---
title: KmlScaissGmresSolve?I
description: "求解线性代数方程组，每个进程读取并存储全局求解结果。"
url: https://www.hikunpeng.com/document/detail/zh/kunpengboostkithistory/240RC2/accel/kunpengaccel_kml_17_0093.html
sourcePath: /source/zh/kunpengboostkithistory/240RC2/accel/kunpengaccel_kml_17_0093.html
indexId: febf5ca78e4b73a86d21edc4f4f706ae71a64e351dd103ac7e2ba7af34c1612876
---
# KmlScaissGmresSolve?I

求解线性代数方程组，每个进程读取并存储全局求解结果。

#### 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 | 在KmlScaissGmresSolveSI中为float \*。 在KmlScaissGmresSolveDI中为double \*。 | 读取并存储全局求解结果，其元素个数为全局矩阵大小n。 | 输入/输出 |
| ldx | int | x的leading dimension大小，当前参数未使用。 | 输入 |
| b | 在KmlScaissGmresSolveSI中为const float \*。 在KmlScaissGmresSolveDI中为const double \*。 | 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 = mat_size, 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[0], ldx, &b[n_beg], ldb);
if (error != 0) {
printf("ERROR in KmlScaissGmresSolveDI: %d\n", error);
return 1;
}
```