully compiled. Compiling CPU
+  functions can still be helpful, but won't typically result in as large a
+  speedup as compiling operations that run on the GPU.
+
+
+Debugging
+---------
+
+When a compiled function is first called, it is traced with placeholder
+inputs. This means you can't evaluate arrays (for example to print their
+contents) inside compiled functions.
+
+.. code-block:: python
+
+  @mx.compile
+  def fun(x):
+      z = -x
+      print(z)  # Crash
+      return mx.exp(z)
+
+  fun(mx.array(5.0))
+
+For debugging, inspecting arrays can be helpful. One way to do that is to
+globally disable compilation using the :func:`disable_compile` function or
+``MLX_DISABLE_COMPILE`` flag. For example the following is okay even though
+``fun`` is compiled:
+
+.. code-block:: python
+
+  @mx.compile
+  def fun(x):
+      z = -x
+      print(z) # Okay
+      return mx.exp(z)
+
+  mx.disable_compile()
+  fun(mx.array(5.0))
+
+
+Pure Functions
+--------------
+
+Compiled functions are intended to be *pure*; that is they should not have side
+effects. For example:
+
+.. code-block:: python
+
+  state = []
+
+  @mx.compile
+  def fun(x, y):
+      z = x + y
+      state.append(z)
+      return mx.exp(z)
+
+  fun(mx.array(1.0), mx.array(2.0))
+  # Crash!
+  print(state)
+
+After the first call of ``fun``, the ``state`` list will hold a placeholder
+array. The placeholder does not have any data; it is only used to build the
+computation graph. Printing such an array results in a crash.
+
+You have two options to deal with this. The first option is to simply return
+``state`` as an output:
+
+.. code-block:: python
+
+   state = []
+
+   @mx.compile
+   def fun(x, y):
+      z = x + y
+      state.append(z)
+      return mx.exp(z), state
+
+    _, state = fun(mx.array(1.0), mx.array(2.0))
+    # Prints [array(3, dtype=float32)]
+    print(state)
+
+In some cases returning updated state can be pretty inconvenient. Hence,
+:func:`compile` has a parameter to capture implicit outputs:
+
+.. code-block:: python
+
+  from functools import partial
+
+  state = []
+
+  # Tell compile to capture state as an output
+  @partial(mx.compile, outputs=state)
+  def fun(x, y):
+      z = x + y
+      state.append(z)
+      return mx.exp(z), state
+
+  fun(mx.array(1.0), mx.array(2.0))
+  # Prints [array(3, dtype=float32)]
+  print(state)
+
+This is particularly useful for compiling a function which includes an update
+to a container of arrays, as is commonly done when training the parameters of a
+:class:`mlx.nn.Module`.
+
+Compiled functions will also treat any inputs not in the parameter list as
+constants. For example:
+
+.. code-block:: python
+
+  state = [mx.array(1.0)]
+
+  @mx.compile
+  def fun(x):
+      return x + state[0]
+
+  # Prints array(2, dtype=float32)
+  print(fun(mx.array(1.0)))
+
+  # Update state
+  state[0] = mx.array(5.0)
+
+  # Still prints array(2, dtype=float32)
+  print(fun(mx.array(1.0)))
+
+In order to have the change of state reflected in the outputs of ``fun`` you
+again have two options. The first option is to simply pass ``state`` as input
+to the function. In some cases this can be pretty inconvenient. Hence,
+:func:`compile` also has a parameter to capture implicit inputs:
+
+.. code-block:: python
+
+  from functools import partial
+  state = [mx.array(1.0)]
+
+  # Tell compile to capture state as an input
+  @partial(mx.compile, inputs=state)
+  def fun(x):
+      return x + state[0]
+
+  # Prints array(2, dtype=float32)
+  print(fun(mx.array(1.0)))
+
+  # Update state
+  state[0] = mx.array(5.0)
+
+  # Prints array(6, dtype=float32)
+  print(fun(mx.array(1.0)))
+
+
+Compiling Training Graphs 
+-------------------------
+
+This section will step through how to use :func:`compile` with a simple example
+of a common setup: training a model with :obj:`mlx.nn.Module` using an
+:obj:`mlx.optimizers.Optimizer` with state. We will show how to compile the
+full forward, backward, and update with :func:`compile`.
+
+To start, here is the simple example without any compilation:
+
+.. code-block:: python 
+
+  import mlx.core as mx
+  import mlx.nn as nn
+  import mlx.optimizers as optim
+
+  # 4 examples with 10 features each
+  x = mx.random.uniform(shape=(4, 10))
+
+  # 0, 1 targets
+  y = mx.array([0, 1, 0, 1])
+
+  # Simple linear model
+  model = nn.Linear(10, 1)
+
+  # SGD with momentum
+  optimizer = optim.SGD(learning_rate=0.1, momentum=0.8)
+
+  def loss_fn(model, x, y):
+      logits = model(x).squeeze()
+      return nn.losses.binary_cross_entropy(logits, y)
+
+  loss_and_grad_fn = nn.value_and_grad(model, loss_fn)
+
+  # Perform 10 steps of gradient descent
+  for it in range(10):
+      loss, grads = loss_and_grad_fn(model, x, y)
+      optimizer.update(model, grads)
+      mx.eval(model.parameters(), optimizer.state)
+
+To compile the update we can put it all in a function and compile it with the
+appropriate input and output captures. Here's the same example but compiled:
+
+.. code-block:: python 
+
+  import mlx.core as mx
+  import mlx.nn as nn
+  import mlx.optimizers as optim
+  from functools import partial
+
+  # 4 examples with 10 features each
+  x = mx.random.uniform(shape=(4, 10))
+
+  # 0, 1 targets
+  y = mx.array([0, 1, 0, 1])
+
+  # Simple linear model
+  model = nn.Linear(10, 1)
+
+  # SGD with momentum
+  optimizer = optim.SGD(learning_rate=0.1, momentum=0.8)
+
+  def loss_fn(model, x, y):
+      logits = model(x).squeeze()
+      return nn.losses.binary_cross_entropy(logits, y)
+
+  # The state that will be captured as input and output
+  state = [model.state, optimizer.state]
+      
+  @partial(mx.compile, inputs=state, outputs=state)
+  def step(x, y):
+      loss_and_grad_fn = nn.value_and_grad(model, loss_fn)
+      loss, grads = loss_and_grad_fn(model, x, y)
+      optimizer.update(model, grads)
+      return loss
+
+  # Perform 10 steps of gradient descent
+  for it in range(10):
+      loss = step(x, y)
+      # Evaluate the model and optimizer state
+      mx.eval(state)
+      print(loss)
+
+
+.. note::
+
+  If you are using a module which performs random sampling such as
+  :func:`mlx.nn.Dropout`, make sure you also include ``mx.random.state`` in the
+  ``state`` captured by :func:`compile`, i.e. ``state = [model.state,
+  optimizer.state, mx.random.state]``.
+
+
+.. note::
+
+   For more examples of compiling full training graphs checkout the  `MLX
+   Examples <https://github.com/ml-explore/mlx-examples>`_ GitHub repo.
+
+Transformations with Compile
+----------------------------
+
+In MLX function transformations are composable. You can apply any function
+transformation to the output of any other function transformation. For more on
+this, see the documentation on :ref:`function transforms
+<function_transforms>`.
+
+Compiling transformed functions works just as expected:
+
+.. code-block:: python
+
+  grad_fn = mx.grad(mx.exp)
+
+  compiled_grad_fn = mx.compile(grad_fn)
+
+  # Prints: array(2.71828, dtype=float32)
+  print(grad_fn(mx.array(1.0)))
+
+  # Also prints: array(2.71828, dtype=float32)
+  print(compiled_grad_fn(mx.array(1.0)))
+
+.. note::
+
+   In order to compile as much as possible, a transformation of a compiled
+   function will not by default be compiled. To compile the transformed
+   function simply pass it through :func:`compile`. 
+
+You can also compile functions which themselves call compiled functions. A
+good practice is to compile the outer most function to give :func:`compile`
+the most opportunity to optimize the computation graph:
+
+.. code-block:: python
+
+  @mx.compile
+  def inner(x):
+      return mx.exp(-mx.abs(x))
+
+  def outer(x):
+      inner(inner(x))
+
+  # Compiling the outer function is good to do as it will likely
+  # be faster even though the inner functions are compiled
+  fun = mx.compile(outer)

docs/src/usage/distributed.rst

@@ -0,0 +1,166 @@
+.. _usage_distributed:
+
+Distributed Communication
+=========================
+
+.. currentmodule:: mlx.core.distributed
+
+MLX utilizes `MPI <https://en.wikipedia.org/wiki/Message_Passing_Interface>`_ to
+provide distributed communication operations that allow the computational cost
+of training or inference to be shared across many physical machines. You can
+see a list of the supported operations in the :ref:`API docs<distributed>`.
+
+.. note::
+   A lot of operations may not be supported or not as fast as they should be.
+   We are adding more and tuning the ones we have as we are figuring out the
+   best way to do distributed computing on Macs using MLX.
+
+Getting Started
+---------------
+
+MLX already comes with the ability to "talk" to MPI if it is installed on the
+machine. The minimal distributed program in MLX is as simple as:
+
+.. code:: python
+
+    import mlx.core as mx
+
+    world = mx.distributed.init()
+    x = mx.distributed.all_sum(mx.ones(10))
+    print(world.rank(), x)
+
+The program above sums the array ``mx.ones(10)`` across all
+distributed processes. If simply run with ``python``, however, only one
+process is launched and no distributed communication takes place.
+
+To launch the program in distributed mode we need to use ``mpirun`` or
+``mpiexec`` depending on the MPI installation. The simplest possible way is the
+following:
+
+.. code:: shell
+
+    $ mpirun -np 2 python test.py
+    1 array([2, 2, 2, ..., 2, 2, 2], dtype=float32)
+    0 array([2, 2, 2, ..., 2, 2, 2], dtype=float32)
+
+The above launches two processes on the same (local) machine and we can see
+both standard output streams. The processes send the array of 1s to each other
+and compute the sum which is printed. Launching with ``mpirun -np 4 ...`` would
+print 4 etc.
+
+Installing MPI
+---------------
+
+MPI can be installed with Homebrew, using the Anaconda package manager or
+compiled from source. Most of our testing is done using ``openmpi`` installed
+with the Anaconda package manager as follows:
+
+.. code:: shell
+
+    $ conda install openmpi
+
+Installing with Homebrew may require specifying the location of ``libmpi.dyld``
+so that MLX can find it and load it at runtime. This can simply be achieved by
+passing the ``DYLD_LIBRARY_PATH`` environment variable to ``mpirun``.
+
+.. code:: shell
+
+    $ mpirun -np 2 -x DYLD_LIBRARY_PATH=/opt/homebrew/lib/ python test.py
+
+Setting up Remote Hosts
+-----------------------
+
+MPI can automatically connect to remote hosts and set up the communication over
+the network if the remote hosts can be accessed via ssh. A good checklist to
+debug connectivity issues is the following:
+
+* ``ssh hostname`` works from all machines to all machines without asking for
+  password or host confirmation
+* ``mpirun`` is accessible on all machines. You can call ``mpirun`` using its
+  full path to force all machines to use a specific path.
+* Ensure that the ``hostname`` used by MPI is the one that you have configured
+  in the ``.ssh/config`` files on all machines.
+
+.. note::
+  For an example hostname ``foo.bar.com`` MPI can use only ``foo`` as
+  the hostname passed to ssh if the current hostname matches ``*.bar.com``.
+
+An easy way to pass the host names to MPI is using a host file. A host file
+looks like the following, where ``host1`` and ``host2`` should be the fully
+qualified domain names or IPs for these hosts.
+
+.. code::
+
+    host1 slots=1
+    host2 slots=1
+
+When using MLX, it is very likely that you want to use 1 slot per host, ie one
+process per host.  The hostfile also needs to contain the current
+host if you want to run on the local host. Passing the host file to
+``mpirun`` is simply done using the ``--hostfile`` command line argument.
+
+Training Example
+----------------
+
+In this section we will adapt an MLX training loop to support data parallel
+distributed training. Namely, we will average the gradients across a set of
+hosts before applying them to the model.
+
+Our training loop looks like the following code snippet if we omit the model,
+dataset and optimizer initialization.
+
+.. code:: python
+
+    model = ...
+    optimizer = ...
+    dataset = ...
+
+    def step(model, x, y):
+        loss, grads = loss_grad_fn(model, x, y)
+        optimizer.update(model, grads)
+        return loss
+
+    for x, y in dataset:
+        loss = step(model, x, y)
+        mx.eval(loss, model.parameters())
+
+All we have to do to average the gradients across machines is perform an
+:func:`all_sum` and divide by the size of the :class:`Group`. Namely we
+have to :func:`mlx.utils.tree_map` the gradients with following function.
+
+.. code:: python
+
+    def all_avg(x):
+        return mx.distributed.all_sum(x) / mx.distributed.init().size()
+
+Putting everything together our training loop step looks as follows with
+everything else remaining the same.
+
+.. code:: python
+
+    from mlx.utils import tree_map
+
+    def all_reduce_grads(grads):
+        N = mx.distributed.init()
+        if N == 1:
+            return grads
+        return tree_map(
+                lambda x: mx.distributed.all_sum(x) / N,
+                grads)
+
+    def step(model, x, y):
+        loss, grads = loss_grad_fn(model, x, y)
+        grads = all_reduce_grads(grads)  # <--- This line was added
+        optimizer.update(model, grads)
+        return loss
+
+Tuning All Reduce
+-----------------
+
+We are working on improving the performance of all reduce on MLX but for now
+the two main things one can do to extract the most out of distributed training with MLX are:
+
+1. Perform a few large reductions instead of many small ones to improve
+   bandwidth and latency
+2. Pass ``--mca btl_tcp_links 4`` to ``mpirun`` to configure it to use 4 tcp
+   connections between each host to improve bandwidth

docs/src/usage/function_transforms.rst

@@ -5,9 +5,12 @@ Function Transforms
 
 .. currentmodule:: mlx.core
 
-MLX uses composable function transformations for automatic differentiation and
-vectorization. The key idea behind composable function transformations is that
-every transformation returns a function which can be further transformed. 
+MLX uses composable function transformations for automatic differentiation,
+vectorization, and compute graph optimizations. To see the complete list of
+function transformations check-out the :ref:`API documentation <transforms>`.
+
+The key idea behind composable function transformations is that every
+transformation returns a function which can be further transformed.
 
 Here is a simple example:
 
@@ -36,10 +39,10 @@ Using :func:`grad` on the output of :func:`grad` is always ok. You keep
 getting higher order derivatives.
 
