Multiple arcs with the same tail and head nodes are prohibited. PROC INTPOINT checks to ensure there are no such arcs before
proceeding with the optimization. Introduce a new dummy intermediate node in multiple arcs. This node must be distinct for
each multiple arc. For example, if some network has three arcs directed from node A
toward node B
, then replace one of these three with arcs (A,C)
and (C,B)
and replace another one with (A,D)
and (D,B)
. C
and D
are new nodes added to the network.