thread_vec.cc

//------------------------------------------------------------------------
#include <stdio.h>
#include <vector>
#include <time.h>
//------------------------------------------------------------------------
const int N_THREADS = 16;
//------------------------------------------------------------------------
int
func1(int n, int i){
  int sum = 0;
  for(int k=0;k<2;k++){
    std::vector <int> v;
    for(int j=0;j<n;j++){
      v.push_back(j*i); 
    }
    sum = sum + v[n/2];
  }
  return sum;
}
//------------------------------------------------------------------------
int
main(void){
  clock_t t1,t2;
  t1 = clock();
  #pragma omp parallel for schedule(static)
  for(int i=0;i<N_THREADS;i++){
    func1(10000000,i);
  }
  #pragma omp barrier
  t2 = clock();
  printf("Parallel %d\n",t2-t1);
  t1 = clock();
  func1(10000000,0);
  t2 = clock();
  printf("Serial   %d\n",t2-t1);
}
//------------------------------------------------------------------------