r305_dm/TP1/Exo3/ij_ji.c

/* accès mémoire */

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#define N 8192

int t[N][N];

static inline double tstamp(void)
{
	struct timespec tv;
	clock_gettime(CLOCK_REALTIME, &tv);
	return tv.tv_sec + tv.tv_nsec * 1.0e-9;
}

int main()
{
	int i, j;
	double t1, t2;
	t1 = tstamp();

	/* version 1 */

	// for(i=0;i<N;i++) for(j=0;j<N;j++)
	//	t[i][j] = 1;

	/* version 2 */

	for (i = 0; i < N; i++)
		for (j = 0; j < N; j++)
			t[j][i] = 1;
	//
	t2 = tstamp();
	printf("time = %lf\n", t2 - t1);
	return 0;
}