drtest

drtest.c

// profiling results: http://imgur.com/a/lIFSY
// compiled on osx like so:
// gcc -o drtest_no_optimization drtest.c -pg
// gcc -o drtest_with_ofast drtest.c -pg -Ofast
// gcc -o drtest_with_otwo drtest.c -pg -O2

#include <stdlib.h>
#include <time.h>
#include <math.h>

#define NUM_POINTS 100000000

double point1[NUM_POINTS], point2[NUM_POINTS], mid[NUM_POINTS];
int i;

void __attribute__ ((noinline)) divide_that_shit(void)
{
  for(i = 0; i < NUM_POINTS; i++)
  {
    mid[i] = (point1[i] + point2[i]) / 2.0;
  }
}

void __attribute__ ((noinline)) fabs_that_shit(void)
{
  for(i = 0; i < NUM_POINTS; i++)
  {
    mid[i] = fabs(point1[i] - point2[i]);
  }
}

int main(void)
{
  srand((unsigned)time(NULL));

  for(i = 0; i < NUM_POINTS; i++)
  {
    point1[i] = ((double)rand()/(double)RAND_MAX);
    point2[i] = ((double)rand()/(double)RAND_MAX);
  }

  divide_that_shit();

  fabs_that_shit();

  return 0;
}