Hello Andrew, I guess what is missing either in function glp_ios_heur_sol() or in ios_feas_pump() is to solve the original problem with the integer values found.
I would prefer glp_ios_heur_sol to call glp_simplex. This would allow to check the feasibility of the heuristic solution and to provide local optimality. Best regards Xypron xypron wrote: > > Hello Andrew, > > I have solved the model below with > glpsol.exe --fpump -m test.mod --tmlim 30 > > (derived from > http://lists.gnu.org/archive/html/help-glpk/2009-09/msg00015.html > http://lists.gnu.org/archive/html/help-glpk/2009-09/msg00015.html > ) > > The output was > + 1763: mip = 1.041490000e+002 <= 1.200000000e+002 15.2% (2; 0) > TIME LIMIT EXCEEDED; SEARCH TERMINATED > ... > incommon[2,3] = 0.148999999999954 > ... > gamepair[2,3,4] = 1 > > sum{}incommon is to be maximized. > The only contraint limiting requires > incommon[i, j] <= sum{r in rounds}roundGame[r,i,j] > + sum{k in teams: i != k and j != k} gamepair[i, j, k]; > > roundGame is binary. Hence I would have expected a solution with > incommon[2,3] = 1 if gamepair[2,3,4] = 1. > > I would not have expected a MIP solution to yield an noninteger objective > for this model. > > This strange behaviour only occurs if the feasibility pump is used. > Could it be that it adds some cut that is not part of the original > problem? > > Best regards > > Xypron > > -- View this message in context: http://www.nabble.com/GLPSOL-outputs-MIP-solution-that-is-not-LP-optimal-for-fixed-integers-tp25337983p25340395.html Sent from the Gnu - GLPK - Bugs mailing list archive at Nabble.com. _______________________________________________ Bug-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-glpk
