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paddlepaddle--paddle/paddle/phi/kernels/gpu/index_select_grad_kernel.cu
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// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// 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.
#include "paddle/phi/kernels/index_select_grad_kernel.h"
#include "glog/logging.h"
#include "paddle/common/enforce.h"
#include "paddle/common/flags.h"
#include "paddle/phi/backends/gpu/gpu_info.h"
#include "paddle/phi/backends/gpu/gpu_launch_config.h"
#include "paddle/phi/backends/gpu/gpu_primitives.h"
#include "paddle/phi/core/kernel_registry.h"
#include "paddle/phi/core/utils/data_type.h"
#include "paddle/phi/kernels/full_kernel.h"
#include "paddle/phi/kernels/funcs/math_function.h"
COMMON_DECLARE_bool(cudnn_deterministic);
namespace phi {
template <typename T, typename IndexT>
__global__ void index_select_grad_cuda_kernel(const T* output_grad,
T* input_grad,
const IndexT* index,
int64_t N,
int64_t stride,
int64_t size,
int64_t delta,
int64_t dim_size) {
CUDA_KERNEL_LOOP_TYPE(idx, N, int64_t) {
int64_t pre_idx = idx / (stride * size);
int64_t dim_idx = idx % (stride * size) / stride;
IndexT src_dim_idx = index[dim_idx];
if (src_dim_idx < 0) {
src_dim_idx += dim_size;
}
int64_t input_idx =
idx + (delta * pre_idx + src_dim_idx - dim_idx) * stride;
CudaAtomicAdd(&input_grad[input_idx], output_grad[idx]);
}
}
template <typename T, typename IndexT>
__global__ void index_select_grad_deterministic_cuda_kernel(
const T* output_grad,
T* input_grad,
const IndexT* index,
int64_t index_size,
int64_t stride,
int64_t pre_size,
int64_t input_dim_size) {
int64_t num_columns = pre_size * stride;
CUDA_KERNEL_LOOP_TYPE(col_idx, num_columns, int64_t) {
int64_t pre_idx = col_idx / stride;
int64_t post_idx = col_idx % stride;
for (int64_t k = 0; k < index_size; ++k) {
IndexT src_dim_idx = index[k];
if (src_dim_idx < 0) {
src_dim_idx += input_dim_size;
}
int64_t out_grad_idx = (pre_idx * index_size + k) * stride + post_idx;
int64_t in_grad_idx =
(pre_idx * input_dim_size + src_dim_idx) * stride + post_idx;
input_grad[in_grad_idx] += output_grad[out_grad_idx];
}
}
}
template <typename T, typename Context>
void IndexSelectGradKernel(const Context& dev_ctx,
const DenseTensor& x,
const DenseTensor& index,
const DenseTensor& out_grad,
int dim,
DenseTensor* x_grad) {
if (out_grad.numel() == 0) {
Full<T, Context>(dev_ctx, x.dims(), 0, x_grad);
return;
}
auto* output_grad_data = out_grad.data<T>();
auto* in_grad_data = dev_ctx.template Alloc<T>(x_grad);
auto input_dim = x_grad->dims();
auto output_dim = out_grad.dims();
dim = dim >= 0 ? dim : dim + input_dim.size();
auto stride_dim = common::stride(input_dim);
int64_t stride = stride_dim[dim];
int64_t size = output_dim[dim];
int64_t delta = input_dim[dim] - size;
const auto& index_type = index.dtype();
bool index_type_match =
index_type == DataType::INT64 || index_type == DataType::INT32;
PADDLE_ENFORCE_EQ(index_type_match,
true,
common::errors::InvalidArgument(
"Input(Index) holds the wrong type, it holds %s, but "
"desires to be %s or %s",
index_type,
DataType::INT32,
DataType::INT64));
int64_t numel = x_grad->numel();
if (numel == 0) {
return;
}
int64_t out_nums = out_grad.numel();
auto stream = dev_ctx.stream();
funcs::SetConstant<GPUContext, T> index_select_grad_init;
index_select_grad_init(dev_ctx, x_grad, static_cast<T>(0));
if (FLAGS_cudnn_deterministic) {
int64_t pre_size = out_nums / (size * stride);
int64_t num_columns = pre_size * stride;
unsigned int block_dim = PADDLE_CUDA_NUM_THREADS;
const uint64_t grid_x = (num_columns + block_dim - 1) / block_dim;
PADDLE_ENFORCE_LE_UINT32_MAX(grid_x, "grid.x");
dim3 grid_dim = dim3(static_cast<uint32_t>(grid_x));
backends::gpu::LimitGridDim(dev_ctx, &grid_dim);
if (index_type == DataType::INT64) {
const int64_t* index_data = index.data<int64_t>();
index_select_grad_deterministic_cuda_kernel<T, int64_t>
<<<grid_dim, block_dim, 0, stream>>>(output_grad_data,
in_grad_data,
index_data,
size,
stride,
pre_size,
input_dim[dim]);
} else {
const int* index_data = index.data<int>();
index_select_grad_deterministic_cuda_kernel<T, int>
<<<grid_dim, block_dim, 0, stream>>>(output_grad_data,
in_grad_data,
index_data,
size,
stride,
pre_size,
input_dim[dim]);
}
} else {
unsigned int block_dim = PADDLE_CUDA_NUM_THREADS;
const uint64_t grid_x = (out_nums + block_dim - 1) / block_dim;
PADDLE_ENFORCE_LE_UINT32_MAX(grid_x, "grid.x");
dim3 grid_dim = dim3(static_cast<uint32_t>(grid_x));
backends::gpu::LimitGridDim(dev_ctx, &grid_dim);
if (index_type == DataType::INT64) {
const int64_t* index_data = index.data<int64_t>();
index_select_grad_cuda_kernel<T, int64_t>
<<<grid_dim, block_dim, 0, stream>>>(output_grad_data,
in_grad_data,
index_data,
out_nums,
stride,
size,
delta,
input_dim[dim]);
} else {
const int* index_data = index.data<int>();
index_select_grad_cuda_kernel<T, int>
<<<grid_dim, block_dim, 0, stream>>>(output_grad_data,
in_grad_data,
index_data,
out_nums,
stride,
size,
delta,
input_dim[dim]);
}
}
}
} // namespace phi
PD_REGISTER_KERNEL(index_select_grad,
GPU,
ALL_LAYOUT,
phi::IndexSelectGradKernel,
float,
double,
phi::float16,
phi::bfloat16,
phi::complex64,
phi::complex128,
int,
int64_t,
bool) {}