old/sensors/imu_microstrain/clock_test.cpp File Reference

#include <stdio.h>
#include <time.h>
#include <math.h>
#include <sys/time.h>

Include dependency graph for old/sensors/imu_microstrain/clock_test.cpp:

Functions
int	frequency_of_primes (int n)
int	timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y)
float	elapsed_time (struct timeval dif, struct timeval a, struct timeval b)
int	main ()

Function Documentation

int frequency_of_primes

(

int

n

)

                                {
  int i,j;
  int freq=n-1;
  for (i=2; i<=n; ++i) for (j=sqrt(i);j>1;--j) if (i%j==0) {--freq; break;}
  return freq;
}

int timeval_subtract	(	struct timeval *	result,
		struct timeval *	x,
		struct timeval *	y
	)

{
  /* Perform the carry for the later subtraction by updating y. */
  if (x->tv_usec < y->tv_usec) {
    int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
    y->tv_usec -= 1000000 * nsec;
    y->tv_sec += nsec;
  }
  if (x->tv_usec - y->tv_usec > 1000000) {
    int nsec = (y->tv_usec - x->tv_usec) / 1000000;
    y->tv_usec += 1000000 * nsec;
    y->tv_sec -= nsec;
  }

  /* Compute the time remaining to wait.
     tv_usec is certainly positive. */
  result->tv_sec = x->tv_sec - y->tv_sec;
  result->tv_usec = x->tv_usec - y->tv_usec;

  /* Return 1 if result is negative. */
  return x->tv_sec < y->tv_sec;
}

float elapsed_time	(	struct timeval	dif,
		struct timeval	a,
		struct timeval	b
	)

{
/*Subtract the timevals*/ 
timeval_subtract(&dif,&a,&b);

/* Calculate and return difference in milliseconds */
return -dif.tv_sec*1000.0-dif.tv_usec/1000.0;
}

int main

(

)

{
  int f;
  int ti,tf,dt;
  printf ("Calculating...\n");

  struct itimerval *v;
  struct itimerval *ov=NULL;

  struct timeval tv1,tv2,diff;
  struct timezone tz;
  struct tm *tm;
  
  float k;
    
  ti = clock();
  //setitimer(ITIMER_REAL,v, ov);
  gettimeofday(&tv1, &tz);
  f = frequency_of_primes (9000);
  gettimeofday(&tv2, &tz);
  //getitimer(ITIMER_REAL,v);
  tf = clock();
  
  tm=localtime(&tv1.tv_sec);
  printf(" %d:%02d:%02d %d \n", tm->tm_hour, tm->tm_min,
  tm->tm_sec, tv1.tv_usec);

  tm=localtime(&tv2.tv_sec);
  printf(" %d:%02d:%02d %d \n", tm->tm_hour, tm->tm_min,
  tm->tm_sec, tv2.tv_usec);
  
  //timeval_subtract(&diff, &tv1, &tv2);
  k = elapsed_time(diff, tv1, tv2); 
  
  //printf("It took me %d microseconds...\n", -diff.tv_sec*1000000-diff.tv_usec);
  printf("It took me %f milliseconds\n", k);        
    //printf("It took me %d microseconds... \n", v.it_value.tv_usec);
    
    
  dt = tf - ti;
  printf ("The number of primes lower than 100,000 is: %d\n",f);
  printf ("It took me %d clicks (%f seconds). CPS: %ld\n",dt,dt/(double)CLOCKS_PER_SEC,(double)CLOCKS_PER_SEC);

  time_t seconds;

  time_t     now = time(0);
  //time_t  time;
  //time(&time)

  seconds = time (&now);
  printf ("%ld hours since January 1, 1970\n", seconds/3600);

  return 0;
}