OpenMP stochastic simulation

[martin]

BTW, not having 64bit unsigned integer numbers with well defined overflow behaviour makes it difficult to implement well-established random number generators in fortran. There are a couple generators which support split and merge operations, which helps to avoid any syncronisation within a parallel region. gfortran implements the xoshiro256** generator and its “jump” function for splitting (see libgfortran/intrinsics/random.c of in its current source tree). But I do not see how that is actually used by the compiler in conjunction with openmp code.