[Cgl] cgl, cpx, mir, error

[Ted Ralphs]

There is a call to getRowActivity() in CglMixedIntegerRounding2. In
OsiCpx, this call is implemented through a call to CPLEX, which
complains that there is no solution whenever you have not just finished
solving the loaded instance (which it looks like you have not. The other
cut generators seem only to use calls that require returning information
cached in the interface layer, so you don't get the error.

Cheers,

Ted

Matthew Galati wrote:
> Hi.
> 
> I am creating an OsiCpx object, populating a model, setting the primal solution, and then calling the MIR cut generator.
> 
> OsiSolverInterface * siCgl = new OsiLpSolverInterface();
> 
>   siCgl->loadProblem(*m_modelCore->M,
>                        &m_modelCore->colLB[0],
>                        &m_modelCore->colUB[0],
>                        m_app->m_model.objCoeff, 
>                        &m_modelCore->rowLB[0],
>                        &m_modelCore->rowUB[0]);
> 
>    siCgl->setInteger(&m_modelRelax->integerVars[0],
>                       static_cast<int>(m_modelRelax->integerVars.size()));
>    siCgl->setColSolution(m_xhat);
> 
>    CglMixedIntegerRounding2 cglMirs;
>    cglMirs.generateCuts(*siCgl, cs);
> 
> And, I get the error from Cplex:
>   CPLEX Error  1217: No solution exists.
> 
> Note: I don't get that error with Cliques/Knap/Flow CGLs.
> 
> Any ideas?
> 
> Thanks,
> Matt
> 
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-- 
Dr. Ted Ralphs
Associate Professor
Industrial and Systems Engineering
Lehigh University
(610)758-4784
tkralphs at lehigh.edu
www.lehigh.edu/~tkr2