 Any of the MLX function transformations can be composed in any order to any
-depth. To see the complete list of function transformations check-out the
-:ref:`API documentation <transforms>`. See the following sections for more
-information on :ref:`automatic differentiaion <auto diff>` and
-:ref:`automatic vectorization <vmap>`.
+depth. See the following sections for more information on :ref:`automatic
+differentiation <auto diff>` and :ref:`automatic vectorization <vmap>`.
+For more information on :func:`compile` see the :ref:`compile documentation <compile>`.
+
 
 Automatic Differentiation
 -------------------------

docs/src/usage/lazy_evaluation.rst

@@ -18,7 +18,7 @@ describe below.
 Transforming Compute Graphs
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Lazy evaluation let's us record a compute graph without actually doing any
+Lazy evaluation lets us record a compute graph without actually doing any
 computations. This is useful for function transformations like :func:`grad` and
 :func:`vmap` and graph optimizations.
 

docs/src/usage/numpy.rst

@@ -3,7 +3,11 @@
 Conversion to NumPy and Other Frameworks
 ========================================
 
-MLX array implements the `Python Buffer Protocol <https://docs.python.org/3/c-api/buffer.html>`_.
+MLX array supports conversion between other frameworks with either:  
+
+* The `Python Buffer Protocol <https://docs.python.org/3/c-api/buffer.html>`_. 
+* `DLPack <https://dmlc.github.io/dlpack/latest/>`_.  
+
 Let's convert an array to NumPy and back.
 
 .. code-block:: python

docs/src/usage/saving_and_loading.rst

@@ -49,7 +49,7 @@ it will be added. You can load the array with:
 
 .. code-block:: shell
 
-   >>> mx.load("array.npy", a)
+   >>> mx.load("array.npy")
    array([1], dtype=float32)
 
 Here's an example of saving several arrays to a single file:

examples/cpp/CMakeLists.txt

@@ -8,3 +8,5 @@ endfunction(build_example)
 build_example(tutorial.cpp)
 build_example(linear_regression.cpp)
 build_example(logistic_regression.cpp)
+build_example(metal_capture.cpp)
+build_example(distributed.cpp)

examples/cpp/distributed.cpp

@@ -0,0 +1,22 @@
+// Copyright © 2024 Apple Inc.
+
+#include <iostream>
+
+#include "mlx/mlx.h"
+
+using namespace mlx::core;
+
+int main() {
+  if (!distributed::is_available()) {
+    std::cout << "No communication backend found" << std::endl;
+    return 1;
+  }
+
+  auto global_group = distributed::init();
+  std::cout << global_group.rank() << " / " << global_group.size() << std::endl;
+
+  array x = ones({10});
+  array out = distributed::all_sum(x, global_group);
+
+  std::cout << out << std::endl;
+}

examples/cpp/metal_capture.cpp

@@ -0,0 +1,31 @@
+// Copyright © 2024 Apple Inc.
+
+#include <cassert>
+#include <iostream>
+
+#include "mlx/mlx.h"
+
+using namespace mlx::core;
+
+int main() {
+  // To use Metal debugging and profiling:
+  // 1. Build with the MLX_METAL_DEBUG CMake option (i.e. -DMLX_METAL_DEBUG=ON).
+  // 2. Run with MTL_CAPTURE_ENABLED=1.
+  metal::start_capture("mlx_trace.gputrace");
+
+  // Start at index two because the default GPU and CPU streams have indices
+  // zero and one, respectively. This naming matches the label assigned to each
+  // stream's command queue.
+  auto s2 = new_stream(Device::gpu);
+  auto s3 = new_stream(Device::gpu);
+
+  auto a = arange(1.f, 10.f, 1.f, float32, s2);
+  auto b = arange(1.f, 10.f, 1.f, float32, s3);
+  auto x = add(a, a, s2);
+  auto y = add(b, b, s3);
+
+  // The multiply will happen on the default stream.
+  std::cout << multiply(x, y) << std::endl;
+
+  metal::stop_capture();
+}

examples/cpp/tutorial.cpp

@@ -89,8 +89,8 @@ void automatic_differentiation() {
   // dfdx is 2 * x
 
   // Get the second derivative by composing grad with grad
-  auto df2dx2 = grad(grad(fn))(x);
-  // df2dx2 is 2
+  auto d2fdx2 = grad(grad(fn))(x);
+  // d2fdx2 is 2
 }
 
 int main() {

examples/extensions/CMakeLists.txt

@@ -1,6 +1,6 @@
-cmake_minimum_required(VERSION 3.24)
+cmake_minimum_required(VERSION 3.27)
 
-project(mlx_sample_extensions LANGUAGES CXX)
+project(_ext LANGUAGES CXX)
 
 # ----------------------------- Setup -----------------------------
 set(CMAKE_CXX_STANDARD 17)
@@ -11,8 +11,12 @@ option(BUILD_SHARED_LIBS "Build extensions as a shared library" ON)
 
 # ----------------------------- Dependencies -----------------------------
 find_package(MLX CONFIG REQUIRED)
-find_package(Python COMPONENTS Interpreter Development)
-find_package(pybind11 CONFIG REQUIRED)
+find_package(Python 3.8 COMPONENTS Interpreter Development.Module REQUIRED)
+execute_process(
+  COMMAND "${Python_EXECUTABLE}" -m nanobind --cmake_dir
+  OUTPUT_STRIP_TRAILING_WHITESPACE OUTPUT_VARIABLE NB_DIR)
+list(APPEND CMAKE_PREFIX_PATH "${NB_DIR}")
+find_package(nanobind CONFIG REQUIRED)
 
 # ----------------------------- Extensions -----------------------------
 
@@ -38,7 +42,6 @@ target_link_libraries(mlx_ext PUBLIC mlx)
 
 # Build metallib
 if(MLX_BUILD_METAL)
-
   mlx_build_metallib(
     TARGET mlx_ext_metallib
     TITLE mlx_ext
@@ -54,13 +57,15 @@ if(MLX_BUILD_METAL)
 
 endif()
 
-# ----------------------------- Pybind -----------------------------
-pybind11_add_module(
-  mlx_sample_extensions
+# ----------------------------- Python Bindings -----------------------------
+nanobind_add_module(
+  _ext
+  NB_STATIC STABLE_ABI LTO NOMINSIZE
+  NB_DOMAIN mlx 
   ${CMAKE_CURRENT_LIST_DIR}/bindings.cpp
 )
-target_link_libraries(mlx_sample_extensions PRIVATE mlx_ext)
+target_link_libraries(_ext PRIVATE mlx_ext)
 
 if(BUILD_SHARED_LIBS)
-  target_link_options(mlx_sample_extensions PRIVATE -Wl,-rpath,@loader_path)
-endif()
+  target_link_options(_ext PRIVATE -Wl,-rpath,@loader_path)
+endif()

examples/extensions/README.md

@@ -0,0 +1,24 @@
+
+## Build
+
+```
+pip install -e .
+```
+
+For faster builds during development, you can also pre-install the requirements:
+
+```
+pip install -r requirements.txt
+```
+
+And then run:
+
+```
+python setup.py build_ext -j8 --inplace
+```
+
+## Test
+
+```
+python test.py
+```

examples/extensions/axpby/axpby.cpp

@@ -1,4 +1,4 @@
-// Copyright © 2023 Apple Inc.
+// Copyright © 2023-2024 Apple Inc.
 
 #include <cassert>
 #include <iostream>
@@ -43,7 +43,7 @@ array axpby(
   auto promoted_dtype = promote_types(x.dtype(), y.dtype());
 
   // Upcast to float32 for non-floating point inputs x and y
-  auto out_dtype = is_floating_point(promoted_dtype)
+  auto out_dtype = issubdtype(promoted_dtype, float32)
       ? promoted_dtype
       : promote_types(promoted_dtype, float32);
 
@@ -61,7 +61,7 @@ array axpby(
       /* const std::vector<int>& shape = */ out_shape,
       /* Dtype dtype = */ out_dtype,
       /* std::unique_ptr<Primitive> primitive = */
-      std::make_unique<Axpby>(to_stream(s), alpha, beta),
+      std::make_shared<Axpby>(to_stream(s), alpha, beta),
       /* const std::vector<array>& inputs = */ broadcasted_inputs);
 }
 
@@ -106,12 +106,12 @@ void axpby_impl(
 /** Fall back implementation for evaluation on CPU */
 void Axpby::eval(
     const std::vector<array>& inputs,
-    std::vector<array>& out_arr) {
-  auto out = out_arr[0];
+    std::vector<array>& outputs) {
   // Check the inputs (registered in the op while constructing the out array)
   assert(inputs.size() == 2);
   auto& x = inputs[0];
   auto& y = inputs[1];
+  auto& out = outputs[0];
 
   // Dispatch to the correct dtype
   if (out.dtype() == float32) {
@@ -150,11 +150,7 @@ void axpby_impl_accelerate(
   // The data in the output array is allocated to match the strides in y
   // such that x, y, and out are contiguous in the same mode and
   // no transposition is needed
-  out.set_data(
-      allocator::malloc_or_wait(y.data_size() * out.itemsize()),
-      y.data_size(),
-      y.strides(),
-      y.flags());
+  out.set_data(allocator::malloc_or_wait(out.nbytes()));
 
   // We then copy over the elements using the contiguous vector specialization
   copy_inplace(y, out, CopyType::Vector);
@@ -180,11 +176,11 @@ void axpby_impl_accelerate(
 /** Evaluate primitive on CPU using accelerate specializations */
 void Axpby::eval_cpu(
     const std::vector<array>& inputs,
-    std::vector<array>& outarr) {
-  auto out = outarr[0];
+    std::vector<array>& outputs) {
   assert(inputs.size() == 2);
   auto& x = inputs[0];
   auto& y = inputs[1];
+  auto& out = outputs[0];
 
   // Accelerate specialization for contiguous single precision float arrays
   if (out.dtype() == float32 &&
@@ -195,7 +191,7 @@ void Axpby::eval_cpu(
   }
 
   // Fall back to common backend if specializations are not available
-  eval(inputs, outarr);
+  eval(inputs, outputs);
 }
 
 #else // Accelerate not available
@@ -203,8 +199,8 @@ void Axpby::eval_cpu(
 /** Evaluate primitive on CPU falling back to common backend */
 void Axpby::eval_cpu(
     const std::vector<array>& inputs,
-    std::vector<array>& out) {
-  eval(inputs, out);
+    const std::vector<array>& outputs) {
+  eval(inputs, outputs);
 }
 
 #endif
@@ -218,12 +214,12 @@ void Axpby::eval_cpu(
 /** Evaluate primitive on GPU */
 void Axpby::eval_gpu(
     const std::vector<array>& inputs,
-    std::vector<array>& outarr) {
+    std::vector<array>& outputs) {
   // Prepare inputs
-  auto out = outarr[0];
   assert(inputs.size() == 2);
   auto& x = inputs[0];
   auto& y = inputs[1];
+  auto& out = outputs[0];
 
   // Each primitive carries the stream it should execute on
   // and each stream carries its device identifiers
@@ -253,15 +249,14 @@ void Axpby::eval_gpu(
   kname << (contiguous_kernel ? "contiguous_" : "general_");
   kname << type_to_name(out);
 
-  // Make sure the metal library is available and look for it
-  // in the same folder as this executable if needed
-  d.register_library("mlx_ext", metal::get_colocated_mtllib_path);
+  // Make sure the metal library is available
+  d.register_library("mlx_ext");
 
   // Make a kernel from this metal library
   auto kernel = d.get_kernel(kname.str(), "mlx_ext");
 
   // Prepare to encode kernel
-  auto compute_encoder = d.get_command_encoder(s.index);
+  auto& compute_encoder = d.get_command_encoder(s.index);
   compute_encoder->setComputePipelineState(kernel);
 
   // Kernel parameters are registered with buffer indices corresponding to
@@ -270,11 +265,11 @@ void Axpby::eval_gpu(
   size_t nelem = out.size();
 
   // Encode input arrays to kernel
-  set_array_buffer(compute_encoder, x, 0);
-  set_array_buffer(compute_encoder, y, 1);
+  compute_encoder.set_input_array(x, 0);
+  compute_encoder.set_input_array(y, 1);
 
   // Encode output arrays to kernel
-  set_array_buffer(compute_encoder, out, 2);
+  compute_encoder.set_output_array(out, 2);
 
   // Encode alpha and beta
   compute_encoder->setBytes(&alpha_, sizeof(float), 3);
@@ -300,7 +295,7 @@ void Axpby::eval_gpu(
 
   // Launch the grid with the given number of threads divided among
   // the given threadgroups
-  compute_encoder->dispatchThreads(grid_dims, group_dims);
+  compute_encoder.dispatchThreads(grid_dims, group_dims);
 }
 
 #else // Metal is not available
@@ -372,4 +367,4 @@ bool Axpby::is_equivalent(const Primitive& other) const {
   return alpha_ == r_other.alpha_ && beta_ == r_other.beta_;
 }
 
-} // namespace mlx::core
+} // namespace mlx::core

examples/extensions/axpby/axpby.h

@@ -33,7 +33,7 @@ array axpby(
 class Axpby : public Primitive {
  public:
   explicit Axpby(Stream stream, float alpha, float beta)
-      : Primitive(stream), alpha_(alpha), beta_(beta){};
+      : Primitive(stream), alpha_(alpha), beta_(beta) {};
 
   /**
    * A primitive must know how to evaluate itself on the CPU/GPU
@@ -42,9 +42,9 @@ class Axpby : public Primitive {
    * To avoid unnecessary allocations, the evaluation function
    * is responsible for allocating space for the array.
    */
-  void eval_cpu(const std::vector<array>& inputs, std::vector<array>& out)
+  void eval_cpu(const std::vector<array>& inputs, std::vector<array>& outputs)
       override;
-  void eval_gpu(const std::vector<array>& inputs, std::vector<array>& out)
+  void eval_gpu(const std::vector<array>& inputs, std::vector<array>& outputs)
       override;
 
   /** The Jacobian-vector product. */
@@ -83,7 +83,7 @@ class Axpby : public Primitive {
   float beta_;
 
   /** Fall back implementation for evaluation on CPU */
-  void eval(const std::vector<array>& inputs, std::vector<array>& out);
+  void eval(const std::vector<array>& inputs, std::vector<array>& outputs);
 };
 
