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Re: [Help-glpk] [What is the easiest way to use COIN LP as solver in GLP

From: glpk xypron
Subject: Re: [Help-glpk] [What is the easiest way to use COIN LP as solver in GLPK ?]
Date: Mon, 25 Jul 2011 21:16:15 +0200

Hello Nicolas,

using GLPK together with CLP should work out of the box using
COIN Open Solver Interace. Unfortunately there seems to be no
active support for the GLPK interface.

The following tickets were opened three years ago:
Postprocessing of GMPL models
Usage of deprecated GLPK library functions
Method CoinMpsIO::readGMPL fails for GMPL model files without data section
OsiSolverInterface::readGMPL() does not support keeping names

OsiGlpkSolverInterface.cpp and CoinMpsIO.cpp need rewriting.


I suggest you contact the COIN-OR mailing list.

Best regards


-------- Original-Nachricht --------
> Datum: Mon, 25 Jul 2011 13:46:08 +0200
> Betreff: Re: [Help-glpk] [What is the easiest way to use COIN LP      as      
> solver  in GLPK ?]

> Hi Andrew,
> It has been a while for the last message of this discussion because I had
> no time to test your solution.
> Today I try to solve my gmpl problem with coin by using some of the glpk
> methods you mentioned. 
> I succeed in generating the free mps file corresponding to my problem and
> then I call coin like : clp.exe -import Test.mps -solve -solution
> solution.txt
> Now, I want to get back the solution into my glpk objects : my problem is
> that the format of the output file generated by coin (solution.txt) does
> not match the format readable by glpk methods (glp_read_sol).
> Is there a direct way to achieve this or do I have to convert coin
> solution file into a new file format readable by glpk ?
> Nicolas
> -----Message d'origine-----
> Envoyé : lundi 4 juillet 2011 16:21
> Objet : Re: [Help-glpk] [What is the easiest way to use COIN LP as solver
> in GLPK ?]
> > I am using GLPK in C++ programs like :
> >         glp_prob *lp = glp_create_prob();
> >     glp_tran *tran = glp_mpl_alloc_wksp();
> > 
> >     glp_mpl_read_model(tran, "..\\MyModel.mod", 1); 
> >     glp_mpl_read_data(tran, "..\\MyModel.dat");
> >     glp_mpl_generate(tran, NULL);
> >     glp_mpl_build_prob(tran, lp);
> >     glp_simplex(lp, NULL);
> >     glp_mpl_postsolve(tran, lp, GLP_MIP);
> > 
> >         glp_create_index(lp);
> >         int index = glp_find_col(lp, "MyVariable");
> >         double optimalValue = glp_get_row_prim(lp, index);
> >         
> > When using with big input data, the solving time becomes very 
> > important. So, I would like to use another solver like CLP. For 
> > example, in the above source, it would replace the ligne 
> > "glp_simplex(lp, NULL);" by the call of the new solver.
> > 
> > I found references for Symphony or Osi but I did not find clear 
> > examples doing what I am looking for.
> > Maybe, someone have met this problem or you could have valuable 
> > advices or suggestions that I could test...
> AFAIK, both Coin and Symphony allow using the glpk model translator.
> Another way is to output the mip data into a file, say, in free mps
> format, call an external solver, and load the solution back into the glpk 
> problem
> object. To simplify the interface between glpk and the external solver you
> may use api routines glp_write_prob, glp_read_mip, and glp_write_mip
> described in the glpk reference manual.
> If the external solver has its own api, you also may write an interface
> module; see an example attached.
> GDF SUEZ Mail Disclaimer:
> _______________________________________________
> Help-glpk mailing list
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