---
title: KmlScaissCgSolve?I
description: "求解线性代数方程组。"
url: https://www.hikunpeng.com/document/detail/zh/kunpengboostkithistory/2200/accel/kunpengaccel_kml_16_0380.html
sourcePath: /source/zh/kunpengboostkithistory/2200/accel/kunpengaccel_kml_16_0380.html
indexId: f6efc2431a7f9a713f9bdfbede1e0bb42f7330ccd276003446cfeb475517cf2d74
---
# KmlScaissCgSolve?I

求解线性代数方程组。

#### 接口定义

C Interface：

int KmlScaissCgSolveSI(KmlScasolverTask **handle, int nb, float *x, int ldx, const float *b, int ldb);

int KmlScaissCgSolveDI(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KmlScaissCgSolveSI中为float \*。 在KmlScaissCgSolveDI中为double \*。 | 读取并存储全局求解结果，其元素个数为n。 | 输入/输出 |
| ldx | int | x的leading dimension大小，当前参数未使用。 | 输入 |
| b | 在KmlScaissCgSolveSI中为const float \*。 在KmlScaissCgSolveDI中为const double \*。 | 读取进程对应的局部右端项，其元素个数为stripeWidth[0]。 | 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 n = 8 / size;
int n_beg = n * rank;
if (n * size != 8 && rank == (size - 1)) {
n = 8 - 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, 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 < 9; i++) {
ia[i] -= a_beg;
}
/* Internal KML_SCAISS structure */
KmlScasolverTask *handle;
/* KML_SCAISS control parameters */
int nrhs = 1;         /* Number of right-hand sides */
int ldx = 8, ldb = 8; /*!Leading dimension of B and X */
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, 8, 1, &n, &n_beg, &a_holder, &ja_holder, &ia_holder, MPI_COMM_WORLD);
double eps = 1e-4;
ierr = KmlScaissCgSetDID(&handle, KMLSS_THRESHOLD, &eps, 1);
int max_iters = 2000;
ierr = KmlScaissCgSetDII(&handle, KMLSS_MAX_ITERATION_COUNT, &max_iters, 1);
ierr = KmlScaissCgSolveDI(&handle, nrhs, &x[0], ldx, &b[n_beg], ldb);
if (error != 0) {
printf("\nERROR in KmlScaissCgSolveDI: %d", error);
return 1;
}
```