Fix divide types + floor divide (//) (#138)

* divide types

* fix black + test

python/mlx/nn/layers/activations.py

@@ -176,6 +176,8 @@ def selu(x):
     See also :func:`elu`.
     """
     return elu(x, 1.67326) * 1.0507
+
+
 def prelu(x: mx.array, alpha: mx.array) -> mx.array:
     r"""Applies the element-wise function:
 

python/src/array.cpp

@@ -623,25 +623,41 @@ void init_array(py::module_& m) {
       .def(
           "__truediv__",
           [](const array& a, const ScalarOrArray v) {
-            return divide(a, to_array(v, float32));
+            return divide(a, to_array(v, a.dtype()));
           },
           "other"_a)
       .def(
           "__div__",
           [](const array& a, const ScalarOrArray v) {
-            return divide(a, to_array(v, float32));
+            return divide(a, to_array(v, a.dtype()));
+          },
+          "other"_a)
+      .def(
+          "__floordiv__",
+          [](const array& a, const ScalarOrArray v) {
+            auto b = to_array(v, a.dtype());
+            auto t = promote_types(a.dtype(), b.dtype());
+            return astype(divide(a, b), t);
           },
           "other"_a)
       .def(
           "__rtruediv__",
           [](const array& a, const ScalarOrArray v) {
-            return divide(to_array(v, float32), a);
+            return divide(to_array(v, a.dtype()), a);
+          },
+          "other"_a)
+      .def(
+          "__rfloordiv__",
+          [](const array& a, const ScalarOrArray v) {
+            auto b = to_array(v, a.dtype());
+            auto t = promote_types(a.dtype(), b.dtype());
+            return astype(divide(b, a), t);
           },
           "other"_a)
       .def(
           "__rdiv__",
           [](const array& a, const ScalarOrArray v) {
-            return divide(to_array(v, float32), a);
+            return divide(to_array(v, a.dtype()), a);
           },
           "other"_a)
       .def(

python/tests/mlx_tests.py

@@ -2,7 +2,7 @@
 
 import os
 import unittest
-from typing import Callable, List, Tuple
+from typing import Callable, List, Tuple, Union
 
 import mlx.core as mx
 import numpy as np
@@ -21,7 +21,7 @@ class MLXTestCase(unittest.TestCase):
 
     def assertEqualArray(
         self,
-        args: List[mx.array | float | int],
+        args: List[Union[mx.array, float, int]],
         mlx_func: Callable[..., mx.array],
         expected: mx.array,
         atol=1e-2,

python/tests/test_ops.py

@@ -236,6 +236,24 @@ class TestOps(mlx_tests.MLXTestCase):
         self.assertEqual(z.dtype, mx.float32)
         self.assertEqual(z.item(), 0.5)
 
+        x = x.astype(mx.float16)
+        z = x / 4.0
+        self.assertEqual(z.dtype, mx.float16)
+
+        x = x.astype(mx.float16)
+        z = 4.0 / x
+        self.assertEqual(z.dtype, mx.float16)
+
+        x = mx.array(5)
+        y = mx.array(2)
+        z = x / y
+        self.assertEqual(z.dtype, mx.float32)
+        self.assertEqual(z.item(), 2.5)
+
+        z = x // y
+        self.assertEqual(z.dtype, mx.int32)
+        self.assertEqual(z.item(), 2)
+
     def test_remainder(self):
         for dt in [mx.int32, mx.float32]:
             x = mx.array(2, dtype=dt)