[Cbc] [CBC] gomory makes problem infeasible (even in version 2.9.5)

mg giunto.cardanico at gmail.com
Fri Jul 24 03:29:50 EDT 2015


Hi All,
if I remember correctly in version 2.9.4, gomory cuts generator started to
give some problems causing false infeasibilities. In theory, version 2.9.5
contains some fixes for this issue, but I think it's not completely
corrected since I've found a model that appears infeasible unless you
disable gomory cuts.

Attached you can find the LP file. Please note that I'm running this model
through callCbc(), and you need to disable heuristics otherwise
DiveCoefficient will find a solution before gomory cuts "too much"..

Here's a piece of code to reproduce the problem :

OsiClpSolverInterface solver;
CbcModel model(solver);
model.solver()->readLp("infeas.lp");
std::string args("-heur off -solve"); // using "-gomory off -solve" it works
callCbc(args, model);

Thanks in advance,
Marco
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