double-check DRB172-parallel-orig-no.c

[chunhualiao]

This code is too complex. Please reduce it further. You don't need the same statements show up 15+ times in the loop. One or two may be sufficient.

Which variables cause the tools to report data races?

loop variables j and k are shared in this code, they may cause true posive data races.

only loop variable i immediately after "omp for" will be private by some implicit rule.

I am not sure this code is really data race free.

[xintin]

As pointed by @chunhualiao, there is an obvious data race. If we use private clause it can be fixed. We do have such examples already covered. So, I am excluding this.

Below is the simplified version of this program having the same functionality:

#include <stdio.h>
#include <omp.h>

int main(){
  int i,j,k,m;
  double tmp1;

  double a[12][12][12];

  m = 3.0;

  #pragma omp parallel for private(j,k,tmp1)          // use private(j,k,tmp1) to avoid data race
  for (i = 0; i < 12; i++) {
    for (j = 0; j < 12; j++) {
      for (k = 0; k < 12; k++) {
        tmp1 = 6.0/m;
        a[i][j][k] = tmp1+4;
      }
    }
  }

  printf("%f\n",a[i][j][k]);
  return 0;
}