KmlScaissCgSet?I?

设置迭代求解的相关参数。

接口定义

C Interface：

int KmlScaissCgSetSII(KmlScasolverTask **handle, enum KmlSolverParam param, const int *data, int nd);

int KmlScaissCgSetSIS(KmlScasolverTask **handle, enum KmlSolverParam param, const float *data, int nd);

int KmlScaissCgSetDII(KmlScasolverTask **handle, enum KmlSolverParam param, const int *data, int nd);

int KmlScaissCgSetDID(KmlScasolverTask **handle, enum KmlSolverParam param, const double *data, int nd);

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
param	enum KmlSolverParam	KMLSS_THRESHOLD表示迭代残差相对阈值。 KMLSS_ABS_TOLERANCE表示迭代残差绝对阈值。 KMLSS_MAX_ITERATION_COUNT表示最大迭代次数。 KMLSS_PRECONDITIONER_TYPE表示预条件子类型。	输入
data	在KmlScaissCgSetSII/ KmlScaissCgSetDII中为const int 。在KmlScaissCgSetSIS中为const float 。在KmlScaissCgSetDID中为const double *。	迭代求解相关参数数组（如阈值、最大迭代次数等）。当前可选择的预条件子类型： JACOBI预条件子：KMLSS_JACOBI BLOCK JACOBI预条件子：KMLSS_BJACOBI	输入
nd	int	data数组元素个数。	输入

返回值

返回值	类型	描述
KMLSS_NO_ERROR	int	正常执行。
KMLSS_DATA_SIZE	int	参数nd不等于1。
KMLSS_NULL_ARGUMENT	int	handle，data中存在空参数。
KMLSS_BAD_SELECTOR	int	param为无效参数。
KMLSS_BAD_PRECONDITIONER	int	选择的预条件子暂未实现。

依赖

#include "kml_scaiss.h"

示例

C Interface：

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 = KmlScaissCgInitStripesDI(&handle, mat_size, 1, &n, &n_beg, &a_holder, &ja_holder, &ia_holder, MPI_COMM_WORLD);

double eps = 1e-4;
error = KmlScaissCgSetDID(&handle, KMLSS_THRESHOLD, &eps, 1); 
if (error != 0) {
    printf("\nERROR in KmlScaissCgSetDID with KMLSS_THRESHOLD: %d", error);
    return 1;
}
int max_iters = 2000;
error = KmlScaissCgSetDII(&handle, KMLSS_MAX_ITERATION_COUNT, &max_iters, 1);
if (error != 0) {
    printf("\nERROR in KmlScaissCgSetDII with KMLSS_MAX_ITERATION_COUNT: %d", error);
    return 1;
}
int precond = KMLSS_BJACOBI;
error = KmlScaissCgSetDII(&handle, KMLSS_PRECONDITIONER_TYPE, &precond, 1);
if (error != 0) {
    printf("\nERROR in KmlScaissCgSetDII with KMLSS_PRECONDITIONER_TYPE: %d", error);
    return 1;
}

父主题： SCAISS-CG