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paddlepaddle--paddle/paddle/phi/kernels/cpu/nanmedian_kernel.cc
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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/nanmedian_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/nanmedian_utils.h"
#include "paddle/phi/kernels/top_k_kernel.h"
namespace phi {
template <typename T, typename Context>
void CalcMedianFunc(const Context& dev_ctx,
const DenseTensor& x,
const std::vector<int64_t>& nan_counts,
const std::vector<int64_t>& nan_indice,
bool ignore_nan,
int64_t sort_k,
int64_t stride,
int64_t pre_dim,
T* o_ptr,
int64_t* m_ptr,
const std::string& mode) {
DenseTensor sort_out;
DenseTensor sort_indices;
auto sort_dim = x.dims();
int64_t rank = sort_dim.size();
sort_dim[static_cast<int>(rank - 1)] = sort_k;
sort_out.Resize(sort_dim);
sort_indices.Resize(sort_dim);
dev_ctx.template Alloc<T>(&sort_out);
T* sort_out_ptr = sort_out.data<T>();
dev_ctx.template Alloc<int64_t>(&sort_indices);
int64_t* sort_indices_ptr = sort_indices.data<int64_t>();
TopkKernel<T, Context>(
dev_ctx, x, Scalar(sort_k), -1, false, true, &sort_out, &sort_indices);
T div_factor = static_cast<T>(2.0);
int64_t offset = 0;
int64_t i = 0;
bool is_ori_odd = stride & 1;
if (ignore_nan) { // ignore_nan - has nan value; sort_k = max_valid_num
for (i = 0; i < pre_dim; i++) {
offset = i * sort_k;
if (nan_counts[i] == stride) {
if (mode == "avg") {
m_ptr[i * 2] = -1;
m_ptr[i * 2 + 1] = -1; // index is -1
} else {
m_ptr[i] = -1;
}
o_ptr[i] = sort_out_ptr[offset];
} else {
int64_t nan_k = nan_counts[i] > 0
? static_cast<int64_t>(stride - nan_counts[i])
: sort_k;
int64_t row_pos = static_cast<int64_t>(nan_k >> 1);
int64_t pos = offset + row_pos;
if (nan_k & 1) {
if (mode == "avg") {
m_ptr[2 * i] = sort_indices_ptr[pos];
m_ptr[2 * i + 1] = sort_indices_ptr[pos];
} else {
m_ptr[i] = sort_indices_ptr[pos];
}
o_ptr[i] = sort_out_ptr[pos];
} else {
// nan_k is even
T m_val_left =
row_pos > 0 ? sort_out_ptr[pos - 1] : sort_out_ptr[pos];
T m_val_right = sort_out_ptr[pos];
if (mode == "avg") {
m_ptr[2 * i] =
row_pos > 0 ? sort_indices_ptr[pos - 1] : sort_indices_ptr[pos];
m_ptr[2 * i + 1] = sort_indices_ptr[pos];
o_ptr[i] = (m_val_left + m_val_right) / div_factor;
} else {
// mode == "min": output median value should be the left val since
// the sort_out is in ascending order
m_ptr[i] =
row_pos > 0 ? sort_indices_ptr[pos - 1] : sort_indices_ptr[pos];
o_ptr[i] = m_val_left;
}
}
}
}
} else { // not ignore_nan - no nan value; sort_k = stride/2 + 1
if (is_ori_odd) {
for (i = 0; i < pre_dim; i++) {
if (nan_counts[i] > 0) {
o_ptr[i] = std::numeric_limits<T>::quiet_NaN();
m_ptr[i] = nan_indice[i];
continue;
}
offset = i * sort_k;
int64_t pos = offset + sort_k - 1;
o_ptr[i] = sort_out_ptr[pos];
if (mode == "avg") {
m_ptr[2 * i] = sort_indices_ptr[pos];
m_ptr[2 * i + 1] = sort_indices_ptr[pos];
} else {
m_ptr[i] = sort_indices_ptr[pos];
}
}
} else {
for (i = 0; i < pre_dim; i++) {
if (nan_counts[i] > 0) {
o_ptr[i] = std::numeric_limits<T>::quiet_NaN();
m_ptr[i] = nan_indice[i];
continue;
}
offset = i * sort_k;
int64_t pos = offset + sort_k - 1;
T m_val_left = sort_k > 1 ? sort_out_ptr[pos - 1] : sort_out_ptr[pos];
T m_val_right = sort_out_ptr[pos];
if (mode == "avg") {
