Encapsulate OpenMP pragma to avoid compilation errors

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Problem description

To avoid having a compilation error, it is necessary to encapsulate the OPENMP pragma to avoid compilation errors when not setting the openmp option (-fopenmp with gcc)

Reproducible example code

#ifdef _OPENMP
    #pragma omp parallel for collapse(2)
#endif

added Compilation ⚙ label

assigned to @mick94

changed title from Encapsuler les pragma OPENMP pour éviter les erreurs de compilation to Encapsulate OpenMP pragma to avoid compilation errors

added Good First Issue label

mentioned in merge request !33 (closed)

mentioned in merge request !40 (merged)

Done in !40 (merged).

closed