[Lemon-user] exception: divide by zero in v1.3 network simplex arc mixing

[Carlos Carroll]

When I run LEMON 1.3, I get an unhandled exception due to division by zero
in the following code (line 940) from network_simplex.h

if (_arc_mixing) {
        // Store the arcs in a mixed order
        const int skip = std::max(_arc_num / _node_num, 3);

When I set _arc_mixing to "false", the process runs without a problem.

I do not have nodes labeled 0 in my input lgf, so not sure where this
problem (_node_num = 0) originates.
The comments in the file suggest that turning off arc mixing may result in
slower processing times and other drawbacks.
Is this a bug, and are there better workarounds than turning off arc mixing?
Thanks.
_____

Carlos Carroll, Ph.D.
Klamath Center for Conservation Research 
PO Box 104 
Orleans, CA 95556