-} // namespace mlx::core
+} // namespace mlx::core

examples/extensions/axpby/axpby.metal

@@ -19,7 +19,7 @@ template <typename T>
     uint index [[thread_position_in_grid]]) {
   auto x_offset = elem_to_loc(index, shape, x_strides, ndim);
   auto y_offset = elem_to_loc(index, shape, y_strides, ndim);
-  out[index] = 
+  out[index] =
       static_cast<T>(alpha) * x[x_offset] + static_cast<T>(beta) * y[y_offset];
 }
 
@@ -31,30 +31,30 @@ template <typename T>
     constant const float& alpha [[buffer(3)]],
     constant const float& beta [[buffer(4)]],
     uint index [[thread_position_in_grid]]) {
-  out[index] = 
+  out[index] =
       static_cast<T>(alpha) * x[index] + static_cast<T>(beta) * y[index];
 }
 
-#define instantiate_axpby(type_name, type)            \
-  template [[host_name("axpby_general_" #type_name)]] \
-  [[kernel]] void axpby_general<type>(                \
-      device const type* x [[buffer(0)]],             \
-      device const type* y [[buffer(1)]],             \
-      device type* out [[buffer(2)]],                 \
-      constant const float& alpha [[buffer(3)]],      \
-      constant const float& beta [[buffer(4)]],       \
-      constant const int* shape [[buffer(5)]],        \
-      constant const size_t* x_strides [[buffer(6)]], \
-      constant const size_t* y_strides [[buffer(7)]], \
-      constant const int& ndim [[buffer(8)]],         \
-      uint index [[thread_position_in_grid]]);        \
-  template [[host_name("axpby_contiguous_" #type_name)]] \
-  [[kernel]] void axpby_contiguous<type>(                \
-      device const type* x [[buffer(0)]],                \
-      device const type* y [[buffer(1)]],                \
-      device type* out [[buffer(2)]],                    \
-      constant const float& alpha [[buffer(3)]],         \
-      constant const float& beta [[buffer(4)]],          \
+#define instantiate_axpby(type_name, type)                               \
+  template [[host_name("axpby_general_" #type_name)]] [[kernel]] void    \
+  axpby_general<type>(                                                   \
+      device const type* x [[buffer(0)]],                                \
+      device const type* y [[buffer(1)]],                                \
+      device type* out [[buffer(2)]],                                    \
+      constant const float& alpha [[buffer(3)]],                         \
+      constant const float& beta [[buffer(4)]],                          \
+      constant const int* shape [[buffer(5)]],                           \
+      constant const size_t* x_strides [[buffer(6)]],                    \
+      constant const size_t* y_strides [[buffer(7)]],                    \
+      constant const int& ndim [[buffer(8)]],                            \
+      uint index [[thread_position_in_grid]]);                           \
+  template [[host_name("axpby_contiguous_" #type_name)]] [[kernel]] void \
+  axpby_contiguous<type>(                                                \
+      device const type* x [[buffer(0)]],                                \
+      device const type* y [[buffer(1)]],                                \
+      device type* out [[buffer(2)]],                                    \
+      constant const float& alpha [[buffer(3)]],                         \
+      constant const float& beta [[buffer(4)]],                          \
       uint index [[thread_position_in_grid]]);
 
 instantiate_axpby(float32, float);

examples/extensions/bindings.cpp

@@ -1,31 +1,31 @@
-// Copyright © 2023 Apple Inc.
+// Copyright © 2023-2024 Apple Inc.
 
-#include <pybind11/pybind11.h>
-#include <pybind11/stl.h>
+#include <nanobind/nanobind.h>
+#include <nanobind/stl/variant.h>
 
 #include "axpby/axpby.h"
 
-namespace py = pybind11;
-using namespace py::literals;
+namespace nb = nanobind;
+using namespace nb::literals;
+
 using namespace mlx::core;
 
-PYBIND11_MODULE(mlx_sample_extensions, m) {
-  m.doc() = "Sample C++ and metal extensions for MLX";
+NB_MODULE(_ext, m) {
+  m.doc() = "Sample extension for MLX";
 
   m.def(
       "axpby",
       &axpby,
       "x"_a,
       "y"_a,
-      py::pos_only(),
       "alpha"_a,
       "beta"_a,
-      py::kw_only(),
-      "stream"_a = py::none(),
-      R"pbdoc(
+      nb::kw_only(),
+      "stream"_a = nb::none(),
+      R"(
         Scale and sum two vectors element-wise
         ``z = alpha * x + beta * y``
-        
+
         Follows numpy style broadcasting between ``x`` and ``y``
         Inputs are upcasted to floats if needed
 
@@ -37,5 +37,5 @@ PYBIND11_MODULE(mlx_sample_extensions, m) {
 
         Returns:
             array: ``alpha * x + beta * y``
-      )pbdoc");
-}
+      )");
+}

examples/extensions/mlx_sample_extensions/__init__.py

@@ -2,4 +2,4 @@
 
 import mlx.core as mx
 
-from .mlx_sample_extensions import *
+from ._ext import axpby

examples/extensions/pyproject.toml

@@ -1,3 +1,8 @@
 [build-system]
-requires = ["setuptools>=42", "pybind11>=2.10", "cmake>=3.24", "mlx @ git+https://github.com/mlx-explore/mlx@main"]
-build-backend = "setuptools.build_meta"
+requires = [
+  "setuptools>=42",
+  "cmake>=3.24",
+  "mlx>=0.17.0",
+  "nanobind==2.1.0",
+]
+build-backend = "setuptools.build_meta"

examples/extensions/requirements.txt

@@ -0,0 +1,4 @@
+setuptools>=42
+cmake>=3.24
+mlx>=0.17.0
+nanobind==2.1.0

examples/extensions/setup.py

@@ -1,4 +1,4 @@
-# Copyright © 2023 Apple Inc.
+# Copyright © 2023-2024 Apple Inc.
 
 from setuptools import setup
 
@@ -9,10 +9,9 @@ if __name__ == "__main__":
         name="mlx_sample_extensions",
         version="0.0.0",
         description="Sample C++ and Metal extensions for MLX primitives.",
-        ext_modules=[extension.CMakeExtension("mlx_sample_extensions")],
+        ext_modules=[extension.CMakeExtension("mlx_sample_extensions._ext")],
         cmdclass={"build_ext": extension.CMakeBuild},
         packages=["mlx_sample_extensions"],
-        package_dir={"": "."},
         package_data={"mlx_sample_extensions": ["*.so", "*.dylib", "*.metallib"]},
         zip_safe=False,
         python_requires=">=3.8",

examples/extensions/test.py

@@ -0,0 +1,10 @@
+import mlx.core as mx
+from mlx_sample_extensions import axpby
+
+a = mx.ones((3, 4))
+b = mx.ones((3, 4))
+c = axpby(a, b, 4.0, 2.0, stream=mx.cpu)
+
+print(f"c shape: {c.shape}")
+print(f"c dtype: {c.dtype}")
+print(f"c correct: {mx.all(c == 6.0).item()}")

mlx/CMakeLists.txt

@@ -3,9 +3,11 @@ target_sources(
   PRIVATE
   ${CMAKE_CURRENT_SOURCE_DIR}/allocator.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/array.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/compile.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/device.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/dtype.cpp
-  ${CMAKE_CURRENT_SOURCE_DIR}/compile.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/einsum.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/fast.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/fft.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/ops.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/graph_utils.cpp
@@ -18,11 +20,17 @@ target_sources(
   ${CMAKE_CURRENT_SOURCE_DIR}/backend/metal/metal.h
 )
 
-add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backend/common)
+if (MLX_BUILD_CPU)
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backend/common)
+else()
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backend/no_cpu)
+endif()
+
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/distributed)
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/io)
 if (MLX_BUILD_ACCELERATE)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backend/accelerate)
-else()
+elseif(MLX_BUILD_CPU)
   target_sources(
     mlx
     PRIVATE

mlx/allocator.h

@@ -14,7 +14,7 @@ class Buffer {
   void* ptr_;
 
  public:
-  Buffer(void* ptr) : ptr_(ptr){};
+  Buffer(void* ptr) : ptr_(ptr) {};
 
   // Get the raw data pointer from the buffer
   void* raw_ptr();

mlx/array.cpp

@@ -1,5 +1,4 @@
 // Copyright © 2023-2024 Apple Inc.
-
 #include <functional>
 
 #include "mlx/array.h"
@@ -12,22 +11,16 @@ namespace mlx::core {
 
 namespace {
 
-std::pair<size_t, std::vector<size_t>> cum_prod(const std::vector<int>& shape) {
-  std::vector<size_t> strides(shape.size());
-  size_t cum_prod = 1;
-  for (int i = shape.size() - 1; i >= 0; --i) {
-    strides[i] = cum_prod;
-    cum_prod *= shape[i];
-  }
-  return {cum_prod, strides};
-}
-
 /** Return true if we are currently performing a function transformation in
  * order to keep the graph when evaluating tracer arrays. */
 bool in_tracing() {
   return detail::InTracing::in_tracing();
 }
 
+bool retain_graph() {
+  return detail::RetainGraph::retain_graph();
+}
+
 } // namespace
 
 array::array(const std::complex<float>& val, Dtype dtype /* = complex64 */)
@@ -36,22 +29,11 @@ array::array(const std::complex<float>& val, Dtype dtype /* = complex64 */)
   init(&cval);
 }
 
-array::array(
-    const std::vector<int>& shape,
-    Dtype dtype,
-    std::shared_ptr<Primitive> primitive,
-    const std::vector<array>& inputs)
-    : array_desc_(std::make_shared<ArrayDesc>(
-          shape,
-          dtype,
-          std::move(primitive),
-          inputs)) {}
-
 array::array(
     std::vector<int> shape,
     Dtype dtype,
     std::shared_ptr<Primitive> primitive,
-    std::vector<array>&& inputs)
+    std::vector<array> inputs)
     : array_desc_(std::make_shared<ArrayDesc>(
           std::move(shape),
           dtype,
@@ -59,15 +41,16 @@ array::array(
           std::move(inputs))) {}
 
 std::vector<array> array::make_arrays(
-    const std::vector<std::vector<int>>& shapes,
+    std::vector<std::vector<int>> shapes,
     const std::vector<Dtype>& dtypes,
-    std::shared_ptr<Primitive> primitive,
+    const std::shared_ptr<Primitive>& primitive,
     const std::vector<array>& inputs) {
   std::vector<array> outputs;
-  for (int i = 0; i < shapes.size(); ++i) {
-    outputs.push_back(array(shapes[i], dtypes[i], primitive, inputs));
+  for (size_t i = 0; i < shapes.size(); ++i) {
+    outputs.emplace_back(std::move(shapes[i]), dtypes[i], primitive, inputs);
   }
-  for (int i = 0; i < outputs.size(); ++i) {
+  // For each node in |outputs|, its siblings are the other nodes.
+  for (size_t i = 0; i < outputs.size(); ++i) {
     auto siblings = outputs;
     siblings.erase(siblings.begin() + i);
     outputs[i].set_siblings(std::move(siblings), i);
@@ -82,13 +65,20 @@ array::array(std::initializer_list<float> data)
   init(data.begin());
 }
 
+array::array(std::initializer_list<int> data, Dtype dtype)
+    : array_desc_(std::make_shared<ArrayDesc>(
+          std::vector<int>{static_cast<int>(data.size())},
+          dtype)) {
+  init(data.begin());
+}
+
 /* Build an array from a shared buffer */
 array::array(
     allocator::Buffer data,
-    const std::vector<int>& shape,
+    std::vector<int> shape,
     Dtype dtype,
     deleter_t deleter)
-    : array_desc_(std::make_shared<ArrayDesc>(shape, dtype)) {
+    : array_desc_(std::make_shared<ArrayDesc>(std::move(shape), dtype)) {
   set_data(data, deleter);
 }
 
@@ -97,22 +87,26 @@ void array::detach() {
     s.array_desc_->inputs.clear();
     s.array_desc_->siblings.clear();
     s.array_desc_->position = 0;
-    s.array_desc_->depth = 0;
     s.array_desc_->primitive = nullptr;
   }
   array_desc_->inputs.clear();
   array_desc_->siblings.clear();
   array_desc_->position = 0;
-  array_desc_->depth = 0;
   array_desc_->primitive = nullptr;
 }
 
 void array::eval() {
-  mlx::core::eval({*this});
+  // Ensure the array is ready to be read
+  if (status() == Status::scheduled) {
+    event().wait();
+    set_status(Status::available);
+  } else if (status() == Status::unscheduled) {
+    mlx::core::eval({*this});
+  }
 }
 
 bool array::is_tracer() const {
-  return array_desc_->is_tracer && in_tracing();
+  return array_desc_->is_tracer && in_tracing() || retain_graph();
 }
 
 void array::set_data(allocator::Buffer buffer, deleter_t d) {
@@ -157,51 +151,117 @@ void array::copy_shared_buffer(const array& other) {
   copy_shared_buffer(other, other.strides(), other.flags(), other.data_size());
 }
 
-void array::move_shared_buffer(array other) {
+void array::move_shared_buffer(
+    array other,
+    const std::vector<size_t>& strides,
+    Flags flags,
+    size_t data_size,
+    size_t offset /* = 0 */) {
   array_desc_->data = std::move(other.array_desc_->data);
-  array_desc_->strides = other.strides();
-  array_desc_->flags = other.flags();
-  array_desc_->data_size = other.data_size();
-  array_desc_->data_ptr = other.array_desc_->data_ptr;
+  array_desc_->strides = strides;
+  array_desc_->flags = flags;
+  array_desc_->data_size = data_size;
+  auto char_offset = sizeof(char) * itemsize() * offset;
+  array_desc_->data_ptr = static_cast<void*>(
+      static_cast<char*>(other.array_desc_->data_ptr) + char_offset);
 }
 
-array::ArrayDesc::ArrayDesc(const std::vector<int>& shape, Dtype dtype)
-    : shape(shape), dtype(dtype) {
-  std::tie(size, strides) = cum_prod(shape);
+void array::move_shared_buffer(array other) {
+  move_shared_buffer(other, other.strides(), other.flags(), other.data_size());
 }
 
