KmlScaissCgGet?I?

获得迭代求解相关参数。

接口定义

C Interface：

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

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

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

int KmlScaissCgGetDID(KmlScasolverTask **handle, enum KmlSolverParam param, 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_ITERATION_COUNT表示迭代次数。 KMLSS_MAX_ITERATION_COUNT表示设置的最大迭代次数。 KMLSS_TOLERANCE表示最终的迭代相对残差。 KMLSS_THRESHOLD表示设置的相对残差。	输入
data	在KmlScaissCgGetSII/KmlScaissCgGetDII中为int 。在KmlScaissCgGetSIS中为float 。在KmlScaissCgGetDID中为double *。	在KmlScaissCgGetSII/KmlScaissCgGetDII中为迭代步数。在KmlScaissCgGetSIS中为残差。在KmlScaissCgGetDID中为残差。	输出
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。

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;
}
int num_blocks = 1;
error = KmlScaissCgPcSetDII(&handle, KMLSS_NUM_BLOCKS, &num_blocks, 1);
if (error != 0) {
	printf("ERROR in KmlScaissCgPcSetDII: %d\n", error);
	return 1;
}
int subprecond = KMLSS_ICC;
error = KmlScaissCgPcSetDII(&handle, KMLSS_BLOCK_METHOD, &subprecond, 1);
if (error != 0) {
    printf("ERROR in KmlScaissCgPcSetDII: %d\n", error);
    return 1;
}
error = KmlScaissCgAnalyzeDI(&handle);
if (error != 0) {
    printf("ERROR in KmlScaissCgAnalyzeDI: %d\n", error);
    return 1;
}
error = KmlScaissCgFactorizeDI(&handle);
if (error != 0) {
    printf("ERROR in KmlScaissCgFactorizeDI: %d\n", error);
    return 1;
}

int nrhs = 1;
int ldx = n, ldb = n;
double b[8] = { 4.0, 9.0, 7.0, 6.0, 9.0, 3.0, 2.0, 5.0 };
double x[8] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };
error = KmlScaissCgSolveDxDI(&handle, nrhs, &x[n_beg], ldx, &b[n_beg], ldb);
if (error != 0) {
    printf("ERROR in KmlScaissCgSolveDI: %d\n", error);
    return 1;
}

int idata[] = {0};
error = KmlScaissCgGetDII(&handle, KMLSS_ITERATION_COUNT, idata, 1); 
if (error != 0) {
    printf("\nERROR in KmlScaissCgGetDII: %d", error);
    return 1;
    }
double ddata[] = {0.0};
error = KmlScaissCgGetDID(&handle, KMLSS_TOLERANCE, ddata, 1);
if (error != 0) {
    printf("\nERROR in KmlScaissCgGetDID: %d", error);
    return 1;
    }
if (rank == 0) printf("[Solve info] Res= \t%.12g\t, iteration = \t%d\t\n", sqrt(ddata[0]), idata[0]);

运行结果（2个进程）：

[Solve info] Res=      2.04475505752e-15       , iteration =   8

父主题： SCAISS-CG