On Mon, 2011-07-04 at 18:20 +0400, Andrew Makhorin wrote: > > 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.
To add to this, COIN has an interface called OSI which can interface between GLPK and CLP (though this is a template class and may need some juggling). A small question, how large is the LP ? Because most of them GLPK can solve in my experience (especially LP s). > _______________________________________________ > Help-glpk mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/help-glpk -- Thank you M B Pradeep Kumar _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
