Hello Andrew, I would like to set the integer values of a possible solution in glpsol such that this solution is used as a starting point for the branch and cut solver. I do not want to preset the non integer values.
I have patched glpk-4.34 such that variable values can be preset, e.g. var x := 4; The changed files and diffs can be downloaded from http://glpk.dyndns.org/viewvc/svn/glpk/glpk/branches/glpk-4.34-dot/ Changes (including changes for outputting dual values) are in include/glpmpl.h src/glpapi16.c (only changes for output of dual values) src/glpmpl01.c src/glpmpl03.c src/glpmpl04.c (only changes for output of dual values) What is missing, are the necessary changes to glpsol (glpapi17.c). Would this be a correct implementation: Create a callback routine. Pass it as parm.cb_func to glp_intopt. In the callback routine react to the first call with reason GLP_IHEUR as follows: - Preset the integer variables in tree->mip. - Initialize parameters: glp_init_smcp(&parm); - Set parameters: parm.meth = GLP_DUALP; - Solve the LP: ret = glp_simplex(tree->mip, &parm); - Pass all variables with a call to glp_ios_heur_sol. Is this a feature you would be willing to integrate into the distribution? Best regards Xypron -- View this message in context: http://www.nabble.com/Setting-initial-integer-solution-in-GLPSOL-tp21005682p21005682.html Sent from the Gnu - GLPK - Help mailing list archive at Nabble.com. _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
