/******************************************************************************
* FILE: mem01.c
* DESCRIPTION:
*   Demonstrates effect of stride
* LAST REVISED: 2/15/99 Blaise Barney
******************************************************************************/
#include <stdio.h>
#include <sys/time.h>
#include <time.h>
#define ARRAY_SIZE	1000
#define	SEED		1995

float a[ARRAY_SIZE][ARRAY_SIZE], aa[ARRAY_SIZE][ARRAY_SIZE];
float b[ARRAY_SIZE][ARRAY_SIZE], bb[ARRAY_SIZE][ARRAY_SIZE];
float c[ARRAY_SIZE][ARRAY_SIZE], cc[ARRAY_SIZE][ARRAY_SIZE];
struct timeval start_time, end_time;

main()
{
   int i, j;
   initialize_data();
/*****************************************************************************/
/*				Stride 1000 Loop			     */
/*****************************************************************************/
   gettimeofday(&start_time, (struct timeval*)0);

    for(j=0;j<1000;j++)
       for(i=0;i<1000;i++)
          cc[i][j] = cc[i][j] + aa[i][j] * bb[i][j];

   gettimeofday(&end_time, (struct timeval*)0);  /* after time */
   printf("Execution time for the stride 1000 loop:\n");
   print_execution_times();
/*****************************************************************************/
/*				Stride 1 Loop				     */
/*****************************************************************************/
   gettimeofday(&start_time, (struct timeval*)0);

    for(i=0;i<1000;i++)
       for(j=0;j<1000;j++)
          c[i][j] = c[i][j] + a[i][j] * b[i][j];

   gettimeofday(&end_time, (struct timeval*)0);  /* after time */
   printf("Execution time for the stride 1  loop:\n");
   print_execution_times();
   finalize_data();
}

initialize_data()
{
   int i, j;
   srandom(SEED);
    for(i=0;i<1000;i++)
       for(j=0;j<1000;j++)
       {
          aa[i][j] = a[i][j] = (float) (random() % 100000);
          bb[i][j] = b[i][j] = (float) (random() % 100000);
          cc[i][j] = c[i][j] = (float) (random() % 100000);
       }
}

finalize_data()
{
   int i, j;
   FILE *fp, *fopen();

   fp = fopen("/dev/null", "w");
   i = random() % ARRAY_SIZE;
   j = random() % ARRAY_SIZE;
   fprintf(fp, "%f\n", a[i][j]);
   fprintf(fp, "%f\n", aa[i][j]);
   fclose(fp);
}

print_execution_times()
{
   int total_usecs;
   float total_time, total_flops;
   total_usecs = (end_time.tv_sec-start_time.tv_sec) * 1000000 +
         (end_time.tv_usec-start_time.tv_usec);
   printf("Total time was %.2f mSec and the ", ((float) total_usecs) / 1000.0);
   total_time = ((float) total_usecs) / 1000000.0;
   total_flops = (float) (ARRAY_SIZE * ARRAY_SIZE * 2);
   printf("total MFLOPS is %.2f\n\n", (total_flops / total_time) / 1000000.0);
}