OpenMP* worksharing construct not in parallel region

A worksharing construct appears in a context where it will not execute in parallel.

An OpenMP* worksharing construct defines a collection of units of work that could be executed in parallel. However, the presence of a worksharing construct alone does not create a team of threads that will execute those units of work in parallel. Rather, a worksharing region binds to the innermost enclosing PARALLEL region. This error indicates that this worksharing construct is not (or not always) dynamically enclosed within a PARALLEL region and, therefore, will (or may) not execute in parallel.

The most straightforward fix is to replace the worksharing construct with a parallel worksharing construct. For example, instead of "#pragma omp for" (for C) or "!$OMP DO" (for FORTRAN), use "#pragma omp parallel for" or "!$OMP PARALLEL DO".

ID	Code Location	Description
1	OpenMP declaration	The location of the worksharing construct

Example


void f(int n, double *a1, double *a2, double *a3)
{
    int i;
    // should be #pragma omp parallel for unless called from a parallel region
    #pragma omp for 
    for (i = 1; i++; i < n) {
        a1[i] = a2[i] * a3[i];
    }
}

Here is the same example in FORTRAN:


subroutine F(N, A1, A2, A3)
    integer N, I
    real A1(N), A2(N), A3(N)
    ! Should be $OMP PARALLEL DO if not called from parallel region
    !$OMP DO
    do I = 1, N
        A1[I] = A2[I] * A3[I]
    end do
    !$OMP END DO
end subroutine F