On Thu, 2013-08-29 at 17:41 +0100, Cherif Mouaouia Bouzid wrote: > Hello > > > Thank you for what you are doing. > > > I have a recurrent problem when solving mixed-integer LPs. > > > Attached are an LP file example and its corresponding Output file. > > Here is the glpsol's terminal output: > > GLPSOL: GLPK LP/MIP Solver, v4.45 > Parameter(s) specified in the command line: > --lp example.lp --output example.out > Reading problem data from `example.lp'... > example.lp:1282: warning: missing final end of line > 952 rows, 634 columns, 2536 non-zeros > 317 integer variables, all of which are binary > 1282 lines were read > GLPK Integer Optimizer, v4.45 > 952 rows, 634 columns, 2536 non-zeros > 317 integer variables, all of which are binary > Preprocessing... > 952 rows, 634 columns, 2536 non-zeros > 317 integer variables, all of which are binary > Scaling... > A: min|aij| = 1.000e+00 max|aij| = 4.134e+04 ratio = 4.134e+04 > GM: min|aij| = 1.655e-01 max|aij| = 6.043e+00 ratio = 3.652e+01 > EQ: min|aij| = 2.738e-02 max|aij| = 1.000e+00 ratio = 3.652e+01 > 2N: min|aij| = 3.027e-02 max|aij| = 1.262e+00 ratio = 4.167e+01 > Constructing initial basis... > Size of triangular part = 952 > Solving LP relaxation... > GLPK Simplex Optimizer, v4.45 > 952 rows, 634 columns, 2536 non-zeros > 0: obj = 6.675300000e+03 infeas = 2.794e+02 (0) > 500: obj = 9.252882224e+03 infeas = 1.295e+02 (0) > Error: unable to factorize the basis matrix (2) > Sorry, basis recovery procedure not implemented yet > glp_intopt: cannot solve LP relaxation > Time used: 0.0 secs > Memory used: 1.0 Mb (1026045 bytes) > Writing MIP solution to `example.out'... > > > > I'm using Ubuntu 12.04. > > Regards > > > -- > > Cherif, Algeria >
Please use the most recent version of glpk, which is 4.52; see http://ftp.gnu.org/gnu/glpk/ . There have been made some essential improvements in the basis factorization routines, and now glpsol solves your mip successfully: GLPSOL: GLPK LP/MIP Solver, v4.52 Parameter(s) specified in the command line: --lp example.lp --log example.log Reading problem data from 'example.lp'... example.lp:1282: warning: missing final end of line 952 rows, 634 columns, 2536 non-zeros 317 integer variables, all of which are binary 1282 lines were read GLPK Integer Optimizer, v4.53 952 rows, 634 columns, 2536 non-zeros 317 integer variables, all of which are binary Preprocessing... 952 rows, 634 columns, 2536 non-zeros 317 integer variables, all of which are binary Scaling... A: min|aij| = 1.000e+00 max|aij| = 4.134e+04 ratio = 4.134e+04 GM: min|aij| = 1.655e-01 max|aij| = 6.043e+00 ratio = 3.652e+01 EQ: min|aij| = 2.738e-02 max|aij| = 1.000e+00 ratio = 3.652e+01 2N: min|aij| = 1.514e-02 max|aij| = 1.240e+00 ratio = 8.194e+01 Constructing initial basis... Size of triangular part is 952 Solving LP relaxation... GLPK Simplex Optimizer, v4.53 952 rows, 634 columns, 2536 non-zeros 0: obj = 6.675300000e+03 infeas = 1.388e+02 (0) 500: obj = 8.180770197e+03 infeas = 7.211e+01 (0) * 634: obj = 1.185575775e+04 infeas = 0.000e+00 (0) * 957: obj = 7.589768643e+02 infeas = 0.000e+00 (0) OPTIMAL LP SOLUTION FOUND Integer optimization begins... + 957: mip = not found yet >= -inf (1; 0) + 1291: mip = not found yet >= 1.314220420e+03 (273; 0) + 1371: >>>>> 8.712560000e+03 >= 1.314220420e+03 84.9% (301; 0) + 1482: >>>>> 4.443280000e+03 >= 1.358039358e+03 69.4% (304; 6) + 1511: >>>>> 2.317350000e+03 >= 1.444905676e+03 37.6% (158; 164) + 1511: mip = 2.317350000e+03 >= tree is empty 0.0% (0; 619) INTEGER OPTIMAL SOLUTION FOUND Time used: 7.2 secs Memory used: 1.5 Mb (1615938 bytes) _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
