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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.
#include "paddle/phi/kernels/norm_kernel.h"
#include "paddle/phi/backends/cpu/cpu_context.h"
#include "paddle/phi/core/kernel_registry.h"
#include "paddle/phi/kernels/funcs/common_shape.h"
#include "paddle/phi/kernels/funcs/eigen/eigen_function.h"
#include "paddle/phi/kernels/funcs/math_function.h"
namespace phi {
template <typename T, typename Context>
void NormKernel(const Context& dev_ctx,
const DenseTensor& x,
int axis,
float epsilon,
bool is_test,
DenseTensor* out,
DenseTensor* norm) {
auto xdim = x.dims();
T eps = epsilon;
if (axis < 0) axis = xdim.size() + axis;
int64_t pre = 0, n = 0, post = 0;
funcs::GetPrePostNumel(xdim, axis, &pre, &n, &post);
DenseTensor* out_norm = nullptr;
DenseTensor out_norm_tmp;
if (is_test) {
auto out_dim = x.dims();
out_dim[axis] = 1;
out_norm = &out_norm_tmp;
out_norm->Resize(out_dim);
} else {
out_norm = norm;
}
dev_ctx.template Alloc<T>(out);
dev_ctx.template Alloc<T>(out_norm);
auto* place = dev_ctx.eigen_device();
Eigen::DSizes<int64_t, 3> shape(pre, n, post);
Eigen::DSizes<int64_t, 2> norm_shape(pre, post);
auto x_e = EigenVector<T>::Flatten(x);
auto y_e = EigenVector<T>::Flatten(*out);
auto norm_e = EigenVector<T>::Flatten(*out_norm);
auto x_r = x_e.reshape(shape);
auto y = y_e.reshape(shape);
auto norm_reshape = norm_e.reshape(norm_shape);
Eigen::DSizes<int, 1> rdim(1);
// y = x / sqrt((sum(x * x) + epsilon))
// norm = sqrt(sum(x * x) + epsilon)
auto x2 = x_r * x_r;
auto sum = x2.sum(rdim) + eps;
norm_reshape.device(*place) = sum.sqrt();
// y = x / norm
Eigen::DSizes<int64_t, 3> rshape(pre, static_cast<int64_t>(1), post);
Eigen::DSizes<int64_t, 3> bcast(
static_cast<int64_t>(1), n, static_cast<int64_t>(1));
y.device(*place) = x_r / norm_reshape.reshape(rshape).broadcast(bcast);
}
} // namespace phi
PD_REGISTER_KERNEL(norm, CPU, ALL_LAYOUT, phi::NormKernel, float, double) {}