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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/kthvalue_grad_kernel.h"
#include "paddle/phi/backends/gpu/gpu_context.h"
#include "paddle/phi/core/kernel_registry.h"
#include "paddle/phi/kernels/funcs/math_function.h"
#include "paddle/phi/kernels/funcs/top_k_function_cuda.h"
namespace phi {
static int getBlockSize(int64_t col) {
if (col > 512)
return 1024;
else if (col > 256 && col <= 512)
return 512;
else if (col > 128 && col <= 256)
return 256;
else if (col > 64 && col <= 128)
return 128;
else
return 64;
}
template <typename T, typename Context>
void KthvalueGradKernel(const Context& dev_ctx,
const DenseTensor& x,
const DenseTensor& indices,
const DenseTensor& d_out,
int64_t k,
int axis,
bool keepdim,
DenseTensor* d_x) {
const auto& in_dims = x.dims();
auto out_dims = indices.dims();
T* x_grad_data = dev_ctx.template Alloc<T>(d_x);
if (d_x && d_x->numel() == 0) {
return;
}
// For 0D Tensor
if (in_dims.size() == 0) {
funcs::set_constant(dev_ctx, d_x, static_cast<T>(1.0));
return;
}
if (axis < 0) axis += in_dims.size();
const T* out_grad_data = d_out.data<T>();
const int64_t* indices_data = indices.data<int64_t>();
int64_t pre, n, post;
funcs::GetDims(in_dims, axis, &pre, &n, &post);
int block_size = getBlockSize(post * k);
int max_threads = dev_ctx.GetMaxPhysicalThreadCount();
const int64_t max_blocks = std::max(((max_threads - 1) / block_size + 1), 1);
int64_t desired_grid_size = std::min(max_blocks, pre);
int64_t grid_size =
std::min(desired_grid_size,
static_cast<int64_t>(dev_ctx.GetCUDAMaxGridDimSize()[0]));
funcs::AssignGradWithAxis<T>
<<<grid_size, block_size, 64 * 4, dev_ctx.stream()>>>(
out_grad_data, indices_data, x_grad_data, pre, post, n, 1);
}
} // namespace phi
PD_REGISTER_KERNEL(kthvalue_grad,
GPU,
ALL_LAYOUT,
phi::KthvalueGradKernel,
float,
double,
int,
int64_t,
phi::bfloat16,
phi::float16) {}