sample.dmx

c this is a sample file for a tiny network in DIMACS standard fromat
c every line beginning with 'c' is a comment and it is ignored
c
c the first non-comment line has to be the unique 'p' line in the file;
c on this line there must be the problem type (which is ignored in the
c sample Main), a three-char string, and the number of nodes and arcs
c
p min 4 4
c
c after the 'p' line there must be at most <number of nodes> lines starting
c with 'n' and containing a node name `i' and the supply of node i; note
c that node names go from 1 to <number of nodes>; nodes which are given no
c supply are assigned a default supply 0
c
n 1 3
n 4 -3
c
c other than 'n' lines, there can be 'a' lines which describe arcs: the
c description of an arc is composed of the starting and ending node, the
c lower and upper bound on the flow and the cost of the flow, and there
c *must* be *exactly* <number of arcs> 'a' lines; although in this example
c arc and node lines are separate, in general they can be mixed
c
a 1 2 0 2 3
a 2 3 0 2 1
a 3 4 0 2 1
a 1 4 0 2 2