矩阵转置函数时间性能测量(最差情形)
#include<stdio.h>
#include<time.h>
#define MAX_SIZE 100
#define SWAP(x, y, t) ((t)=(x), (x)=(y),(y)=t)
void transpose(int a[][MAX_SIZE],int n);
int main(void)
{
int step=10;
double duration;
clock_t start;
long repetitions;
int num=1,k=0;
int a[MAX_SIZE][MAX_SIZE];
printf(" n time\n");
for(int n=0; n<=100; n+=step)
{
repetitions=0;
num=1;
for(int i=0; i<n; i++)
{
for(int j=0;j<n; j++)
{
a[i][j]=num;
num++;
k++;
}
}
start=clock();
do{
repetitions++;
transpose(a, n);
}while((clock()-start)<1000);
//printf("%f %f", (double)start,(double)clock());
duration=((double)(clock()-start)/CLOCKS_PER_SEC);
duration/=repetitions;
printf("%6d %ld %.15lf %d\n", n*n, repetitions, duration, k);
// for(int i=0;i<n;i++)
// for(int j=0;j<n; j++)
// printf("%d ", a[i][j]);
//
// putchar('\n');
// if(n==100)
// step=100;
}
return 0;
}
void transpose(int a[][MAX_SIZE],int n)
{
int i,j,temp;
for(i=0; i<n; i++)
{
for(j=i+1; j<n; j++)
{
SWAP(a[i][j], a[j][i], temp);
}
}
}
posted on 2017-12-31 22:09 MACHINE_001 阅读(129) 评论(0) 编辑 收藏 举报