Dear glpk maintaners,
we have found an ilp formulation (file glpk.mps) on which
glpsol with default options finds a solution
(the produced output is in default.txt) and on which
advanced MIP solver doesn't find (output: intopt.txt).
Is it a bug of glpk or are we doing something wrong?
Best Regards,
Marco Lattuada
lpx_read_mps: reading problem data from `glpk.mps'...
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
lpx_read_mps: problem name not specified
lpx_read_mps: 1548 rows, 549 columns, 5619 non-zeros
lpx_read_mps: 549 integer columns, 506 of which are binary
lpx_read_mps: 5850 cards were read
lpx_simplex: original LP has 1548 rows, 549 columns, 5619 non-zeros
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
lpx_simplex: presolved LP has 1213 rows, 430 columns, 2738 non-zeros
lpx_adv_basis: size of triangular part = 1213
0: objval = 4.000000000e+00 infeas = 1.000000000e+00 (0)
200: objval = 7.000000000e+00 infeas = 4.245664009e-01 (0)
400: objval = 7.000000000e+00 infeas = 3.490438973e-02 (0)
600: objval = 8.000000000e+00 infeas = 1.211764706e-02 (0)
655: objval = 9.000000000e+00 infeas = 4.702121045e-18 (0)
OPTIMAL SOLUTION FOUND
Integer optimization begins...
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
Objective function is integral
+ 655: mip = not found yet >= -inf (1; 0)
+ 1088: mip = not found yet >= 9.000000000e+00 (132; 1)
+ 1231: mip = 1.800000000e+01 >= 9.000000000e+00 50.0% (188; 1)
+ 2382: mip = 1.800000000e+01 >= 9.000000000e+00 50.0% (168; 167)
+ 3526: mip = 1.800000000e+01 >= 9.000000000e+00 50.0% (77; 610)
+ 4263: mip = 1.800000000e+01 >= tree is empty 0.0% (0; 1065)
INTEGER OPTIMAL SOLUTION FOUND
Time used: 18.0 secs
Memory used: 2.1 Mb (2240832 bytes)
lpx_read_mps: reading problem data from `glpk.mps'...
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
lpx_read_mps: problem name not specified
lpx_read_mps: 1548 rows, 549 columns, 5619 non-zeros
lpx_read_mps: 549 integer columns, 506 of which are binary
lpx_read_mps: 5850 cards were read
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
dmp_create_pool: warning: debug mode enabled
PROBLEM HAS NO PRIMAL FEASIBLE SOLUTION
Time used: 0.0 secs
Memory used: 0.9 Mb (908120 bytes)
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