KmlScaissGmresSolveDx?I
求解线性代数方程组,每个进程读取并存储当前进程对应的求解结果。
接口定义
C Interface:
int KmlScaissGmresSolveSI(KmlScasolverTask **handle, int nb, float *x, int ldx, const float *b, int ldb);
int KmlScaissGmresSolveDI(KmlScasolverTask **handle, int nb, double *x, int ldx, const double *b, int ldb);
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 |
nb |
int |
右端项矢量的个数,当前nb只能为1。 |
输入 |
x |
|
读取并存储当前进程对应的求解结果,其元素个数为当前进程对应的矩阵的行数,即stripeWidth。 |
输入/输出 |
ldx |
int |
x的leading dimension大小,当前参数未使用。 |
输入 |
b |
|
读取进程对应的局部右端项,其元素个数为当前进程对应的矩阵的行数,即stripeWidth。 |
输入 |
ldb |
int |
b的leading dimension大小,当前参数未使用。 |
输入 |
返回值
返回值 |
类型 |
描述 |
---|---|---|
KMLSS_NO_ERROR |
int |
正常执行。 |
KMLSS_BAD_NB |
int |
参数nb不等于1。 |
KML_NO_MEMORY |
int |
内存不足。 |
KMLSS_NULL_ARGUMENT |
int |
handle,x,b中存在空参数。 |
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 = KmlScaissGmresInitStripesDI(&handle, mat_size, 1, &n, &n_beg, &a_holder, &ja_holder, &ia_holder, MPI_COMM_WORLD); double eps = 1e-4; error = KmlScaissGmresSetDID(&handle, KMLSS_THRESHOLD, &eps, 1); if (error != 0) { printf("\nERROR in KmlScaissGmresSetDID with KMLSS_THRESHOLD: %d", error); return 1; } int max_iters = 2000; error = KmlScaissGmresSetDII(&handle, KMLSS_MAX_ITERATION_COUNT, &max_iters, 1); if (error != 0) { printf("\nERROR in KmlScaissGmresSetDII with KMLSS_MAX_ITERATION_COUNT: %d", error); return 1; } int precond = KMLSS_BJACOBI; error = KmlScaissGmresSetDII(&handle, KMLSS_PRECONDITIONER_TYPE, &precond, 1); if (error != 0) { printf("\nERROR in KmlScaissGmresSetDII with KMLSS_PRECONDITIONER_TYPE: %d", error); return 1; } int num_blocks = 1; error = KmlScaissGmresPcSetDII(&handle, KMLSS_NUM_BLOCKS, &num_blocks, 1); if (error != 0) { printf("ERROR in KmlScaissGmresPcSetDII: %d\n", error); return 1; } int subprecond = KMLSS_ICC; error = KmlScaissGmresPcSetDII(&handle, KMLSS_BLOCK_METHOD, &subprecond, 1); if (error != 0) { printf("ERROR in KmlScaissGmresPcSetDII: %d\n", error); return 1; } error = KmlScaissGmresAnalyzeDI(&handle); if (error != 0) { printf("ERROR in KmlScaissGmresAnalyzeDI: %d\n", error); return 1; } error = KmlScaissGmresFactorizeDI(&handle); if (error != 0) { printf("ERROR in KmlScaissGmresFactorizeDI: %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 = KmlScaissGmresSolveDxDI(&handle, nrhs, &x[n_beg], ldx, &b[n_beg], ldb); if (error != 0) { printf("ERROR in KmlScaissGmresSolveDI: %d\n", error); return 1; }
父主题: SCAISS-GMRES