Nodes of different colours represent the following:
Solid arrows point from a file to a file which it depends on. A file
is dependent upon another if the latter must be compiled before the former
can be.
program volatile_doctestuse vecfor_R4Ptype(vector_R4P)::pt(1:2)pt(1)=ex_R4P+ey_R4P+ez_R4Ppt(2)=pt(1)+1print"(L1)",pt(1)/=pt(2)endprogram volatile_doctest