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

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// Copyright (c) 2025 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/lu_solve_kernel.h"
#include "paddle/phi/backends/cpu/cpu_context.h"
#include "paddle/phi/core/enforce.h"
#include "paddle/phi/core/kernel_registry.h"
#include "paddle/phi/kernels/funcs/lapack/lapack_function.h"
#include "paddle/phi/kernels/impl/lu_kernel_impl.h"
namespace phi {
template <typename T, typename Context>
void LuSolveKernel(const Context& dev_ctx,
const DenseTensor& b,
const DenseTensor& lu,
const DenseTensor& pivots,
const std::string& trans,
DenseTensor* out) {
// Get lu matrix dimensions
auto lu_dims = lu.dims();
// Get x matrix dimensions
auto x_dims = b.dims();
// Allocate output tensor
dev_ctx.template Alloc<T>(out);
// Copy RHS data to output (will be overwritten with solution)
*out = Transpose2DTo6D<Context, T>(dev_ctx, b);
DenseTensor tem_lu = Transpose2DTo6D<Context, T>(dev_ctx, lu);
// Prepare LAPACK parameters
char trans_char = (trans == "N") ? 'N' : ((trans == "T") ? 'T' : 'C');
auto n_last_dim = lu_dims[lu_dims.size() - 1];
PADDLE_ENFORCE_LE_INT_MAX(
n_last_dim,
"TODO(large-tensor): LAPACK input n does not support int64 overflow.");
int n_int = static_cast<int>(n_last_dim);
auto nrhs_last_dim = x_dims[x_dims.size() - 1];
PADDLE_ENFORCE_LE_INT_MAX(nrhs_last_dim,
"TODO(large-tensor): LAPACK nrhs does not "
"support int64 overflow.");
int nrhs_int = static_cast<int>(nrhs_last_dim);
int lda = std::max(1, n_int); // Leading dimension of A (LU matrix)
int ldb = std::max(1, n_int); // Leading dimension of B (RHS/solution matrix)
int info = 0;
auto outdims = out->dims();
auto outrank = outdims.size();
auto batchsize_64 = product(slice_ddim(outdims, 0, outrank - 2));
PADDLE_ENFORCE_LE_INT_MAX(
batchsize_64,
"TODO(large-tensor): LAPACK batch size does not support int64 overflow.");
int batchsize = static_cast<int>(batchsize_64);
auto out_data = out->data<T>();
auto lu_data = tem_lu.data<T>();
auto pivots_data =
reinterpret_cast<int*>(const_cast<int*>(pivots.data<int>()));
for (int i = 0; i < batchsize; i++) {
auto* out_data_item = &out_data[i * lda * nrhs_int];
auto* lu_data_item = &lu_data[i * ldb * n_int];
auto* pivots_data_item = &pivots_data[i * n_int];
funcs::lapackLuSolve<T>(trans_char,
n_int,
nrhs_int,
lu_data_item,
lda,
pivots_data_item,
out_data_item,
ldb,
&info);
PADDLE_ENFORCE_EQ(
info,
0,
common::errors::PreconditionNotMet(
"LU solve failed with error code %d. Check if matrix is singular.",
info));
}
*out = Transpose2DTo6D<Context, T>(dev_ctx, *out);
}
} // namespace phi
PD_REGISTER_KERNEL(lu_solve,
CPU,
ALL_LAYOUT,
phi::LuSolveKernel,
float,
double,
phi::complex64,
phi::complex128) {}