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OpenMP parallel for loop, bigIntegers

Is it possible to make a parallel for a loop whose index is not integer? I am using bigIntegers (new object).

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The OpenMP 4.0 specification was finalized and published a year ago. It provides that a parallel loop variable must have an integer or unsigned type, or a type or a random access pointer type or type (§2.6, p. 51).



So, basically no, it's impossible to create parallel for-loops with any type of variable.

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You can implement the planning yourself. Below is an example of using the equivalent schedule(static)

with GCC's built-in 128-bit targets.

#pragma omp parallel
{
    __int128 start = omp_get_thread_num()*N/omp_get_num_threads();
    __int128 finish = (omp_get_thread_num()+1)*N/omp_get_num_threads();
    for(__int128 i=start; i<finish; i++) foo(i);
}


If you want an equivalent schedule(dynamic)

you can do

__int128 cnt = 0;
#pragma omp parallel
for(__int128 i=0;;) {
    #pragma omp atomic capture
    i = cnt++;
    if(i>=N) break;
    foo(i);                                    
}
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