-array::ArrayDesc::ArrayDesc(
-    const std::vector<int>& shape,
-    Dtype dtype,
-    std::shared_ptr<Primitive> primitive,
-    const std::vector<array>& inputs)
-    : shape(shape),
-      dtype(dtype),
-      primitive(std::move(primitive)),
-      inputs(inputs) {
-  std::tie(size, strides) = cum_prod(this->shape);
-  for (auto& in : inputs) {
-    is_tracer |= in.is_tracer();
-    depth = std::max(in.graph_depth(), depth);
+array::~array() {
+  if (array_desc_ == nullptr) {
+    return;
   }
-  depth++;
+
+  // Ignore arrays that might be detached during eval
+  if (status() == array::Status::scheduled) {
+    return;
+  }
+
+  // Break circular reference for non-detached arrays with siblings
+  if (auto n = siblings().size(); n > 0) {
+    bool do_detach = true;
+    // If all siblings have siblings.size() references except
+    // the one we are currently destroying (which has siblings.size() + 1)
+    // then there are no more external references
+    do_detach &= (array_desc_.use_count() == (n + 1));
+    for (auto& s : siblings()) {
+      do_detach &= (s.array_desc_.use_count() == n);
+      if (!do_detach) {
+        break;
+      }
+    }
+    if (do_detach) {
+      for (auto& s : siblings()) {
+        for (auto& ss : s.siblings()) {
+          ss.array_desc_ = nullptr;
+        }
+        s.array_desc_->siblings.clear();
+      }
+    }
+  }
+}
+
+void array::ArrayDesc::init() {
+  strides.resize(shape.size());
+  size = 1;
+  for (int i = shape.size() - 1; i >= 0; --i) {
+    strides[i] = size;
+    size *= shape[i];
+  }
+  for (const auto& in : inputs) {
+    is_tracer |= in.is_tracer();
+  }
+}
+
+array::ArrayDesc::ArrayDesc(std::vector<int> shape, Dtype dtype)
+    : shape(std::move(shape)), dtype(dtype), status(Status::available) {
+  init();
 }
 
 array::ArrayDesc::ArrayDesc(
-    std::vector<int>&& shape,
+    std::vector<int> shape,
     Dtype dtype,
     std::shared_ptr<Primitive> primitive,
-    std::vector<array>&& inputs)
+    std::vector<array> inputs)
     : shape(std::move(shape)),
       dtype(dtype),
+      status(Status::unscheduled),
       primitive(std::move(primitive)),
       inputs(std::move(inputs)) {
-  std::tie(size, strides) = cum_prod(this->shape);
-  for (auto& in : inputs) {
-    is_tracer |= in.is_tracer();
-    depth = std::max(in.graph_depth(), depth);
+  init();
+}
+
+array::ArrayDesc::~ArrayDesc() {
+  // When an array description is destroyed it will delete a bunch of arrays
+  // that may also destroy their corresponding descriptions and so on and so
+  // forth.
+  //
+  // This calls recursively the destructor and can result in stack overflow, we
+  // instead put them in a vector and destroy them one at a time resulting in a
+  // max stack depth of 2.
+  std::vector<std::shared_ptr<ArrayDesc>> for_deletion;
+
+  for (array& a : inputs) {
+    if (a.array_desc_.use_count() == 1) {
+      for_deletion.push_back(std::move(a.array_desc_));
+    }
+  }
+
+  while (!for_deletion.empty()) {
+    // top is going to be deleted at the end of the block *after* the arrays
+    // with inputs have been moved into the vector
+    auto top = std::move(for_deletion.back());
+    for_deletion.pop_back();
+
+    for (array& a : top->inputs) {
+      if (a.array_desc_.use_count() == 1) {
+        for_deletion.push_back(std::move(a.array_desc_));
+      }
+    }
   }
-  depth++;
 }
 
 array::ArrayIterator::ArrayIterator(const array& arr, int idx)

mlx/array.h

@@ -1,5 +1,6 @@
 // Copyright © 2023 Apple Inc.
 #pragma once
+
 #include <algorithm>
 #include <cstdint>
 #include <functional>
@@ -8,6 +9,7 @@
 
 #include "mlx/allocator.h"
 #include "mlx/dtype.h"
+#include "mlx/event.h"
 
 namespace mlx::core {
 
@@ -31,7 +33,7 @@ class array {
   template <typename It>
   array(
       It data,
-      const std::vector<int>& shape,
+      std::vector<int> shape,
       Dtype dtype =
           TypeToDtype<typename std::iterator_traits<It>::value_type>());
 
@@ -41,16 +43,19 @@ class array {
   /* Special case so empty lists default to float32. */
   array(std::initializer_list<float> data);
 
+  /* Special case so array({}, type) is an empty array. */
+  array(std::initializer_list<int> data, Dtype dtype);
+
   template <typename T>
   array(
       std::initializer_list<T> data,
-      const std::vector<int>& shape,
+      std::vector<int> shape,
       Dtype dtype = TypeToDtype<T>());
 
   /* Build an array from a buffer */
   array(
       allocator::Buffer data,
-      const std::vector<int>& shape,
+      std::vector<int> shape,
       Dtype dtype,
       deleter_t deleter = allocator::free);
 
@@ -68,32 +73,32 @@ class array {
       this->array_desc_ = other.array_desc_;
     }
     return *this;
-  };
+  }
 
   /** The size of the array's datatype in bytes. */
   size_t itemsize() const {
     return size_of(dtype());
-  };
+  }
 
   /** The number of elements in the array. */
   size_t size() const {
     return array_desc_->size;
-  };
+  }
 
   /** The number of bytes in the array. */
   size_t nbytes() const {
     return size() * itemsize();
-  };
+  }
 
   /** The number of dimensions of the array. */
   size_t ndim() const {
     return array_desc_->shape.size();
-  };
+  }
 
   /** The shape of the array as a vector of integers. */
   const std::vector<int>& shape() const {
     return array_desc_->shape;
-  };
+  }
 
   /**
    *  Get the size of the corresponding dimension.
@@ -102,17 +107,26 @@ class array {
    *  bounds checking. */
   int shape(int dim) const {
     return shape().at(dim < 0 ? dim + ndim() : dim);
-  };
+  }
 
   /** The strides of the array. */
   const std::vector<size_t>& strides() const {
     return array_desc_->strides;
-  };
+  }
+
+  /**
+   *  Get the stride of the corresponding dimension.
+   *
+   *  This function supports negative indexing and provides
+   *  bounds checking. */
+  size_t strides(int dim) const {
+    return strides().at(dim < 0 ? dim + ndim() : dim);
+  }
 
   /** Get the arrays data type. */
   Dtype dtype() const {
     return array_desc_->dtype;
-  };
+  }
 
   /** Evaluate the array. */
   void eval();
@@ -121,6 +135,9 @@ class array {
   template <typename T>
   T item();
 
+  template <typename T>
+  T item() const;
+
   struct ArrayIterator {
     using iterator_category = std::random_access_iterator_tag;
     using difference_type = size_t;
@@ -143,10 +160,10 @@ class array {
 
     friend bool operator==(const ArrayIterator& a, const ArrayIterator& b) {
       return a.arr.id() == b.arr.id() && a.idx == b.idx;
-    };
+    }
     friend bool operator!=(const ArrayIterator& a, const ArrayIterator& b) {
       return !(a == b);
-    };
+    }
 
    private:
     const array& arr;
@@ -166,22 +183,16 @@ class array {
    * API may change.
    */
 
-  array(
-      const std::vector<int>& shape,
-      Dtype dtype,
-      std::shared_ptr<Primitive> primitive,
-      const std::vector<array>& inputs);
-
   array(
       std::vector<int> shape,
       Dtype dtype,
       std::shared_ptr<Primitive> primitive,
-      std::vector<array>&& inputs);
+      std::vector<array> inputs);
 
   static std::vector<array> make_arrays(
-      const std::vector<std::vector<int>>& shapes,
+      std::vector<std::vector<int>> shapes,
       const std::vector<Dtype>& dtypes,
-      std::shared_ptr<Primitive> primitive,
+      const std::shared_ptr<Primitive>& primitive,
       const std::vector<array>& inputs);
 
   /** A unique identifier for an array. */
@@ -198,7 +209,7 @@ class array {
     allocator::Buffer buffer;
     deleter_t d;
     Data(allocator::Buffer buffer, deleter_t d = allocator::free)
-        : buffer(buffer), d(d){};
+        : buffer(buffer), d(d) {}
     // Not copyable
     Data(const Data& d) = delete;
     Data& operator=(const Data& d) = delete;
@@ -219,22 +230,22 @@ class array {
   /** The array's primitive. */
   Primitive& primitive() const {
     return *(array_desc_->primitive);
-  };
+  }
 
   /** A shared pointer to the array's primitive. */
   std::shared_ptr<Primitive>& primitive_ptr() const {
     return array_desc_->primitive;
-  };
+  }
 
   /** Check if the array has an attached primitive or is a leaf node. */
   bool has_primitive() const {
     return array_desc_->primitive != nullptr;
-  };
+  }
 
   /** The array's inputs. */
   const std::vector<array>& inputs() const {
     return array_desc_->inputs;
-  };
+  }
 
   std::vector<array>& inputs() {
     return array_desc_->inputs;
@@ -248,7 +259,12 @@ class array {
   /** The array's siblings. */
   const std::vector<array>& siblings() const {
     return array_desc_->siblings;
-  };
+  }
+
+  /** The array's siblings. */
+  std::vector<array>& siblings() {
+    return array_desc_->siblings;
+  }
 
   void set_siblings(std::vector<array> siblings, uint16_t position) {
     array_desc_->siblings = std::move(siblings);
@@ -265,11 +281,6 @@ class array {
     outputs.push_back(*this);
     outputs.insert(outputs.end(), siblings().begin() + idx, siblings().end());
     return outputs;
-  };
-
-  /** The depth of the array in the graph. Evaluated arrays have depth 0. */
-  uint16_t graph_depth() const {
-    return array_desc_->depth;
   }
 
   /** Detach the array from the graph. */
@@ -278,19 +289,19 @@ class array {
   /** Get the Flags bit-field. */
   const Flags& flags() const {
     return array_desc_->flags;
-  };
+  }
 
   /** The size (in elements) of the underlying buffer the array points to. */
   size_t data_size() const {
     return array_desc_->data_size;
-  };
+  }
 
   allocator::Buffer& buffer() {
     return array_desc_->data->buffer;
-  };
+  }
   const allocator::Buffer& buffer() const {
     return array_desc_->data->buffer;
-  };
+  }
 
   // Return a copy of the shared pointer
   // to the array::Data struct
@@ -301,16 +312,35 @@ class array {
   template <typename T>
   T* data() {
     return static_cast<T*>(array_desc_->data_ptr);
-  };
+  }
 
   template <typename T>
   const T* data() const {
     return static_cast<T*>(array_desc_->data_ptr);
-  };
+  }
 
-  // Check if the array has been evaluated
-  bool is_evaled() const {
-    return array_desc_->data != nullptr;
+  enum Status { unscheduled, scheduled, available };
+
+  bool is_available() const {
+    return status() == Status::available;
+  }
+
+  Status status() const {
+    return array_desc_->status;
+  }
+
+  void set_status(Status s) const {
+    array_desc_->status = s;
+  }
+
+  // Get the array's shared event
+  Event& event() const {
+    return array_desc_->event;
+  }
+
+  // Attach an event to a not yet evaluated array
+  void attach_event(Event e) const {
+    array_desc_->event = std::move(e);
   }
 
   // Mark the array as a tracer array (true) or not.
@@ -338,12 +368,21 @@ class array {
 
   void copy_shared_buffer(const array& other);
 
+  void move_shared_buffer(
+      array other,
+      const std::vector<size_t>& strides,
+      Flags flags,
+      size_t data_size,
+      size_t offset = 0);
+
   void move_shared_buffer(array other);
 
   void overwrite_descriptor(const array& other) {
     array_desc_ = other.array_desc_;
   }
 
+  ~array();
+
  private:
   // Initialize the arrays data
   template <typename It>
@@ -354,7 +393,12 @@ class array {
     std::vector<size_t> strides;
     size_t size;
     Dtype dtype;
-    std::shared_ptr<Primitive> primitive{nullptr};
+    std::shared_ptr<Primitive> primitive;
+
+    Status status;
+
+    // An event on the array used for synchronization
+    Event event;
 
     // Indicates an array is being used in a graph transform
     // and should not be detached from the graph
@@ -362,7 +406,7 @@ class array {
 
     // This is a shared pointer so that *different* arrays
     // can share the underlying data buffer.
-    std::shared_ptr<Data> data{nullptr};
+    std::shared_ptr<Data> data;
 
     // Properly offset data pointer
     void* data_ptr{nullptr};
@@ -382,29 +426,26 @@ class array {
     // The arrays position in the output list
     uint32_t position{0};
 
-    // The depth of the array in the graph.
-    uint16_t depth{0};
-
-    explicit ArrayDesc(const std::vector<int>& shape, Dtype dtype);
+    explicit ArrayDesc(std::vector<int> shape, Dtype dtype);
 
     explicit ArrayDesc(
-        const std::vector<int>& shape,
+        std::vector<int> shape,
         Dtype dtype,
         std::shared_ptr<Primitive> primitive,
-        const std::vector<array>& inputs);
+        std::vector<array> inputs);
 
-    explicit ArrayDesc(
-        std::vector<int>&& shape,
-        Dtype dtype,
-        std::shared_ptr<Primitive> primitive,
-        std::vector<array>&& inputs);
+    ~ArrayDesc();
+
+   private:
+    // Initialize size, strides, and other metadata
+    void init();
   };
 
   // The ArrayDesc contains the details of the materialized array including the
   // shape, strides, the data type. It also includes
   // the primitive which knows how to compute the array's data from its inputs
   // and the list of array's inputs for the primitive.
-  std::shared_ptr<ArrayDesc> array_desc_{nullptr};
+  std::shared_ptr<ArrayDesc> array_desc_;
 };
 
 template <typename T>
@@ -416,9 +457,9 @@ array::array(T val, Dtype dtype /* = TypeToDtype<T>() */)
 template <typename It>
 array::array(
   It data,
-  const std::vector<int>& shape,
+  std::vector<int> shape,
   Dtype dtype /* = TypeToDtype<typename std::iterator_traits<It>::value_type>() */) :
-    array_desc_(std::make_shared<ArrayDesc>(shape, dtype)) {
+    array_desc_(std::make_shared<ArrayDesc>(std::move(shape), dtype)) {
   init(data);
 }
 
@@ -435,9 +476,9 @@ array::array(
 template <typename T>
 array::array(
     std::initializer_list<T> data,
-    const std::vector<int>& shape,
+    std::vector<int> shape,
     Dtype dtype /* = TypeToDtype<T>() */)
-    : array_desc_(std::make_shared<ArrayDesc>(shape, dtype)) {
+    : array_desc_(std::make_shared<ArrayDesc>(std::move(shape), dtype)) {
   if (data.size() != size()) {
     throw std::invalid_argument(
         "Data size and provided shape mismatch in array construction.");
@@ -454,6 +495,19 @@ T array::item() {
   return *data<T>();
 }
 
+template <typename T>
+T array::item() const {
+  if (size() != 1) {
+    throw std::invalid_argument("item can only be called on arrays of size 1.");
+  }
+  if (status() == Status::unscheduled) {
+    throw std::invalid_argument(
+        "item() const can only be called on evaled arrays");
+  }
+  const_cast<array*>(this)->eval();
+  return *data<T>();
+}
+
 template <typename It>
 void array::init(It src) {
   set_data(allocator::malloc(size() * size_of(dtype())));
@@ -500,4 +554,15 @@ void array::init(It src) {
   }
 }
 
+/* Utilities for determining whether a template parameter is array. */
+template <typename T>
+inline constexpr bool is_array_v =
+    std::is_same_v<std::remove_cv_t<std::remove_reference_t<T>>, array>;
+
+template <typename... T>
+inline constexpr bool is_arrays_v = (is_array_v<T> && ...);
+
+template <typename... T>
+using enable_for_arrays_t = typename std::enable_if_t<is_arrays_v<T...>>;
+
 } // namespace mlx::core

mlx/backend/accelerate/conv.cpp

@@ -1,9 +1,9 @@
-// Copyright © 2023 Apple Inc.
+// Copyright © 2023-2024 Apple Inc.
 
