liblcg/src/lib/preconditioner.h
2024-09-11 13:39:28 +08:00

110 lines
5.5 KiB
C

/******************************************************
* C++ Library of the Linear Conjugate Gradient Methods (LibLCG)
*
* Copyright (C) 2022 Yi Zhang (yizhang-geo@zju.edu.cn)
*
* LibLCG is distributed under a dual licensing scheme. You can
* redistribute it and/or modify it under the terms of the GNU Lesser
* General Public License (LGPL) as published by the Free Software Foundation,
* either version 2 of the License, or (at your option) any later version.
* You should have received a copy of the GNU Lesser General Public
* License along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* If the terms and conditions of the LGPL v.2. would prevent you from
* using the LibLCG, please consider the option to obtain a commercial
* license for a fee. These licenses are offered by the LibLCG developing
* team. As a rule, licenses are provided "as-is", unlimited in time for
* a one time fee. Please send corresponding requests to: yizhang-geo@zju.edu.cn.
* Please do not forget to include some description of your company and the
* realm of its activities. Also add information on how to contact you by
* electronic and paper mail.
******************************************************/
#ifndef _PRECONDITIONER_H
#define _PRECONDITIONER_H
#include "algebra.h"
/**
* @brief Return the number of non-zero elements in the lower triangular part of the input matrix
*
* @param row[in] Row index of the input sparse matrix.
* @param col[in] Column index of the input sparse matrix.
* @param nz_size[in] Length of the non-zero elements.
* @param lnz_size[out] Legnth of the non-zero elements in the lower triangle
*/
void lcg_incomplete_Cholesky_half_buffsize_coo(const int *row, const int *col, int nz_size, int *lnz_size);
/**
* @brief Preform the incomplete Cholesky factorization for a sparse matrix that is saved in the COO format.
*
* @note Only the factorized lower triangular matrix is stored in the lower part of the output matrix accordingly.
*
* @param row Row index of the input sparse matrix.
* @param col Column index of the input sparse matrix.
* @param val Non-zero values of the input sparse matrix.
* @param N Row/Column size of the sparse matrix.
* @param nz_size Length of the non-zero elements.
* @param lnz_size Legnth of the non-zero elements in the lower triangle
* @param IC_row Row index of the factorized triangular sparse matrix.
* @param IC_col Column index of the factorized triangular sparse matrix.
* @param IC_val Non-zero values of the factorized triangular sparse matrix.
*/
void lcg_incomplete_Cholesky_half_coo(const int *row, const int *col, const lcg_float *val, int N, int nz_size, int lnz_size, int *IC_row, int *IC_col, lcg_float *IC_val);
/**
* @brief Preform the incomplete Cholesky factorization for a sparse matrix that is saved in the COO format.
*
* @note The factorized lower and upper triangular matrixes are stored in the lower and upper triangular parts of the output matrix accordingly.
*
* @param row Row index of the input sparse matrix.
* @param col Column index of the input sparse matrix.
* @param val Non-zero values of the input sparse matrix.
* @param N Row/Column size of the sparse matrix.
* @param nz_size Length of the non-zeor elements.
* @param IC_row Row index of the factorized triangular sparse matrix.
* @param IC_col Column index of the factorized triangular sparse matrix.
* @param IC_val Non-zero values of the factorized triangular sparse matrix.
*/
void lcg_incomplete_Cholesky_full_coo(const int *row, const int *col, const lcg_float *val, int N, int nz_size, int *IC_row, int *IC_col, lcg_float *IC_val);
/**
* @brief Solve the linear system Ux = B, in which U is a upper triangle matrix.
*
* @param row Row index of the input sparse matrix.
* @param col Column index of the input sparse matrix.
* @param U Non-zero values of the input sparse matrix.
* @param B Object array.
* @param x The returned solution.
* @param N Row/Column size of the sparse matrix.
* @param nz_size Length of the non-zeor elements.
*/
void lcg_solve_upper_triangle_coo(const int *row, const int *col, const lcg_float *U, const lcg_float *B, lcg_float *x, int N, int nz_size);
/**
* @brief Solve the linear system Lx = B, in which L is a lower triangle matrix.
*
* @param row Row index of the input sparse matrix.
* @param col Column index of the input sparse matrix.
* @param L Non-zero values of the input sparse matrix.
* @param B Object array.
* @param x The returned solution.
* @param N Row/Column size of the sparse matrix.
* @param nz_size Length of the non-zeor elements.
*/
void lcg_solve_lower_triangle_coo(const int *row, const int *col, const lcg_float *L, const lcg_float *B, lcg_float *x, int N, int nz_size);
/**
* @brief Check to see if a square matrix is full ranked or not. The sparse matrix is stored in the COO format.
*
* @param row Row index of the input sparse matrix.
* @param col Column index of the input sparse matrix.
* @param M Non-zero values of the input sparse matrix.
* @param N Row/Column size of the sparse matrix.
* @param nz_size Length of the non-zeor elements.
* @return true The matrix is full ranked.
* @return false The matrix is not full ranked.
*/
bool lcg_full_rank_coo(const int *row, const int *col, const lcg_float *M, int N, int nz_size);
#endif // _PRECONDITIONER_H