Nodes of different colours represent the following:
Solid arrows point from a procedure to one which it calls. Dashed
arrows point from an interface to procedures which implement that interface.
This could include the module procedures in a generic interface or the
implementation in a submodule of an interface in a parent module.
function get_rng()result(r)type(rng_type)::rinteger::thread_id#ifdef _OMPthread_id=OMP_get_thread_num()+1#elsethread_id=1#endifr=rng(thread_id)end function get_rng