 #include <cassert>
 
+#include <Accelerate/Accelerate.h>
 #include <simd/vector.h>
-#include <vecLib/vDSP.h>
 
 #include "mlx/backend/common/copy.h"
 #include "mlx/primitives.h"

mlx/backend/accelerate/matmul.cpp

@@ -1,9 +1,8 @@
-// Copyright © 2023 Apple Inc.
+// Copyright © 2023-2024 Apple Inc.
 
 #include <cassert>
 
-#include <vecLib/BNNS/bnns.h>
-#include <vecLib/cblas_new.h>
+#include <Accelerate/Accelerate.h>
 
 #include "mlx/backend/accelerate/utils.h"
 #include "mlx/backend/common/copy.h"
@@ -46,6 +45,9 @@ inline void matmul_cblas_general(
   size_t N = b.shape(-1);
   size_t K = a.shape(-1);
 
+  if (M == 0 || N == 0) {
+    return;
+  }
   if (K == 0) {
     std::memset(static_cast<void*>(out.data<float>()), 0, out.nbytes());
     return;
@@ -94,6 +96,9 @@ inline void matmul_bnns_general(
   size_t N = b.shape(-1);
   size_t K = a.shape(-1);
 
+  if (M == 0 || N == 0) {
+    return;
+  }
   if (K == 0) {
     std::memset(static_cast<void*>(out.data<float>()), 0, out.nbytes());
     return;
@@ -190,6 +195,40 @@ inline void matmul_bnns(const array& a_pre, const array& b_pre, array& out) {
   return matmul_bnns_general(a_pre, b_pre, out);
 }
 
+template <typename T>
+inline void mask_matrix(
+    T* data,
+    const bool* mask,
+    int tile_size,
+    const int X,
+    const int Y,
+    const size_t X_data_str,
+    const size_t Y_data_str,
+    const size_t X_mask_str,
+    const size_t Y_mask_str) {
+  int tX = (X + tile_size - 1) / tile_size;
+  int tY = (Y + tile_size - 1) / tile_size;
+
+  for (int i = 0; i < tX; i++) {
+    for (int j = 0; j < tY; j++) {
+      bool do_mask = mask[i * X_mask_str + j * Y_mask_str];
+      if (!do_mask) {
+        int loc_x = i * tile_size;
+        int loc_y = j * tile_size;
+        T* data_block = data + loc_x * X_data_str + loc_y * Y_data_str;
+
+        int size_x = std::min(tile_size, X - loc_x);
+        int size_y = std::min(tile_size, Y - loc_y);
+        for (int ii = 0; ii < size_x; ii++) {
+          for (int jj = 0; jj < size_y; jj++) {
+            data_block[ii * X_data_str + jj * Y_data_str] = T(0.);
+          }
+        }
+      }
+    }
+  }
+}
+
 } // namespace
 
 void Matmul::eval_cpu(const std::vector<array>& inputs, array& out) {

mlx/backend/accelerate/primitives.cpp

@@ -3,8 +3,7 @@
 #include <cassert>
 #include <cmath>
 
-#include <vecLib/vDSP.h>
-#include <vecLib/vForce.h>
+#include <Accelerate/Accelerate.h>
 
 #include "mlx/allocator.h"
 #include "mlx/backend/common/binary.h"
@@ -31,20 +30,27 @@ DEFAULT(ArgPartition)
 DEFAULT(ArgReduce)
 DEFAULT(ArgSort)
 DEFAULT(AsStrided)
+DEFAULT(BlockMaskedMM)
 DEFAULT(Broadcast)
 DEFAULT(Ceil)
 DEFAULT(Concatenate)
+DEFAULT(Conjugate)
 DEFAULT(Copy)
-DEFAULT_MULTI(CustomVJP)
+DEFAULT_MULTI(CustomTransforms)
 DEFAULT_MULTI(Depends)
+DEFAULT_MULTI(DivMod)
+DEFAULT(NumberOfElements)
 DEFAULT(Equal)
 DEFAULT(Erf)
 DEFAULT(ErfInv)
 DEFAULT(FFT)
 DEFAULT(Floor)
 DEFAULT(Gather)
+DEFAULT(GatherMM)
+DEFAULT(GatherQMM)
 DEFAULT(Greater)
 DEFAULT(GreaterEqual)
+DEFAULT(Hadamard)
 DEFAULT(Less)
 DEFAULT(LessEqual)
 DEFAULT(Load)
@@ -57,19 +63,24 @@ DEFAULT(Minimum)
 DEFAULT(NotEqual)
 DEFAULT(Pad)
 DEFAULT(Partition)
+DEFAULT_MULTI(QRF)
 DEFAULT(RandomBits)
 DEFAULT(Reshape)
+DEFAULT(Remainder)
 DEFAULT(Round)
 DEFAULT(Scatter)
+DEFAULT(Select)
 DEFAULT(Sigmoid)
 DEFAULT(Sign)
 DEFAULT(Slice)
+DEFAULT(SliceUpdate)
 DEFAULT_MULTI(Split)
 DEFAULT(Sort)
 DEFAULT(StopGradient)
+DEFAULT_MULTI(SVD)
 DEFAULT(Transpose)
-DEFAULT_MULTI(DivMod)
-DEFAULT_MULTI(QRF)
+DEFAULT(Inverse)
+DEFAULT(Cholesky)
 
 void Abs::eval_cpu(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 1);
@@ -80,11 +91,8 @@ void Abs::eval_cpu(const std::vector<array>& inputs, array& out) {
   } else if (in.dtype() == int32 && in.flags().contiguous) {
     set_unary_output_data(in, out);
     vDSP_vabsi(in.data<int>(), 1, out.data<int>(), 1, in.data_size());
-  } else if (is_unsigned(in.dtype())) {
-    // No-op for unsigned types
-    out.copy_shared_buffer(in);
   } else {
-    unary(in, out, AbsOp());
+    eval(inputs, out);
   }
 }
 
@@ -94,7 +102,7 @@ void Add::eval_cpu(const std::vector<array>& inputs, array& out) {
   auto& b = inputs[1];
 
   if (a.dtype() == float32) {
-    binary(
+    binary_op<float>(
         a,
         b,
         out,
@@ -109,7 +117,7 @@ void Add::eval_cpu(const std::vector<array>& inputs, array& out) {
           vDSP_vadd((const float*)a, 1, (const float*)b, 1, (float*)o, 1, n);
         });
   } else if (a.dtype() == int32) {
-    binary(
+    binary_op<int>(
         a,
         b,
         out,
@@ -124,7 +132,7 @@ void Add::eval_cpu(const std::vector<array>& inputs, array& out) {
           vDSP_vaddi((const int*)a, 1, (const int*)b, 1, (int*)o, 1, n);
         });
   } else {
-    binary(a, b, out, [](auto x, auto y) { return x + y; });
+    eval(inputs, out);
   }
 }
 
@@ -188,6 +196,26 @@ void ArcTan::eval_cpu(const std::vector<array>& inputs, array& out) {
   }
 }
 
+void ArcTan2::eval_cpu(const std::vector<array>& inputs, array& out) {
+  assert(inputs.size() == 2);
+  auto& a = inputs[0];
+  auto& b = inputs[1];
+  if (out.dtype() == float32 && a.flags().row_contiguous &&
+      b.flags().row_contiguous) {
+    if (a.is_donatable()) {
+      out.copy_shared_buffer(a);
+    } else if (b.is_donatable()) {
+      out.copy_shared_buffer(b);
+    } else {
+      out.set_data(allocator::malloc_or_wait(out.nbytes()));
+    }
+    int size = a.data_size();
+    vvatan2f(out.data<float>(), a.data<float>(), b.data<float>(), &size);
+  } else {
+    eval(inputs, out);
+  }
+}
+
 void ArcTanh::eval_cpu(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 1);
   const auto& in = inputs[0];
@@ -259,7 +287,7 @@ void Divide::eval_cpu(const std::vector<array>& inputs, array& out) {
   auto& b = inputs[1];
 
   if (a.dtype() == int32) {
-    binary(
+    binary_op<int>(
         a,
         b,
         out,
@@ -272,7 +300,7 @@ void Divide::eval_cpu(const std::vector<array>& inputs, array& out) {
           vDSP_vdivi((const int*)b, 1, (const int*)a, 1, (int*)o, 1, n);
         });
   } else if (a.dtype() == float32) {
-    binary(
+    binary_op<float>(
         a,
         b,
         out,
@@ -287,46 +315,7 @@ void Divide::eval_cpu(const std::vector<array>& inputs, array& out) {
           vDSP_vdiv((const float*)b, 1, (const float*)a, 1, (float*)o, 1, n);
         });
   } else {
-    binary(a, b, out, [](auto x, auto y) { return x / y; });
-  }
-}
-
-// TODO: Avoid code duplication with the common backend.
-struct RemainderFn {
-  template <typename T>
-  std::enable_if_t<!std::is_integral_v<T>, T> operator()(
-      T numerator,
-      T denominator) {
-    return std::fmod(numerator, denominator);
-  }
-
-  template <typename T>
-  std::enable_if_t<std::is_integral_v<T>, T> operator()(
-      T numerator,
-      T denominator) {
-    return numerator % denominator;
-  }
-};
-
-void Remainder::eval_cpu(const std::vector<array>& inputs, array& out) {
-  assert(inputs.size() == 2);
-  auto& a = inputs[0];
-  auto& b = inputs[1];
-
-  if (a.dtype() == float32) {
-    binary(
-        a,
-        b,
-        out,
-        RemainderFn{},
-        UseDefaultBinaryOp(),
-        UseDefaultBinaryOp(),
-        [](const auto* a, const auto* b, auto* o, auto n) {
-          int num_el = n;
-          vvremainderf((float*)o, (const float*)a, (const float*)b, &num_el);
-        });
-  } else {
-    binary(a, b, out, RemainderFn{});
+    eval(inputs, out);
   }
 }
 
@@ -337,12 +326,21 @@ void Exp::eval_cpu(const std::vector<array>& inputs, array& out) {
     set_unary_output_data(in, out);
     auto size = in.data_size();
     vvexpf(out.data<float>(), in.data<float>(), reinterpret_cast<int*>(&size));
-  } else if (is_floating_point(out.dtype())) {
-    unary_fp(in, out, [](auto x) { return std::exp(x); });
   } else {
-    throw std::invalid_argument(
-        "[exp] Cannot exponentiate elements in array"
-        " with non floating point type.");
+    eval(inputs, out);
+  }
+}
+
+void Expm1::eval_cpu(const std::vector<array>& inputs, array& out) {
+  assert(inputs.size() == 1);
+  const auto& in = inputs[0];
+  if (out.dtype() == float32 && in.flags().contiguous) {
+    set_unary_output_data(in, out);
+    auto size = in.data_size();
+    vvexpm1f(
+        out.data<float>(), in.data<float>(), reinterpret_cast<int*>(&size));
+  } else {
+    eval(inputs, out);
   }
 }
 
@@ -391,12 +389,8 @@ void Log1p::eval_cpu(const std::vector<array>& inputs, array& out) {
     auto size = in.data_size();
     vvlog1pf(
         out.data<float>(), in.data<float>(), reinterpret_cast<int*>(&size));
-  } else if (is_floating_point(out.dtype())) {
-    unary_fp(in, out, [](auto x) { return std::log1p(x); });
   } else {
-    throw std::invalid_argument(
-        "[log1p] Cannot compute log of elements in array with"
-        " non floating point type.");
+    eval(inputs, out);
   }
 }
 
@@ -406,7 +400,7 @@ void Multiply::eval_cpu(const std::vector<array>& inputs, array& out) {
   auto& b = inputs[1];
 
   if (a.dtype() == float32) {
-    binary(
+    binary_op<float>(
         a,
         b,
         out,
@@ -421,7 +415,7 @@ void Multiply::eval_cpu(const std::vector<array>& inputs, array& out) {
           vDSP_vmul((const float*)a, 1, (const float*)b, 1, (float*)o, 1, n);
         });
   } else {
-    binary(a, b, out, [](auto x, auto y) { return x * y; });
+    eval(inputs, out);
   }
 }
 
@@ -432,7 +426,7 @@ void Negative::eval_cpu(const std::vector<array>& inputs, array& out) {
     set_unary_output_data(in, out);
     vDSP_vneg(in.data<float>(), 1, out.data<float>(), 1, in.data_size());
   } else {
-    unary(in, out, [](auto x) { return -x; });
+    eval(inputs, out);
   }
 }
 
@@ -519,7 +513,7 @@ void Square::eval_cpu(const std::vector<array>& inputs, array& out) {
     auto size = in.data_size();
     vDSP_vsq(in.data<float>(), 1, out.data<float>(), 1, size);
   } else {
-    unary(in, out, [](auto x) { return x * x; });
+    eval(inputs, out);
   }
 }
 
