[Cbc] Infeasible for CBC (current stable), Value for CPLEX

[Christoph Cullmann]

On Tuesday, March 01, 2011 05:39:36 pm John Forrest wrote:
> Fixed in  trunk.
> 
> Took some time before I worked out ClpPresolve already had fix. Fixed
> OsiPresolve.
> 
> If presolve changes some integer bounds it goes round again on original
> model to see if it can do better.  If there are duplicate integer
> columns this can lead to a bug in extreme cases.
> 
> John Forrest
Thanks at lot!
My regression test suite works now again ;)

But next problem arises (not sure if that worked ever before, is a new ILP).

For the ILP here:

http://www.absint.com/dla/lp_solver_tests/value_9981169622464.lp

the correct result should be 9981169622464 but a simple 

    OsiClpSolverInterface solver;
    solver.readLp(infile);

    /**
     * Create CglPreProcessor
     */
    CglPreProcess process;
    process.passInMessageHandler (&messageHandler);

    /**
     * do pre process
     */
    OsiSolverInterface *preprocessedSolver = process.preProcess (solver);

    /**
     * resolve
     */
    preprocessedSolver->resolve();

    /**
     * initial solve
     */
    preprocessedSolver->initialSolve();

    /**
     * Cbc model creation
     */
    CbcModel model (*preprocessedSolver);
    model.passInMessageHandler (&messageHandler);

    /**
     * add some defaults
     */
    CbcMain0 (model);

    /**
     * add default strategy
     */
    CbcStrategyDefault strategy (true, 5, 5);
    model.setStrategy(strategy);

    /**
     * initial solve
     */
    model.branchAndBound();

leads to 463303730967 but claims that is the optimal solution ;)

Greetings
Christoph


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