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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 "paddle/phi/common/amp_type_traits.h"
#include "paddle/phi/kernels/funcs/eigen/common.h"
#include "paddle/phi/kernels/funcs/eigen/eigen_function.h"
#include "paddle/phi/kernels/huber_loss_grad_kernel.h"
namespace phi {
template <typename T>
struct HuberLossBackward {
HOSTDEVICE HuberLossBackward(const T& delta, T sign)
: sign(sign), delta(delta) {}
HOSTDEVICE T operator()(const T& val) const {
T abs_val = abs(val);
if (abs_val <= delta) {
return sign * val;
} else {
if (val > static_cast<T>(0)) {
return sign * delta;
} else {
return static_cast<T>(-1) * sign * delta;
}
}
}
T sign;
T delta;
};
template <typename T, typename Context>
void HuberLossGradKernel(const Context& dev_ctx,
const DenseTensor& residual,
const DenseTensor& out_grad,
float delta,
DenseTensor* input_grad,
DenseTensor* label_grad) {
T delta_ = static_cast<T>(delta);
auto& place = *dev_ctx.eigen_device();
auto eigen_residual = EigenVector<T>::Flatten(residual);
auto eigen_out_grad = EigenVector<T>::Flatten(out_grad);
if (input_grad) {
dev_ctx.template Alloc<T>(input_grad);
auto eigen_input_grad = EigenVector<T>::Flatten(*input_grad);
eigen_input_grad.device(place) = eigen_residual.unaryExpr(
HuberLossBackward<T>(delta_, static_cast<T>(-1.0)));
eigen_input_grad.device(place) = eigen_out_grad * eigen_input_grad;
}
if (label_grad) {
dev_ctx.template Alloc<T>(label_grad);
auto eigen_label_grad = EigenVector<T>::Flatten(*label_grad);
eigen_label_grad.device(place) = eigen_residual.unaryExpr(
HuberLossBackward<T>(delta_, static_cast<T>(1.0)));
eigen_label_grad.device(place) = eigen_out_grad * eigen_label_grad;
}
}
} // namespace phi