@@ -545,7 +539,7 @@ void Subtract::eval_cpu(const std::vector<array>& inputs, array& out) {
   auto& b = inputs[1];
 
   if (a.dtype() == float32) {
-    binary(
+    binary_op<float>(
         a,
         b,
         out,
@@ -563,7 +557,7 @@ void Subtract::eval_cpu(const std::vector<array>& inputs, array& out) {
           vDSP_vsub((const float*)b, 1, (const float*)a, 1, (float*)o, 1, n);
         });
   } else if (a.dtype() == int32) {
-    binary(
+    binary_op<int>(
         a,
         b,
         out,
@@ -575,7 +569,7 @@ void Subtract::eval_cpu(const std::vector<array>& inputs, array& out) {
         },
         UseDefaultBinaryOp());
   } else {
-    binary(a, b, out, [](auto x, auto y) { return x - y; });
+    eval(inputs, out);
   }
 }
 

mlx/backend/accelerate/quantized.cpp

@@ -24,8 +24,6 @@ void _qmm_t_4_64(
   constexpr int bitmask = (1 << bits) - 1;
   constexpr int pack_factor = 32 / bits;
   constexpr int packs_in_group = group_size / pack_factor;
-  const int Kg = K / group_size;
-  const int Kw = K / pack_factor;
 
   for (int m = 0; m < M; m++) {
     const uint32_t* w_local = w;

mlx/backend/accelerate/reduce.cpp

@@ -2,86 +2,73 @@
 
 #include <cassert>
 
+#include <Accelerate/Accelerate.h>
 #include <simd/vector.h>
-#include <vecLib/vDSP.h>
 
 #include "mlx/backend/common/reduce.h"
 #include "mlx/primitives.h"
 
 namespace mlx::core {
 
-template <typename T, typename VT, int N>
-void _vectorized_strided_sum(const T* x, T* accum, int size, size_t stride) {
-  for (int i = 0; i < size; i++) {
-    size_t s = stride;
-    T* a = accum;
-    while (s >= N) {
-      VT val = (*(VT*)x);
-      *(VT*)a += val;
-      x += N;
-      a += N;
-      s -= N;
-    }
-    while (s-- > 0) {
-      *a++ += *x++;
-    }
-  }
-}
+namespace {
 
-// TODO: Add proper templates for the strided reduce algorithm so we don't have
-// to write max/min/sum etc.
-template <typename T, typename VT, int N>
-void _vectorized_strided_max(const T* x, T* accum, int size, size_t stride) {
-  for (int i = 0; i < size; i++) {
-    size_t s = stride;
-    T* a = accum;
-    while (s >= N) {
-      *(VT*)a = simd_max((*(VT*)x), (*(VT*)a));
-      x += N;
-      a += N;
-      s -= N;
-    }
-    while (s-- > 0) {
-      *a = std::max(*a, *x);
-      a++;
-      x++;
-    }
+template <typename T, typename VT>
+struct MinReduction {
+  T operator()(const T& a, const T& b) {
+    return std::min(a, b);
   }
-}
 
-template <typename T, typename VT, int N>
-void _vectorized_strided_min(const T* x, T* accum, int size, size_t stride) {
-  for (int i = 0; i < size; i++) {
-    size_t s = stride;
-    T* a = accum;
-    while (s >= N) {
-      *(VT*)a = simd_min((*(VT*)x), (*(VT*)a));
-      x += N;
-      a += N;
-      s -= N;
-    }
-    while (s-- > 0) {
-      *a = std::min(*a, *x);
-      a++;
-      x++;
-    }
+  VT operator()(VT a, VT b) {
+    return simd_min(a, b);
   }
-}
+};
 
-template <typename T, typename VT, int N>
-void _vectorized_sum(const T* x, T* accum, int size) {
-  VT _sum = {0};
-  while (size >= N) {
-    _sum += (*(VT*)x);
-    x += N;
-    size -= N;
+template <typename T, typename VT>
+struct MaxReduction {
+  T operator()(const T& a, const T& b) {
+    return std::max(a, b);
   }
-  T sum = _sum[0];
-  for (int i = 1; i < N; i++) {
-    sum += _sum[i];
+
+  VT operator()(VT a, VT b) {
+    return simd_max(a, b);
   }
-  *accum += sum;
-}
+};
+
+template <typename T, typename VT>
+struct SumReduction {
+  T operator()(const T& a, const T& b) {
+    return a + b;
+  }
+
+  VT operator()(VT a, VT b) {
+    return a + b;
+  }
+};
+
+template <typename T, typename VT, int N, typename Reduction>
+struct StridedReduce {
+  void operator()(const T* x, T* accum, int size, size_t stride) {
+    Reduction op;
+
+    for (int i = 0; i < size; i++) {
+      size_t s = stride;
+      T* a = accum;
+      while (s >= N) {
+        *(VT*)a = op((*(VT*)x), (*(VT*)a));
+        x += N;
+        a += N;
+        s -= N;
+      }
+      while (s-- > 0) {
+        *a = op(*a, *x);
+        a++;
+        x++;
+      }
+    }
+  }
+};
+
+} // namespace
 
 void Reduce::eval_cpu(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 1);
@@ -94,10 +81,11 @@ void Reduce::eval_cpu(const std::vector<array>& inputs, array& out) {
           out,
           axes_,
           0,
-          [](const auto* x, auto* accum, int size, size_t stride) {
-            _vectorized_strided_sum<float, simd_float16, 16>(
-                (const float*)x, (float*)accum, size, stride);
-          },
+          StridedReduce<
+              float,
+              simd_float16,
+              16,
+              SumReduction<float, simd_float16>>(),
           [](const auto* x, auto* accum, int size) {
             float acc;
             vDSP_sve((const float*)x, 1, &acc, size);
@@ -111,10 +99,11 @@ void Reduce::eval_cpu(const std::vector<array>& inputs, array& out) {
           out,
           axes_,
           -std::numeric_limits<float>::infinity(),
-          [](const auto* x, auto* accum, int size, size_t stride) {
-            _vectorized_strided_max<float, simd_float16, 16>(
-                (const float*)x, (float*)accum, size, stride);
-          },
+          StridedReduce<
+              float,
+              simd_float16,
+              16,
+              MaxReduction<float, simd_float16>>(),
           [](const auto* x, auto* accum, int size) {
             float max;
             vDSP_maxv((const float*)x, 1, &max, size);
@@ -128,10 +117,11 @@ void Reduce::eval_cpu(const std::vector<array>& inputs, array& out) {
           out,
           axes_,
           std::numeric_limits<float>::infinity(),
-          [](const auto* x, auto* accum, int size, size_t stride) {
-            _vectorized_strided_min<float, simd_float16, 16>(
-                (const float*)x, (float*)accum, size, stride);
-          },
+          StridedReduce<
+              float,
+              simd_float16,
+              16,
+              MinReduction<float, simd_float16>>(),
           [](const auto* x, auto* accum, int size) {
             float min;
             vDSP_minv((const float*)x, 1, &min, size);

mlx/backend/accelerate/softmax.cpp

@@ -1,9 +1,12 @@
-// Copyright © 2023 Apple Inc.
+// Copyright © 2023-2024 Apple Inc.
 
 #include <cassert>
 #include <limits>
 
+#if __ARM_FEATURE_FP16_VECTOR_ARITHMETIC
 #include <arm_neon.h>
+#endif
+
 #include <simd/math.h>
 #include <simd/vector.h>
 
@@ -53,25 +56,26 @@ inline simd_float16 simd_fast_exp(simd_float16 x) {
   return (*(simd_float16*)&epart) * x;
 }
 
+#if __ARM_FEATURE_FP16_VECTOR_ARITHMETIC
 /**
  * The ARM neon equivalent of the fast exp above.
  */
 inline float16x8_t neon_fast_exp(float16x8_t x) {
-  x = vmulq_f16(x, vdupq_n_f16(1.442695)); // multiply with log_2(e)
-  x = vmaxq_f16(x, vdupq_n_f16(-14)); // clamp under with -14
-  x = vminq_f16(x, vdupq_n_f16(14)); // clamp over with 14
+  x = vmulq_f16(x, vdupq_n_f16(float16_t(1.442695f))); // multiply with log_2(e)
+  x = vmaxq_f16(x, vdupq_n_f16(float16_t(-14.f))); // clamp under with -14
+  x = vminq_f16(x, vdupq_n_f16(float16_t(14.f))); // clamp over with 14
 
-  float16x8_t ipart = vrndmq_f16(vaddq_f16(x, vdupq_n_f16(0.5)));
+  float16x8_t ipart = vrndmq_f16(vaddq_f16(x, vdupq_n_f16(float16_t(0.5f))));
   float16x8_t fpart = vsubq_f16(x, ipart);
 
-  x = vdupq_n_f16(1.535336188319500e-4f);
-  x = vfmaq_f16(vdupq_n_f16(1.339887440266574e-3f), x, fpart);
-  x = vfmaq_f16(vdupq_n_f16(1.339887440266574e-3f), x, fpart);
-  x = vfmaq_f16(vdupq_n_f16(9.618437357674640e-3f), x, fpart);
-  x = vfmaq_f16(vdupq_n_f16(5.550332471162809e-2f), x, fpart);
-  x = vfmaq_f16(vdupq_n_f16(2.402264791363012e-1f), x, fpart);
-  x = vfmaq_f16(vdupq_n_f16(6.931472028550421e-1f), x, fpart);
-  x = vfmaq_f16(vdupq_n_f16(1.000000000000000f), x, fpart);
+  x = vdupq_n_f16(float16_t(1.535336188319500e-4f));
+  x = vfmaq_f16(vdupq_n_f16(float16_t(1.339887440266574e-3f)), x, fpart);
+  x = vfmaq_f16(vdupq_n_f16(float16_t(1.339887440266574e-3f)), x, fpart);
+  x = vfmaq_f16(vdupq_n_f16(float16_t(9.618437357674640e-3f)), x, fpart);
+  x = vfmaq_f16(vdupq_n_f16(float16_t(5.550332471162809e-2f)), x, fpart);
+  x = vfmaq_f16(vdupq_n_f16(float16_t(2.402264791363012e-1f)), x, fpart);
+  x = vfmaq_f16(vdupq_n_f16(float16_t(6.931472028550421e-1f)), x, fpart);
+  x = vfmaq_f16(vdupq_n_f16(float16_t(1.000000000000000f)), x, fpart);
 
   // generate 2**ipart in the floating point representation using integer
   // bitshifting
@@ -107,53 +111,6 @@ inline float16_t neon_reduce_add(float16x8_t x) {
   return vget_lane_f16(y, 0);
 }
 
-template <typename T, typename VT>
-struct AccelerateSimdOps {
-  VT init(T a) {
-    return a;
-  }
-
-  VT load(const T* a) {
-    return *(VT*)a;
-  }
-
-  void store(T* dst, VT x) {
-    *(VT*)dst = x;
-  }
-
-  VT max(VT a, VT b) {
-    return simd_max(a, b);
-  };
-
-  VT exp(VT x) {
-    return simd_fast_exp(x);
-  }
-
-  VT add(VT a, VT b) {
-    return a + b;
-  }
-
-  VT sub(VT a, T b) {
-    return a - b;
-  }
-
-  VT mul(VT a, VT b) {
-    return a * b;
-  }
-
-  VT mul(VT a, T b) {
-    return a * b;
-  }
-
-  T reduce_max(VT x) {
-    return simd_reduce_max(x);
-  }
-
-  T reduce_add(VT x) {
-    return simd_reduce_add(x);
-  }
-};
-
 template <typename T, typename VT>
 struct NeonFp16SimdOps {
   VT init(T a) {
@@ -170,7 +127,7 @@ struct NeonFp16SimdOps {
 
   VT max(VT a, VT b) {
     return vmaxq_f16(a, b);
-  };
+  }
 
   VT exp(VT x) {
     return neon_fast_exp(x);
@@ -201,7 +158,56 @@ struct NeonFp16SimdOps {
   }
 };
 
-template <typename T, typename VT, typename Ops, int N>
+#endif // __ARM_FEATURE_FP16_VECTOR_ARITHMETIC
+
+template <typename T, typename VT>
+struct AccelerateSimdOps {
+  VT init(T a) {
+    return a;
+  }
+
+  VT load(const T* a) {
+    return *(VT*)a;
+  }
+
+  void store(T* dst, VT x) {
+    *(VT*)dst = x;
+  }
+
+  VT max(VT a, VT b) {
+    return simd_max(a, b);
+  }
+
+  VT exp(VT x) {
+    return simd_fast_exp(x);
+  }
+
+  VT add(VT a, VT b) {
+    return a + b;
+  }
+
+  VT sub(VT a, T b) {
+    return a - b;
+  }
+
+  VT mul(VT a, VT b) {
+    return a * b;
+  }
+
+  VT mul(VT a, T b) {
+    return a * b;
+  }
+
+  T reduce_max(VT x) {
+    return simd_reduce_max(x);
+  }
+
+  T reduce_add(VT x) {
+    return simd_reduce_add(x);
+  }
+};
+
+template <typename T, typename AccT, typename VT, typename Ops, int N>
 void softmax(const array& in, array& out) {
   Ops ops;
 
@@ -218,13 +224,21 @@ void softmax(const array& in, array& out) {
     VT vmaximum = ops.init(-std::numeric_limits<float>::infinity());
     size_t s = M;
     while (s >= N) {
-      vmaximum = ops.max(ops.load(current_in_ptr), vmaximum);
+      VT vals;
+      if constexpr (std::is_same<T, AccT>::value) {
+        vals = ops.load(current_in_ptr);
+      } else {
+        for (int i = 0; i < N; ++i) {
+          vals[i] = static_cast<AccT>(current_in_ptr[i]);
+        }
+      }
+      vmaximum = ops.max(vals, vmaximum);
       current_in_ptr += N;
       s -= N;
     }
-    T maximum = ops.reduce_max(vmaximum);
+    AccT maximum = ops.reduce_max(vmaximum);
     while (s-- > 0) {
-      maximum = std::max(maximum, *current_in_ptr);
+      maximum = std::max(maximum, static_cast<AccT>(*current_in_ptr));
       current_in_ptr++;
     }
 
@@ -234,18 +248,29 @@ void softmax(const array& in, array& out) {
     current_in_ptr = in_ptr;
     s = M;
     while (s >= N) {
-      VT vexp = ops.exp(ops.sub(*(VT*)current_in_ptr, maximum));
-      ops.store(current_out_ptr, vexp);
-      *(VT*)current_out_ptr = vexp;
+      VT vexp;
+      if constexpr (std::is_same<T, AccT>::value) {
+        vexp = ops.load(current_in_ptr);
+      } else {
+        for (int i = 0; i < N; ++i) {
+          vexp[i] = static_cast<AccT>(current_in_ptr[i]);
+        }
+      }
+      vexp = ops.exp(ops.sub(vexp, maximum));
+      if constexpr (std::is_same<T, AccT>::value) {
+        ops.store(current_out_ptr, vexp);
+      }
       vnormalizer = ops.add(vnormalizer, vexp);
       current_in_ptr += N;
       current_out_ptr += N;
       s -= N;
     }
-    T normalizer = ops.reduce_add(vnormalizer);
+    AccT normalizer = ops.reduce_add(vnormalizer);
     while (s-- > 0) {
-      T _exp = std::exp(*current_in_ptr - maximum);
-      *current_out_ptr = _exp;
+      AccT _exp = std::exp(*current_in_ptr - maximum);
+      if (std::is_same<T, AccT>::value) {
+        *current_out_ptr = _exp;
+      }
       normalizer += _exp;
       current_in_ptr++;
       current_out_ptr++;
@@ -254,14 +279,33 @@ void softmax(const array& in, array& out) {
 
