mlx/mlx/backend/metal/slicing.cpp
Awni Hannun 6bd28d246e
Allow no copy negative strides in as_strided and slice (#1688)
* allow no copy negative strides in as_strided and slice

* fix jit

* fix jit
2024-12-12 08:59:45 -08:00

89 lines
2.5 KiB
C++

// Copyright © 2024 Apple Inc.
#include <numeric>
#include "mlx/backend/common/slicing.h"
#include "mlx/backend/metal/copy.h"
#include "mlx/backend/metal/device.h"
namespace mlx::core {
void slice_gpu(
const array& in,
array& out,
const Shape& start_indices,
const Shape& strides,
const Stream& s) {
// Calculate out strides, initial offset and if copy needs to be made
auto [data_offset, inp_strides] = prepare_slice(in, start_indices, strides);
size_t data_end = 1;
for (int i = 0; i < strides.size(); ++i) {
if (in.shape()[i] > 1) {
auto end_idx = start_indices[i] + out.shape()[i] * strides[i] - 1;
data_end += end_idx * in.strides()[i];
}
}
size_t data_size = data_end - data_offset;
shared_buffer_slice(in, inp_strides, data_offset, data_size, out);
}
void concatenate_gpu(
const std::vector<array>& inputs,
array& out,
int axis,
const Stream& s) {
std::vector<int> sizes;
sizes.push_back(0);
for (auto& p : inputs) {
sizes.push_back(p.shape(axis));
}
std::partial_sum(sizes.cbegin(), sizes.cend(), sizes.begin());
out.set_data(allocator::malloc_or_wait(out.nbytes()));
auto strides = out.strides();
auto flags = out.flags();
flags.row_contiguous = false;
flags.col_contiguous = false;
flags.contiguous = false;
auto& d = metal::device(s.device);
auto& compute_encoder = d.get_command_encoder(s.index);
auto concurrent_ctx = compute_encoder.start_concurrent();
for (int i = 0; i < inputs.size(); i++) {
array out_slice(inputs[i].shape(), out.dtype(), nullptr, {});
size_t data_offset = strides[axis] * sizes[i];
out_slice.copy_shared_buffer(
out, strides, flags, out_slice.size(), data_offset);
copy_gpu_inplace(inputs[i], out_slice, CopyType::GeneralGeneral, s);
}
}
void pad_gpu(
const array& in,
const array& val,
array& out,
std::vector<int> axes,
std::vector<int> low_pad_size,
const Stream& s) {
// Fill output with val
fill_gpu(val, out, s);
// Find offset for start of input values
size_t data_offset = 0;
for (int i = 0; i < axes.size(); i++) {
auto ax = axes[i] < 0 ? out.ndim() + axes[i] : axes[i];
data_offset += out.strides()[ax] * low_pad_size[i];
}
// Extract slice from output where input will be pasted
array out_slice(in.shape(), out.dtype(), nullptr, {});
out_slice.copy_shared_buffer(
out, out.strides(), out.flags(), out_slice.size(), data_offset);
// Copy input values into the slice
copy_gpu_inplace(in, out_slice, CopyType::GeneralGeneral, s);
}
} // namespace mlx::core