#include <time.h>
#include <sys/resource.h>

double get_cpu_time()
{ struct rusage ruse;
  getrusage(RUSAGE_SELF, &ruse);
  return ruse.ru_utime.tv_sec + ruse.ru_utime.tv_usec / 1000000.0 + 
         ruse.ru_stime.tv_sec + ruse.ru_stime.tv_usec / 1000000.0; }