OpenMP版本的矩阵矩阵乘法
时间: 2023-12-03 19:03:43 浏览: 30
好的,以下是 OpenMP 版本的矩阵矩阵乘法的示例代码:
```c++
#include <omp.h>
#include <stdio.h>
#include <stdlib.h>
#define NRA 1000 /* number of rows in matrix A */
#define NCA 1000 /* number of columns in matrix A */
#define NCB 1000 /* number of columns in matrix B */
int main (int argc, char *argv[])
{
int tid, nthreads, i, j, k;
double a[NRA][NCA], /* matrix A to be multiplied */
b[NCA][NCB], /* matrix B to be multiplied */
c[NRA][NCB]; /* result matrix C */
/* Initialize matrices */
for (i=0; i<NRA; i++)
for (j=0; j<NCA; j++)
a[i][j]= i+j;
for (i=0; i<NCA; i++)
for (j=0; j<NCB; j++)
b[i][j]= i*j;
for (i=0; i<NRA; i++)
for (j=0; j<NCB; j++)
c[i][j]= 0;
/* Perform matrix multiplication */
#pragma omp parallel shared(a,b,c) private(tid,i,j,k)
{
tid = omp_get_thread_num();
if (tid == 0)
{
nthreads = omp_get_num_threads();
printf("Starting matrix multiplication with %d threads\n",nthreads);
}
#pragma omp for schedule(static)
for (i=0; i<NRA; i++)
{
printf("Thread=%d did row=%d\n",tid,i);
for(j=0; j<NCB; j++)
for (k=0; k<NCA; k++)
c[i][j] += a[i][k] * b[k][j];
}
}
/* Print results */
printf("******************************************************\n");
printf("Result Matrix:\n");
for (i=0; i<NRA; i++)
{
for (j=0; j<NCB; j++)
printf("%6.2f ", c[i][j]);
printf("\n");
}
printf("******************************************************\n");
printf ("Done.\n");
return 0;
}
```
在这个示例代码中,我们使用了 `#pragma omp parallel` 和 `#pragma omp for` 来并行化矩阵乘法的计算过程。其中,`#pragma omp parallel` 用于创建一个并行区域,`#pragma omp for` 用于将矩阵的行分配给不同的线程进行计算。在 `#pragma omp parallel` 中,我们使用了 `shared` 和 `private` 来指定变量的共享和私有属性。