     // Normalize
     current_out_ptr = out_ptr;
+    current_in_ptr = in_ptr;
     s = M;
     while (s >= N) {
-      ops.store(current_out_ptr, ops.mul(*(VT*)current_out_ptr, normalizer));
+      if constexpr (std::is_same<T, AccT>::value) {
+        ops.store(current_out_ptr, ops.mul(*(VT*)current_out_ptr, normalizer));
+      } else {
+        VT vexp;
+        for (int i = 0; i < N; ++i) {
+          vexp[i] = static_cast<AccT>(current_in_ptr[i]);
+        }
+        vexp = ops.mul(ops.exp(ops.sub(vexp, maximum)), normalizer);
+        for (int i = 0; i < N; ++i) {
+          current_out_ptr[i] = vexp[i];
+        }
+        current_in_ptr += N;
+      }
       current_out_ptr += N;
       s -= N;
     }
     while (s-- > 0) {
-      *current_out_ptr *= normalizer;
+      if constexpr (std::is_same<T, AccT>::value) {
+        *current_out_ptr *= normalizer;
+      } else {
+        AccT _exp = std::exp(*current_in_ptr - maximum);
+        *current_out_ptr = static_cast<T>(_exp * normalizer);
+        current_in_ptr++;
+      }
       current_out_ptr++;
     }
   }
@@ -274,7 +318,12 @@ void Softmax::eval_cpu(const std::vector<array>& inputs, array& out) {
 
   // Make sure that the last dimension is contiguous
   auto check_input = [](array x) {
-    if (x.strides()[x.ndim() - 1] == 1) {
+    bool no_copy = x.strides()[x.ndim() - 1] == 1;
+    if (x.ndim() > 1) {
+      auto s = x.strides()[x.ndim() - 2];
+      no_copy &= (s == 0 || s == x.shape().back());
+    }
+    if (no_copy) {
       return x;
     } else {
       array x_copy(x.shape(), x.dtype(), nullptr, {});
@@ -303,15 +352,33 @@ void Softmax::eval_cpu(const std::vector<array>& inputs, array& out) {
           "Softmax is defined only for floating point types");
       break;
     case float32:
-      softmax<float, simd_float16, AccelerateSimdOps<float, simd_float16>, 16>(
-          in, out);
+      softmax<
+          float,
+          float,
+          simd_float16,
+          AccelerateSimdOps<float, simd_float16>,
+          16>(in, out);
       break;
     case float16:
-      softmax<
-          float16_t,
-          float16x8_t,
-          NeonFp16SimdOps<float16_t, float16x8_t>,
-          8>(in, out);
+      if (precise_) {
+        softmax<
+            float16_t,
+            float,
+            simd_float16,
+            AccelerateSimdOps<float, simd_float16>,
+            16>(in, out);
+      } else {
+#if __ARM_FEATURE_FP16_VECTOR_ARITHMETIC
+        softmax<
+            float16_t,
+            float16_t,
+            float16x8_t,
+            NeonFp16SimdOps<float16_t, float16x8_t>,
+            8>(in, out);
+#else // __ARM_FEATURE_FP16_VECTOR_ARITHMETIC
+        eval(inputs, out); // Redirect to common backend for consistency
+#endif // __ARM_FEATURE_FP16_VECTOR_ARITHMETIC
+      }
       break;
     case bfloat16:
       eval(inputs, out);

mlx/backend/accelerate/utils.h

@@ -1,8 +1,8 @@
-// Copyright © 2023 Apple Inc.
+// Copyright © 2023-2024 Apple Inc.
 
 #pragma once
 
-#include <vecLib/BNNS/bnns.h>
+#include <Accelerate/Accelerate.h>
 #include "mlx/dtype.h"
 
 namespace mlx::core {

mlx/backend/common/CMakeLists.txt

@@ -1,20 +1,78 @@
+
+if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+  set(COMPILER ${CMAKE_C_COMPILER})
+  set(CLANG TRUE)
+else()
+  set(COMPILER ${CMAKE_CXX_COMPILER})
+endif()
+
+add_custom_command(
+    OUTPUT  compiled_preamble.cpp
+    COMMAND /bin/bash
+              ${CMAKE_CURRENT_SOURCE_DIR}/make_compiled_preamble.sh
+              ${CMAKE_CURRENT_BINARY_DIR}/compiled_preamble.cpp
+              ${COMPILER}
+              ${PROJECT_SOURCE_DIR}
+              ${CLANG}
+
+    DEPENDS make_compiled_preamble.sh
+            compiled_preamble.h
+            ${PROJECT_SOURCE_DIR}/mlx/types/half_types.h
+            ${PROJECT_SOURCE_DIR}/mlx/types/fp16.h
+            ${PROJECT_SOURCE_DIR}/mlx/types/bf16.h
+            ${PROJECT_SOURCE_DIR}/mlx/types/complex.h
+            ops.h
+)
+
+add_custom_target(
+  cpu_compiled_preamble
+  DEPENDS compiled_preamble.cpp
+)
+
+add_dependencies(mlx cpu_compiled_preamble)
+
 target_sources(
   mlx
   PRIVATE
   ${CMAKE_CURRENT_SOURCE_DIR}/arg_reduce.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/binary.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/compiled.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/common.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/conv.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/copy.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/erf.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/fft.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/hadamard.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/masked_mm.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/primitives.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/quantized.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/reduce.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/reduce_utils.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/scan.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/select.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/slicing.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/softmax.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/sort.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/threefry.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/indexing.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/load.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/qrf.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/svd.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/inverse.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/cholesky.cpp
+  ${CMAKE_CURRENT_BINARY_DIR}/compiled_preamble.cpp
 )
+
+if (IOS)
+  target_sources(
+    mlx
+    PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/compiled_nocpu.cpp
+  )
+else()
+  target_sources(
+    mlx
+    PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/compiled_cpu.cpp
+  )
+endif()

mlx/backend/common/binary.cpp

@@ -7,6 +7,7 @@
 #include "mlx/allocator.h"
 #include "mlx/backend/common/binary.h"
 #include "mlx/backend/common/binary_two.h"
+#include "mlx/backend/common/ops.h"
 #include "mlx/primitives.h"
 #include "mlx/utils.h"
 
@@ -73,7 +74,7 @@ void Add::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   auto& a = inputs[0];
   auto& b = inputs[1];
-  binary(a, b, out, [](auto x, auto y) { return x + y; });
+  binary(a, b, out, detail::Add());
 }
 
 void DivMod::eval(
@@ -135,93 +136,59 @@ void Divide::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   auto& a = inputs[0];
   auto& b = inputs[1];
-  binary(a, b, out, [](auto x, auto y) { return x / y; });
+  binary(a, b, out, detail::Divide());
 }
 
-struct RemainderFn {
-  template <typename T>
-  std::enable_if_t<!std::is_integral_v<T>, T> operator()(
-      T numerator,
-      T denominator) {
-    return std::fmod(numerator, denominator);
-  }
-
-  template <typename T>
-  std::enable_if_t<std::is_integral_v<T>, T> operator()(
-      T numerator,
-      T denominator) {
-    return numerator % denominator;
-  }
-};
-
 void Remainder::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   auto& a = inputs[0];
   auto& b = inputs[1];
-  binary(a, b, out, RemainderFn{});
+  binary(a, b, out, detail::Remainder());
 }
 
 void Equal::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   if (equal_nan_) {
-    comparison_op(inputs[0], inputs[1], out, [](auto x, auto y) {
-      return x == y || (std::isnan(x) && std::isnan(y));
-    });
+    comparison_op(inputs[0], inputs[1], out, detail::NaNEqual());
   } else {
-    comparison_op(
-        inputs[0], inputs[1], out, [](auto x, auto y) { return x == y; });
+    comparison_op(inputs[0], inputs[1], out, detail::Equal());
   }
 }
 
 void Greater::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
-  comparison_op(
-      inputs[0], inputs[1], out, [](auto x, auto y) { return x > y; });
+  comparison_op(inputs[0], inputs[1], out, detail::Greater());
 }
 
 void GreaterEqual::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
-  comparison_op(
-      inputs[0], inputs[1], out, [](auto x, auto y) { return x >= y; });
+  comparison_op(inputs[0], inputs[1], out, detail::GreaterEqual());
 }
 
 void Less::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
-  comparison_op(
-      inputs[0], inputs[1], out, [](auto x, auto y) { return x < y; });
+  comparison_op(inputs[0], inputs[1], out, detail::Less());
 }
 
 void LessEqual::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
-  comparison_op(
-      inputs[0], inputs[1], out, [](auto x, auto y) { return x <= y; });
+  comparison_op(inputs[0], inputs[1], out, detail::LessEqual());
 }
 
 void LogAddExp::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   auto& a = inputs[0];
   auto& b = inputs[1];
-  auto op = [](auto x, auto y) {
-    constexpr float inf = std::numeric_limits<float>::infinity();
-    auto maxval = (x > y) ? x : y;
-    auto minval = (x > y) ? y : x;
-    return (minval == -inf || maxval == inf)
-        ? maxval
-        : static_cast<decltype(x)>(
-              maxval + std::log1p(std::exp(minval - maxval)));
-  };
-  if (is_floating_point(out.dtype())) {
-    if (out.dtype() == float32) {
-      binary_op<float>(a, b, out, op);
-    } else if (out.dtype() == float16) {
-      binary_op<float16_t>(a, b, out, op);
-    } else if (out.dtype() == bfloat16) {
-      binary_op<bfloat16_t>(a, b, out, op);
-    } else {
-      std::ostringstream err;
-      err << "[logaddexp] Does not support " << out.dtype();
-      throw std::invalid_argument(err.str());
-    }
+  if (out.dtype() == float32) {
+    binary_op<float>(a, b, out, detail::LogAddExp());
+  } else if (out.dtype() == float16) {
+    binary_op<float16_t>(a, b, out, detail::LogAddExp());
+  } else if (out.dtype() == bfloat16) {
+    binary_op<bfloat16_t>(a, b, out, detail::LogAddExp());
+  } else if (issubdtype(out.dtype(), inexact)) {
+    std::ostringstream err;
+    err << "[logaddexp] Does not support " << out.dtype();
+    throw std::invalid_argument(err.str());
   } else {
     throw std::invalid_argument(
         "[logaddexp] Cannot compute logaddexp for arrays with"
@@ -229,88 +196,136 @@ void LogAddExp::eval(const std::vector<array>& inputs, array& out) {
   }
 }
 
+void LogicalAnd::eval(const std::vector<array>& inputs, array& out) {
+  assert(inputs.size() == 2); // LogicalAnd requires two input arrays
+  auto& in1 = inputs[0];
+  auto& in2 = inputs[1];
+  binary(in1, in2, out, detail::LogicalAnd());
+}
+
+void LogicalOr::eval(const std::vector<array>& inputs, array& out) {
+  assert(inputs.size() == 2); // LogicalOr requires two input arrays
+  auto& in1 = inputs[0];
+  auto& in2 = inputs[1];
+  binary(in1, in2, out, detail::LogicalOr());
+}
+
 void Maximum::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   auto& a = inputs[0];
   auto& b = inputs[1];
-
-  if (is_floating_point(out.dtype())) {
-    binary(a, b, out, [](auto x, auto y) {
-      if (std::isnan(x)) {
-        return x;
-      }
-      return (x > y) ? x : y;
-    });
-  } else {
-    binary(a, b, out, [](auto x, auto y) { return (x > y) ? x : y; });
-  }
+  binary(a, b, out, detail::Maximum());
 }
 
 void Minimum::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   auto& a = inputs[0];
   auto& b = inputs[1];
-  if (is_floating_point(out.dtype())) {
-    binary(a, b, out, [](auto x, auto y) {
-      if (std::isnan(x)) {
-        return x;
-      }
-      return (x < y) ? x : y;
-    });
-  } else {
-    binary(a, b, out, [](auto x, auto y) { return (x < y) ? x : y; });
-  }
+  binary(a, b, out, detail::Minimum());
 }
 
 void Multiply::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   auto& a = inputs[0];
   auto& b = inputs[1];
-  binary(a, b, out, [](auto x, auto y) { return x * y; });
+  binary(a, b, out, detail::Multiply());
 }
 
 void NotEqual::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
-  comparison_op(
-      inputs[0], inputs[1], out, [](auto x, auto y) { return x != y; });
+  comparison_op(inputs[0], inputs[1], out, detail::NotEqual());
 }
 
