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2026-07-13 12:40:42 +08:00

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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.
#pragma once
#include <vector>
#include "paddle/phi/core/dense_tensor.h"
#include "paddle/phi/kernels/empty_kernel.h"
#include "paddle/phi/kernels/funcs/eigen/common.h"
#include "paddle/phi/kernels/funcs/math_function.h"
namespace phi {
template <typename T, typename Context>
void WarprnntGradKernel(const Context& dev_ctx,
const DenseTensor& input UNUSED,
const DenseTensor& input_lengths UNUSED,
const DenseTensor& warprnntgrad,
const DenseTensor& loss_grad,
int blank UNUSED,
float fastemit_lambda UNUSED,
DenseTensor* input_grad) {
dev_ctx.template Alloc<T>(input_grad);
int64_t B = warprnntgrad.dims()[0];
int64_t Tmax = warprnntgrad.dims()[1];
int64_t Umax = warprnntgrad.dims()[2];
int64_t D = warprnntgrad.dims()[3];
// (B,)
auto loss_grad_e = EigenTensor<T, 1>::From(loss_grad);
// (B, T, U, D)
auto warprnntgrad_e = EigenTensor<T, 4>::From(warprnntgrad);
auto acts_grad_e = EigenTensor<T, 4>::From(*input_grad);
Eigen::DSizes<int64_t, 4> grad_shape(B, 1, 1, 1);
Eigen::DSizes<int64_t, 4> bcast(1, Tmax, Umax, D);
auto acts_g =
warprnntgrad_e * loss_grad_e.reshape(grad_shape).broadcast(bcast).eval();
auto* place = dev_ctx.eigen_device();
acts_grad_e.device(*place) = acts_g;
}
} // namespace phi