Hello Daniele, * The routine ios_relative_gap computes the relative mip gap using the * formula: * * gap = |best_mip - best_bnd| / (|best_mip| + DBL_EPSILON)
Minimization example: - Best integer solution 2 - Best bound -1.3 => Gap = (2 - -1.3) / 2 = 1.65 If you called glpsol --mipgap 1.7 -m problem.mod the solver would stop with this soution. Beware: The mip gap may rise while you solution gets better: Integer optimization begins... + 213: mip = not found yet <= +inf (1; 0) + 481: >>>>> -4.000000000e+00 <= 7.000000000e+00 275.0% (10; 0) + 875: >>>>> -3.000000000e+00 <= 2.600000000e+00 186.7% (15; 3) + 1215: >>>>> -1.000000000e+00 <= 1.000000000e+00 200.0% (15; 11) + 1397: mip = -1.000000000e+00 <= tree is empty 0.0% (0; 47) INTEGER OPTIMAL SOLUTION FOUND The mip gap rose from 1.867 to 2. while the objective rose from -3 to -1 in this maximization problem. Best regards Xypron On 30.07.2012 16:22, Daniele Micarelli wrote: > hi > I wanted to know more precisely what is the command: *mipgap tol* > > > and the number that goes in place of tol to indicate precisely what is? > > thank you very much > > > _______________________________________________ > Help-glpk mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/help-glpk
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