m_ptr[2 * i] =
sort_k > 1 ? sort_indices_ptr[pos - 1] : sort_indices_ptr[pos];
m_ptr[2 * i + 1] = sort_indices_ptr[pos];
o_ptr[i] = (m_val_left + m_val_right) / div_factor;
} else {
// mode == "min": output median value should be the left val since the
// sort_out is in ascending order
m_ptr[i] =
sort_k > 1 ? sort_indices_ptr[pos - 1] : sort_indices_ptr[pos];
o_ptr[i] = m_val_left;
}
}
}
}
}
template <typename T, typename Context>
void ProcessMedianKernel(const Context& dev_ctx,
const DenseTensor& x,
const std::string& mode,
bool ignore_nan,
DenseTensor* out,
DenseTensor* median_index) {
const T* x_data = x.data<T>();
T* out_data = dev_ctx.template Alloc<T>(out);
int64_t* m_data = dev_ctx.template Alloc<int64_t>(median_index);
int64_t numel = x.numel();
auto x_dim = x.dims();
int64_t x_rank = x_dim.size();
int64_t stride = x_dim[static_cast<int>(x_rank - 1)];
PADDLE_ENFORCE_NE(stride,
0,
common::errors::InvalidArgument(
"The input Tensor x's shape[-1] should not "
"be 0, but shape is %s now.",
x_dim));
int64_t pre_dim = numel / stride;
int64_t i = 0;
int64_t max_valid_num = 0;
std::vector<int64_t> nan_counts;
std::vector<int64_t> nan_indice;
int64_t total_nan_num = 0;
std::vector<T> col_vec;
col_vec.reserve(stride);
col_vec.resize(stride);
nan_counts.clear();
nan_counts.reserve(pre_dim);
nan_counts.resize(pre_dim);
nan_indice.clear();
nan_indice.reserve(pre_dim);
nan_indice.resize(pre_dim);
for (int64_t i = 0; i < pre_dim; i++) {
col_vec.clear();
col_vec.insert(
col_vec.begin(), x_data + i * stride, x_data + (i + 1) * stride);
int64_t first_nan_idx = -1;
int64_t nan_count = 0;
for (int64_t j = 0; j < stride; ++j) {
if (std::isnan(static_cast<float>(col_vec[j]))) {
++nan_count;
if (first_nan_idx == -1) {
first_nan_idx = j;
}
}
}
nan_counts[i] = nan_count;
nan_indice[i] = first_nan_idx;
total_nan_num += nan_count;
if (stride - nan_count > max_valid_num) {
max_valid_num = stride - nan_count;
}
}
if (total_nan_num == numel) {
for (i = 0; i < pre_dim; i++) {
out_data[i] = std::numeric_limits<T>::quiet_NaN();
if (mode == "avg") {
m_data[2 * i] = numel / 2;
m_data[2 * i + 1] = numel / 2 - 1;
} else {
m_data[i] = numel / 2;
}
}
return;
}
int64_t sort_k = ignore_nan ? max_valid_num : ((stride >> 1) + 1);
CalcMedianFunc<T, Context>(dev_ctx,
x,
nan_counts,
nan_indice,
ignore_nan,
sort_k,
stride,
pre_dim,
out_data,
m_data,
mode);
}
template <typename T, typename Context>
void NanmedianKernel(const Context& dev_ctx,
const DenseTensor& x,
const IntArray& axes,
bool keepdim UNUSED,
const std::string& mode,
DenseTensor* out,
DenseTensor* median_index) {
if (x.numel() == 0) {
Full<T, Context>(dev_ctx, out->dims(), NAN, out);
Full<int64_t, Context>(dev_ctx, median_index->dims(), 0, median_index);
return;
}
DenseTensor tmp_x;
auto rank = x.dims().size();
if ((axes.size() == 0) || rank <= 1) {
tmp_x = x;
tmp_x.Resize({x.numel()}); // flatten
} else {
funcs::PreprocessMedianKernel<T, Context>(
dev_ctx,
x,
axes,
&tmp_x); // resize to 2D so as to compute median on last axis
}
ProcessMedianKernel<T, Context>(
dev_ctx, tmp_x, mode, true, out, median_index);
}
} // namespace phi
PD_REGISTER_KERNEL(nanmedian,
CPU,
ALL_LAYOUT,
phi::NanmedianKernel,
float,
double,
int,
int64_t) {
kernel->OutputAt(1).SetDataType(phi::DataType::INT64);
}