KmlScaissGmresSetUserPreconditioner?I
关联用户自定义预条件子回调函数,如不使用自定义的预条件子,该接口可以不使用。
接口定义
C Interface:
int KmlScaissGmresSetUserPreconditionerSI(KmlScasolverTask **handle, void *ustruct, int (*fptr)(void *ustruct, float *x));
int KmlScaissGmresSetUserPreconditionerDI(KmlScasolverTask **handle, void *ustruct, int (*fptr)(void *ustruct, double *x));
参数
参数名 |
类型 |
描述 |
输入/输出 |
---|---|---|---|
handle |
KmlScasolverTask ** |
求解器句柄,传入之前步骤的变量。 |
输入/输出 |
ustruct |
void * |
指向用户数据的指针,每次调用预条件子时作为第一个参数传递。 |
输入 |
(*fptr) |
int |
用户自定义的函数指针,指向回调函数,该回调函数进行预条件子与其第二参数间的计算。 |
输入 |
返回值
返回值 |
类型 |
描述 |
---|---|---|
KMLSS_NO_ERROR |
int |
正常执行。 |
KMLSS_NULL_ARGUMENT |
int |
handle,fptr中存在空参数。 |
依赖
#include "kml_scaiss.h"
示例
C Interface:
// USER data struct typedef struct { int n; const int *ia; const int *ja; const double *a; } duser; int diagonal_preconditioner(void *usr, double *x) { duser *u = (duser *)usr; int i, j; /* Apply diagonal preconditioner*/ for (i = 0; i < u->n; i++) { for (j = u->ia[i]; j < u->ia[i + 1]; j++) { if (u->ja[j] == i) x[i] /= u->a[j]; } } return 0; } MPI_Init(NULL, NULL); int size, rank; MPI_Comm_size(MPI_COMM_WORLD, &size);//获取总进程数 MPI_Comm_rank(MPI_COMM_WORLD, &rank);//获取当前进程标识 int mat_size = 8; int n = mat_size / size; int n_beg = n * rank; if (n * size != mat_size && rank == (size - 1)) { n = mat_size - n * rank; } int ja[26] = { 0, 3, 4, 1, 2, 3, 5, 1, 2, 7, 0, 1, 3, 6, 0, 4, 5, 1, 4, 5, 7, 3, 6, 2, 5, 7 }; double a[26] = { 1.0, 1.0, 2.0, 9.0, 2.0, 1.0, -3.0, 2.0, 3.0, 2.0, 1.0, 1.0, 9.0, -5.0, 2.0, 6.0, 1.0, -3.0, 1.0, 4.0, 1.0, -5.0, 7.0, 2.0, 1.0, 2.0 }; int ia[9] = { 0, 3, 7, 10, 14, 17, 21, 23, 26 }; int a_beg = ia[n_beg]; for (int i = n_beg; i < (n_beg + n + 1); i++) { ia[i] -= a_beg; } /* Internal KML_SCAISS structure */ KmlScasolverTask *handle; /* KML_SCAISS control parameters */ int error; /* Output error handle */ /* Create data structures */ const double *a_holder = &a[a_beg]; const int *ja_holder = &ja[a_beg]; const int *ia_holder = &ia[n_beg]; error = KmlScaissGmresInitStripesDI(&handle, mat_size, 1, &n, &n_beg, &a_holder, &ja_holder, &ia_holder, MPI_COMM_WORLD); duser prea; prea.n = n; prea.ia = &ia[n_beg]; prea.ja = &ja[a_beg]; prea.a = &a[a_beg]; error = KmlScaissGmresSetUserPreconditionerDI(&handle, &prea, &diagonal_preconditioner); if (error != 0) { printf("\nERROR in KmlScaissGmresSetUserPreconditionerDI: %d", error); return 1; }
父主题: SCAISS-GMRES