Hello, you will have remarked that glpsol outputs: PROBLEM HAS NO DUAL FEASIBLE SOLUTION because any unbounded value of x_16 will solve the problem.
If you add constraints for x_16 you will get the expected result, e.g. var x_1; var x_2; var x_3; var x_4; var x_5; var x_6; var x_7; var x_8; var x_9; var x_10; var x_11; var x_12; var x_13; var x_14; var x_15; var x_16, <= 1, >=0; minimize objective: + 6 * x_1 + x_2 + x_3 + 5 * x_4 + 2 * x_5 + 7 * x_6 + 7 * x_7 + 6 * x_8 + 3 * x_9 + 3 * x_10 + 7 * x_11 + 8 * x_12 + 8 * x_13 + 2 * x_14 + 5 * x_15; s.t. constraint1: + x_1 = 1; s.t. constraint2: + x_2 = 1; s.t. constraint3: + x_3 = 1; s.t. constraint4: + x_4 = 1; s.t. constraint5: + x_5 = 1; s.t. constraint6: + x_6 = 1; s.t. constraint7: + x_7 + x_16 = 1; s.t. constraint8: + x_8 = 1; s.t. constraint9: + x_9 = 1; s.t. constraint10: + x_10 = 1; s.t. constraint11: + x_16 + x_11 = 1; s.t. constraint12: + x_16 + x_12 = 1; s.t. constraint13: + x_13 + x_16 = 1; s.t. constraint14: + x_14 = 1; s.t. constraint15: + x_15 = 1; solve; printf "x_7.dual=%f\n", x_7.dual; printf "x_11.dual=%f\n",x_11.dual; printf "x_12.dual=%f\n",x_12.dual; printf "x_13.dual=%f\n",x_13.dual; end; Best regards Xypron -------- Original-Nachricht -------- > Datum: Wed, 5 Oct 2011 12:28:46 +0200 > Betreff: [Help-glpk] dual values > Hello, > > I'm adding a column in a model and when I calculate the dual values I got > wrong results > > Minimize > objective: + 6 x_1 + x_2 + x_3 + 5 x_4 + 2 x_5 + 7 x_6 + 7 x_7 + 6 x_8 > + 3 x_9 + 3 x_10 + 7 x_11 + 8 x_12 + 8 x_13 + 2 x_14 + 5 x_15 > > Subject To > constraint1: + x_1 = 1 > constraint2: + x_2 = 1 > constraint3: + x_3 = 1 > constraint4: + x_4 = 1 > constraint5: + x_5 = 1 > constraint6: + x_6 = 1 > constraint7: + x_7 + x_16 = 1 > constraint8: + x_8 = 1 > constraint9: + x_9 = 1 > constraint10: + x_10 = 1 > constraint11: + x_16 + x_11 = 1 > constraint12: + x_16 + x_12 = 1 > constraint13: + x_13 + x_16 = 1 > constraint14: + x_14 = 1 > constraint15: + x_15 = 1 > > End > > I have added x-16. > Shouldn't the dual for the variables x_7, x_11 , x_12 and x_13 be equal to > 0 > ? > > Thank you > > Onor -- Follow me at http://twitter.com/#!/xypron Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
