[Coin-discuss] sychronising the solution for OsiCbc after branch and bound

[Kish Shen]

Hi,

I have been trying to improve the performance of the MIP search while using 
the OsiCbcSolverInterface. Instead of just calling the branchAndBound() 
method, I tried to use the code from the sample2.cpp example in Cbc's Sample 
directory. 

I can see from the message that the MIP search seem to work correctly, but 
trying to access the solution state via OsiCbcSolverInterface does not work. 
I think this is because the sample2 code clones the solver before doing the 
search. 

I tried to do a dynamic cast (as John suggested in answer to another post of 
mine):

	model.branchAndBound();
	lpd->lp->Solver = dynamic_cast< OsiCbcSolverInterface*>(model.solver());

where model is a CbcModel, and lpd->lp->Solver is a OsiCbcSolverInterface *. 
This however seg faults as soon as I make the next call using lpd->lp->Solver. 
I assume this is because model.solver() is the clp solver, rather than Cbc? 
How should I set the state of lpd->lp->Solver to the model's?

I also need to preserve the reference solver of the original CbcModel pointer 
of lpd->lp->Solver, because I saved the original state of the problem before 
going into the branch and bound.

Thanks in advance for any help!

Cheers,

Kish Shen