-struct PowerFn {
-  template <typename T>
-  std::enable_if_t<!std::is_integral_v<T>, T> operator()(T base, T exp) {
-    return std::pow(base, exp);
-  }
-
-  template <typename T>
-  std::enable_if_t<std::is_integral_v<T>, T> operator()(T base, T exp) {
-    if (exp < 0) {
-      throw std::invalid_argument(
-          "Integers cannot be raise to negative powers");
-    }
-    T res = 1;
-    while (exp) {
-      if (exp & 1) {
-        res *= base;
-      }
-      exp >>= 1;
-      base *= base;
-    }
-    return res;
-  }
-};
-
 void Power::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   auto& a = inputs[0];
   auto& b = inputs[1];
-  binary(a, b, out, PowerFn{});
+  binary(a, b, out, detail::Power());
 }
 
 void Subtract::eval(const std::vector<array>& inputs, array& out) {
   assert(inputs.size() == 2);
   auto& a = inputs[0];
   auto& b = inputs[1];
-  binary(a, b, out, [](auto x, auto y) { return x - y; });
+  binary(a, b, out, detail::Subtract());
+}
+
+void BitwiseBinary::eval_cpu(const std::vector<array>& inputs, array& out) {
+  assert(inputs.size() == 2);
+  auto& a = inputs[0];
+  auto& b = inputs[1];
+  auto dispatch_type = [&a, &b, &out](auto op) {
+    switch (out.dtype()) {
+      case bool_:
+        binary_op<bool>(a, b, out, op);
+      case uint8:
+        binary_op<uint8_t>(a, b, out, op);
+        break;
+      case uint16:
+        binary_op<uint16_t>(a, b, out, op);
+        break;
+      case uint32:
+        binary_op<uint32_t>(a, b, out, op);
+        break;
+      case uint64:
+        binary_op<uint64_t>(a, b, out, op);
+        break;
+      case int8:
+        binary_op<int8_t>(a, b, out, op);
+        break;
+      case int16:
+        binary_op<int16_t>(a, b, out, op);
+        break;
+      case int32:
+        binary_op<int32_t>(a, b, out, op);
+        break;
+      case int64:
+        binary_op<int64_t>(a, b, out, op);
+        break;
+      default:
+        throw std::runtime_error(
+            "[BitwiseBinary::eval_cpu] Type not supported");
+        break;
+    }
+  };
+  switch (op_) {
+    case BitwiseBinary::And:
+      dispatch_type(detail::BitwiseAnd());
+      break;
+    case BitwiseBinary::Or:
+      dispatch_type(detail::BitwiseOr());
+      break;
+    case BitwiseBinary::Xor:
+      dispatch_type(detail::BitwiseXor());
+      break;
+    case BitwiseBinary::LeftShift:
+      dispatch_type(detail::LeftShift());
+      break;
+    case BitwiseBinary::RightShift:
+      dispatch_type(detail::RightShift());
+      break;
+  }
+}
+
+void ArcTan2::eval(const std::vector<array>& inputs, array& out) {
+  assert(inputs.size() == 2);
+  const auto& a = inputs[0];
+  const auto& b = inputs[1];
+  if (out.dtype() == float32) {
+    binary_op<float>(a, b, out, detail::ArcTan2());
+  } else if (out.dtype() == float16) {
+    binary_op<float16_t>(a, b, out, detail::ArcTan2());
+  } else if (out.dtype() == bfloat16) {
+    binary_op<bfloat16_t>(a, b, out, detail::ArcTan2());
+  } else if (issubdtype(out.dtype(), inexact)) {
+    std::ostringstream err;
+    err << "[arctan2] Does not support " << out.dtype();
+    throw std::invalid_argument(err.str());
+  } else {
+    throw std::invalid_argument(
+        "[arctan2] Cannot compute inverse tangent for arrays"
+        " with non floating point type.");
+  }
 }
 
 } // namespace mlx::core

mlx/backend/common/binary.h

@@ -1,6 +1,8 @@
 // Copyright © 2023 Apple Inc.
 
 #pragma once
+#include <cassert>
+
 #include "mlx/allocator.h"
 #include "mlx/array.h"
 #include "mlx/backend/common/utils.h"
@@ -9,7 +11,7 @@ namespace mlx::core {
 
 namespace {
 
-enum BinaryOpType {
+enum class BinaryOpType {
   ScalarScalar,
   ScalarVector,
   VectorScalar,
@@ -20,17 +22,17 @@ enum BinaryOpType {
 BinaryOpType get_binary_op_type(const array& a, const array& b) {
   BinaryOpType bopt;
   if (a.data_size() == 1 && b.data_size() == 1) {
-    bopt = ScalarScalar;
+    bopt = BinaryOpType::ScalarScalar;
   } else if (a.data_size() == 1 && b.flags().contiguous) {
-    bopt = ScalarVector;
+    bopt = BinaryOpType::ScalarVector;
   } else if (b.data_size() == 1 && a.flags().contiguous) {
-    bopt = VectorScalar;
+    bopt = BinaryOpType::VectorScalar;
   } else if (
       a.flags().row_contiguous && b.flags().row_contiguous ||
       a.flags().col_contiguous && b.flags().col_contiguous) {
-    bopt = VectorVector;
+    bopt = BinaryOpType::VectorVector;
   } else {
-    bopt = General;
+    bopt = BinaryOpType::General;
   }
   return bopt;
 }
@@ -42,11 +44,11 @@ void set_binary_op_output_data(
     BinaryOpType bopt,
     bool donate_with_move = false) {
   switch (bopt) {
-    case ScalarScalar:
+    case BinaryOpType::ScalarScalar:
       out.set_data(
           allocator::malloc_or_wait(out.itemsize()), 1, a.strides(), a.flags());
       break;
-    case ScalarVector:
+    case BinaryOpType::ScalarVector:
       if (b.is_donatable() && b.itemsize() == out.itemsize()) {
         if (donate_with_move) {
           out.move_shared_buffer(b);
@@ -61,7 +63,7 @@ void set_binary_op_output_data(
             b.flags());
       }
       break;
-    case VectorScalar:
+    case BinaryOpType::VectorScalar:
       if (a.is_donatable() && a.itemsize() == out.itemsize()) {
         if (donate_with_move) {
           out.move_shared_buffer(a);
@@ -76,7 +78,7 @@ void set_binary_op_output_data(
             a.flags());
       }
       break;
-    case VectorVector:
+    case BinaryOpType::VectorVector:
       if (a.is_donatable() && a.itemsize() == out.itemsize()) {
         if (donate_with_move) {
           out.move_shared_buffer(a);
@@ -97,7 +99,7 @@ void set_binary_op_output_data(
             a.flags());
       }
       break;
-    case General:
+    case BinaryOpType::General:
       if (a.is_donatable() && a.flags().row_contiguous &&
           a.itemsize() == out.itemsize() && a.size() == out.size()) {
         if (donate_with_move) {
@@ -424,25 +426,25 @@ void binary_op(
   set_binary_op_output_data(a, b, out, bopt);
 
   // The full computation is scalar scalar so call the base op once
-  if (bopt == ScalarScalar) {
+  if (bopt == BinaryOpType::ScalarScalar) {
     *(out.data<U>()) = op(*a.data<T>(), *b.data<T>());
     return;
   }
 
   // The full computation is scalar vector so delegate to the op
-  if (bopt == ScalarVector) {
+  if (bopt == BinaryOpType::ScalarVector) {
     opsv(a.data<T>(), b.data<T>(), out.data<U>(), b.data_size());
     return;
   }
 
   // The full computation is vector scalar so delegate to the op
-  if (bopt == VectorScalar) {
+  if (bopt == BinaryOpType::VectorScalar) {
     opvs(a.data<T>(), b.data<T>(), out.data<U>(), a.data_size());
     return;
   }
 
   // The full computation is vector vector so delegate to the op
-  if (bopt == VectorVector) {
+  if (bopt == BinaryOpType::VectorVector) {
     opvv(a.data<T>(), b.data<T>(), out.data<U>(), out.size());
     return;
   }
@@ -475,17 +477,17 @@ void binary_op(
   // Case 1: LxM and FxM where L and F are broadcastable and M is row contiguous
   int dim = ndim;
   if (int d = std::max(a_rc_dim, b_rc_dim); d < ndim) {
-    bopt = VectorVector;
+    bopt = BinaryOpType::VectorVector;
     dim = d;
     // Case 2: LxM and Fx1 where L and F are broadcastable and M is row
     // contiguous
   } else if (int d = std::max(a_rc_dim, b_s_dim); d < ndim) {
-    bopt = VectorScalar;
+    bopt = BinaryOpType::VectorScalar;
     dim = d;
     // Case 3: Lx1 and FxM where L and F are broadcastable and M is row
     // contiguous
   } else if (int d = std::max(a_s_dim, b_rc_dim); d < ndim) {
-    bopt = ScalarVector;
+    bopt = BinaryOpType::ScalarVector;
     dim = d;
   }
 
@@ -495,20 +497,20 @@ void binary_op(
   size_t stride;
   if (dim == 0 || strides[dim - 1] < 16) {
     stride = 1;
-    bopt = General;
+    bopt = BinaryOpType::General;
     dim = ndim;
   } else {
     stride = strides[dim - 1];
   }
 
   switch (bopt) {
-    case VectorVector:
+    case BinaryOpType::VectorVector:
       binary_op_dispatch_dims<T, U>(a, b, out, opvv, dim, stride);
       break;
-    case VectorScalar:
+    case BinaryOpType::VectorScalar:
       binary_op_dispatch_dims<T, U>(a, b, out, opvs, dim, stride);
       break;
-    case ScalarVector:
+    case BinaryOpType::ScalarVector:
       binary_op_dispatch_dims<T, U>(a, b, out, opsv, dim, stride);
       break;
     default:

mlx/backend/common/binary_two.h

@@ -260,14 +260,14 @@ void binary_op(
   set_binary_op_output_data(a, b, out_b, bopt);
 
   // The full computation is scalar scalar so call the base op once
-  if (bopt == ScalarScalar) {
+  if (bopt == BinaryOpType::ScalarScalar) {
     std::tie(*(out_a.data<U>()), *(out_b.data<U>())) =
         op(*a.data<T>(), *b.data<T>());
     return;
   }
 
   // The full computation is scalar vector so delegate to the op
-  if (bopt == ScalarVector) {
+  if (bopt == BinaryOpType::ScalarVector) {
     opsv(
         a.data<T>(),
         b.data<T>(),
@@ -278,7 +278,7 @@ void binary_op(
   }
 
   // The full computation is vector scalar so delegate to the op
-  if (bopt == VectorScalar) {
+  if (bopt == BinaryOpType::VectorScalar) {
     opvs(
         a.data<T>(),
         b.data<T>(),
@@ -289,7 +289,7 @@ void binary_op(
   }
 
   // The full computation is vector vector so delegate to the op
-  if (bopt == VectorVector) {
+  if (bopt == BinaryOpType::VectorVector) {
     opvv(
         a.data<T>(),
         b.data<T>(),
@@ -327,17 +327,17 @@ void binary_op(
   // Case 1: LxM and FxM where L and F are broadcastable and M is row contiguous
   int dim = ndim;
   if (int d = std::max(a_rc_dim, b_rc_dim); d < ndim) {
-    bopt = VectorVector;
+    bopt = BinaryOpType::VectorVector;
     dim = d;
     // Case 2: LxM and Fx1 where L and F are broadcastable and M is row
     // contiguous
   } else if (int d = std::max(a_rc_dim, b_s_dim); d < ndim) {
-    bopt = VectorScalar;
+    bopt = BinaryOpType::VectorScalar;
     dim = d;
     // Case 3: Lx1 and FxM where L and F are broadcastable and M is row
     // contiguous
   } else if (int d = std::max(a_s_dim, b_rc_dim); d < ndim) {
-    bopt = ScalarVector;
+    bopt = BinaryOpType::ScalarVector;
     dim = d;
   }
 
@@ -347,20 +347,20 @@ void binary_op(
   size_t stride;
   if (dim == 0 || strides[dim - 1] < 16) {
     stride = 1;
-    bopt = General;
+    bopt = BinaryOpType::General;
     dim = ndim;
   } else {
     stride = strides[dim - 1];
   }
 
   switch (bopt) {
-    case VectorVector:
+    case BinaryOpType::VectorVector:
       binary_op_dispatch_dims<T, U>(a, b, out_a, out_b, opvv, dim, stride);
       break;
-    case VectorScalar:
+    case BinaryOpType::VectorScalar:
       binary_op_dispatch_dims<T, U>(a, b, out_a, out_b, opvs, dim, stride);
       break;
-    case ScalarVector:
+    case BinaryOpType::ScalarVector:
       binary_op_dispatch_dims<T, U>(a, b, out_a, out_b, opsv, dim, stride);
       break;
     default:

mlx/backend/common/cholesky.cpp

@@ -0,0 +1,101 @@
+// Copyright © 2023-2024 Apple Inc.
+
+#include "mlx/allocator.h"
+#include "mlx/backend/common/copy.h"
+#include "mlx/linalg.h"
+#include "mlx/primitives.h"
+
+#ifdef ACCELERATE_NEW_LAPACK
+#include <Accelerate/Accelerate.h>
+#else
+#include <lapack.h>
+#endif
+
+namespace mlx::core {
+
+namespace {
+
+// Delegate to the Cholesky factorization taking into account differences in
+// LAPACK implementations (basically how to pass the 'uplo' string to fortran).
+int spotrf_wrapper(char uplo, float* matrix, int N) {
+  int info;
+
+#ifdef LAPACK_FORTRAN_STRLEN_END
+  spotrf_(
+      /* uplo = */ &uplo,
+      /* n = */ &N,
+      /* a = */ matrix,
+      /* lda = */ &N,
+      /* info = */ &info,
+      /* uplo_len = */ static_cast<size_t>(1));
+#else
+  spotrf_(
+      /* uplo = */ &uplo,
+      /* n = */ &N,
+      /* a = */ matrix,
+      /* lda = */ &N,
+      /* info = */ &info);
+#endif
+
+  return info;
+}
+
+} // namespace
+
+void cholesky_impl(const array& a, array& factor, bool upper) {
+  // Lapack uses the column-major convention. We take advantage of the fact that
+  // the matrix should be symmetric:
+  //   (A)ᵀ = A
+  // and that a column-major lower triangular matrix is a row-major upper
+  // triangular matrix, so uplo is the opposite of what we would expect from
+  // upper
+
+  char uplo = (upper) ? 'L' : 'U';
+
+  // The decomposition is computed in place, so just copy the input to the
+  // output.
+  copy(
+      a,
+      factor,
+      a.flags().row_contiguous ? CopyType::Vector : CopyType::General);
+
+  const int N = a.shape(-1);
+  const size_t num_matrices = a.size() / (N * N);
+
+  float* matrix = factor.data<float>();
+
+  for (int i = 0; i < num_matrices; i++) {
+    // Compute Cholesky factorization.
+    int info = spotrf_wrapper(uplo, matrix, N);
+
+    // TODO: We do nothing when the matrix is not positive semi-definite
+    // because throwing an error would result in a crash. If we figure out how
+    // to catch errors from the implementation we should throw.
+    if (info < 0) {
+      std::stringstream msg;
+      msg << "[cholesky] Cholesky decomposition failed with error code "
+          << info;
+      throw std::runtime_error(msg.str());
+    }
+
+    // Zero out the upper/lower triangle while advancing the pointer to the
+    // next matrix at the same time.
+    for (int row = 0; row < N; row++) {
+      if (upper) {
+        std::fill(matrix, matrix + row, 0);
+      } else {
+        std::fill(matrix + row + 1, matrix + N, 0);
+      }
+      matrix += N;
+    }
+  }
+}
+
+void Cholesky::eval(const std::vector<array>& inputs, array& output) {
+  if (inputs[0].dtype() != float32) {
+    throw std::runtime_error("[Cholesky::eval] only supports float32.");
+  }
+  cholesky_impl(inputs[0], output, upper_);
+}
+
+} // namespace mlx::core