程序计算随机生成的矩阵与向量相乘
函数f():单线程计算
函数fp():多线程并行计算
#include <stdio.h>
#include <omp.h>
#include <stdlib.h>
#include <time.h>
const int NUM_THREADS = 20;
typedef long long ll;
int m = 10000, n = 10000;
int mat[10000][10000];
int vec[10000], ans[10000];
void makeRandomMatrix()
{
srand(time(NULL));
int i, j;
for (i = 0; i < m; i++)
{
for (j = 0; j < n; j++)
{
mat[i][j] = rand() % 10 + 1;
}
}
}
void makeRandomVector()
{
srand(time(NULL));
int i;
for (i = 0; i < n; i++)
{
vec[i] = rand() % 10 + 1;
}
}
void funy(int a[], int cur)
{
int i;
for (i = 0; i < n; i++)
{
ans[cur] += a[i] * vec[i];
}
}
void f()
{
int i;
for (i = 0; i < m; i++)
{
funy(mat[i], i);
}
}
void fp()
{
int i;
#pragma omp parallel
{
int id = omp_get_thread_num();
#pragma omp parallel for
for (i = id; i < m; i += NUM_THREADS)
{
funy(mat[i], i);
}
}
}
int main()
{
printf("Makeing matrix(10000*10000) & vector(10000*1)...\n");
makeRandomMatrix();
makeRandomVector();
double start_time = omp_get_wtime();
f();
// for (int i = 0; i < m; i ++) printf("%d%c\n", ans[i], ' \n'[i==n-1]);
double end_time = omp_get_wtime();
printf("1 thread --- Running time=%f s\n", end_time - start_time);
start_time = omp_get_wtime();
fp();
end_time = omp_get_wtime();
// for (int i = 0; i < m; i ++) printf("%d%c\n", ans[i], ' \n'[i==n-1]);
printf("20 threads --- Running time=%f s\n", end_time - start_time);
return 0;
}