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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/p_norm_kernel.h"
#include "paddle/phi/backends/cpu/cpu_context.h"
#include "paddle/phi/core/kernel_registry.h"
#include "paddle/phi/kernels/full_kernel.h"
#include "paddle/phi/kernels/funcs/common_shape.h"
#include "paddle/phi/kernels/funcs/eigen/common.h"
#include "paddle/phi/kernels/funcs/eigen/eigen_function.h"
#include "paddle/phi/kernels/funcs/math_function.h"
namespace phi {
inline void GetDims(
const DDim& dim, int axis, int* pre, int* n, int* post, bool asvector) {
*pre = 1;
*post = 1;
*n = static_cast<int>(dim[axis]);
if (asvector) {
*n = static_cast<int>(product(dim));
} else {
for (int i = 0; i < axis; ++i) {
(*pre) *= static_cast<int>(dim[i]);
}
for (int i = axis + 1; i < dim.size(); ++i) {
(*post) *= static_cast<int>(dim[i]);
}
}
}
template <typename T, typename Context>
void PNormKernel(const Context& dev_ctx,
const DenseTensor& x,
double porder,
int axis,
float epsilon UNUSED,
bool keepdim UNUSED,
bool asvector,
DenseTensor* out) {
auto* in_x = &x;
dev_ctx.template Alloc<T>(out);
auto xdim = in_x->dims();
if (axis < 0) axis = xdim.size() + axis;
int pre = 0, n = 0, post = 0;
GetDims(xdim, axis, &pre, &n, &post, asvector);
if (x.numel() == 0) {
if (out->numel() > 0) {
std::vector<int64_t> vec_dims = vectorize(out->dims());
Full<T, Context>(dev_ctx, vec_dims, static_cast<T>(0), out);
}
return;
}
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(*in_x);
auto norm_e = EigenVector<T>::Flatten(*out);
auto xr = x_e.reshape(shape);
auto norm = norm_e.reshape(norm_shape);
// p=0 means number of non-zero elements of (xr)
// p=inf means the maximum of |xr|
// p=-inf means the minimum of |xr|
// otherwise, Lp-norm = pow(sum(pow(|xr|, p)), 1/p)
Eigen::DSizes<int, 1> rdim(1);
if (porder == 0) {
norm.device(*place) = (xr != xr.constant(0)).template cast<T>().sum(rdim);
} else if (porder == INFINITY) {
norm.device(*place) = xr.abs().maximum(rdim);
} else if (porder == -INFINITY) {
norm.device(*place) = xr.abs().minimum(rdim);
} else {
norm.device(*place) = xr.abs().pow(porder).sum(rdim).pow(1.0 / porder);
}
}
} // namespace phi
PD_REGISTER_KERNEL(p_norm, CPU, ALL_LAYOUT, phi::PNormKernel, float, double) {}