Nodes of different colours represent the following:
Solid arrows point from a submodule to the (sub)module which it is
descended from. Dashed arrows point from a module or program unit to
modules which it uses.
program volatile_doctestuse vecfor_R4Ptype(vector_R4P)::ptpt=ex_R4P+ey_R4Pcall pt%normalizeprint"(3(F4.2,1X))",abs(pt%x),abs(pt%y),abs(pt%z)endprogram volatile_doctest