code for 1 thread

//
// helloflops1
//
// A simple example to try
// to get lots of Flops on
// Intel(r) Xeon Phi(tm) co-processors.
//

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
//
// dtime -
//
// utility routine to return
// the current wall clock time
//
double dtime()
{
    double tseconds = 0.0;
    struct timeval mytime;
    gettimeofday(&mytime,(struct timezone*)0);
    tseconds = (double)(mytime.tv_sec + mytime.tv_usec*1.0e-6);
    return( tseconds );
}


#define FLOPS_ARRAY_SIZE (1024*1024)
#define MAXFLOPS_ITERS 100000000
#define LOOP_COUNT 128
// Floating pt ops per inner loop iteration
#define FLOPSPERCALC 2
// define some arrays - 64 byte aligned for fastest cache access
float fa[FLOPS_ARRAY_SIZE] __attribute__((align(64)));
float fb[FLOPS_ARRAY_SIZE] __attribute__((align(64)));

//
// Main program - pedal to the metal...calculate tons o'flops!
//
int main(int argc, char *argv[] )
{
        int i,j,k;
        double tstart, tstop, ttime;
    double gflops = 0.0;
    float a=1.1;


        //
        // initialize the compute arrays
        //

        printf("Initializing\r\n");
        for(i=0; i<FLOPS_ARRAY_SIZE; i++)
        {
        fa[i] = (float)i + 0.1;
            fb[i] = (float)i + 0.2;
        }

        printf("Starting Compute\r\n");

        tstart = dtime();
        // loop many times to really get lots of calculations
        for(j=0; j<MAXFLOPS_ITERS; j++)
        {
        //
        // scale 1st array and add in the 2nd array
        // example usage - y = mx + b;
        //
            for(k=0; k<LOOP_COUNT; k++)
        {
                fa[k] = a * fa[k] + fb[k];
            }
     }
         tstop = dtime();

         // # of gigaflops we just calculated
         gflops = (double)( 1.0e-9*LOOP_COUNT*MAXFLOPS_ITERS*FLOPSPERCALC);

     // elasped time
         ttime = tstop - tstart;

         //
         // Print the results
         //
         if ((ttime) > 0.0)
         {
             printf("GFlops = %10.3lf, Secs = %10.3lf, GFlops per sec = %10.3lf\r\n",
                     gflops, ttime, gflops/ttime);
         }
         return( 0 );
}