[Cbc] How to add cuts?

[Haroldo Gambini Santos]

Hi,

You should specialize a  CglCutGenerator class to implement cut generation.

Then you need to implement:
generateCuts( const OsiSolverInterface &si, OsiCuts &cs, const 
CglTreeInfo info )

Use /si/ to obtain the fractional solution and add discovered cuts in /cs/.

Cheers,

Haroldo

Em 13-03-2016 22:07, 不入角蜗牛 escreveu:
> Hello.
> I try to use the class CbcEventHandler to add cuts to solve my 
> problem, but it doesn't work.
> for example :
> min: x2
> s.t. x0 + x1 >= 1;
>       x1 + x2 >= 1;
> x0,x1,x2 in {0,1}
> Add the question normally. I get x0 = 1, x1 = 1 and x2 = 0. But when I 
> try to add a cut x0 = 0 with codes:
> <\code
>         auto refSolver = model->referenceSolver();
>         CoinPackedVector solution_cut;
>         solution_cut.setVector(len, &cols[cols.size()-len], 
> &values[values.size()-len]);
>         refSolver->addRow(solution_cut, rhs_lower.back(), 
> rhs_upper.back());
>         model->resetToReferenceSolver();
> code\>
> But failed. I save the model as mps file and it can be read as:
>  TITLE BLANK;
>  [ OBJROW] MIN =  C0000002;
>  [ R0000000]  C0000000 +  C0000001 >= 1;
>  [ R0000001]  C0000001 +  C0000002 >= 1;
>  [ R0000002]  C0000000 = 0;
>  @BND( 0, C0000000, 0); @BND( 0, C0000001, 0);
>  @BND( 0, C0000002, 0);
> Thanks.
>
>
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-- 
==================================================
Haroldo Gambini Santos
D.Sc, Computer Science
Universidade Federal de Ouro Preto
http://www.decom.ufop.br/haroldo/

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