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)::ptpt=1*ex_R4P+2*ey_R4P+3*ez_R4Pprint"(3(F3.1,1X))",abs(pt%x),abs(pt%y),abs(pt%z)endprogram volatile_doctest