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[Bug-glpk] xassert fail in MIR cut back substitution
From: |
Stefan Vigerske |
Subject: |
[Bug-glpk] xassert fail in MIR cut back substitution |
Date: |
Tue, 4 Dec 2007 23:19:56 +0300 |
Hi,
I have a MIP where an assertion in the new mir cut generation routines
in GLPK 4.24 is failing.
Find attached a cplex-lp file. I was able to produce the problem on a
linux 64bit machine, and it also appear on some other platforms, but not
on every, e.g., not on linux 32bit.
It should pop up with
./glpsol --cpxlp --intopt --cuts glpk_mirassertfail.lp
and the output is
lpx_read_cpxlp: reading problem data from `glpk_mirassertfail.lp'...
lpx_read_cpxlp: 50 rows, 43 columns, 169 non-zeros
lpx_read_cpxlp: 14 integer columns, all of which are binary
lpx_read_cpxlp: 81 lines were read
ipp_basic_tech: 6 row(s) and 5 column(s) removed
ipp_reduce_bnds: 3 pass(es) made, 26 bound(s) reduced
ipp_basic_tech: 0 row(s) and 0 column(s) removed
ipp_reduce_coef: 1 pass(es) made, 0 coefficient(s) reduced
lpx_intopt: presolved MIP has 44 rows, 38 columns, 152 non-zeros
lpx_intopt: 12 integer columns, all of which are binary
lpx_adv_basis: size of triangular part = 43
Solving LP relaxation...
0: objval = 2.543860150e+04 infeas = 1.000000000e+00 (0)
24: objval = 6.655303517e+04 infeas = 0.000000000e+00 (0)
* 24: objval = 6.655303517e+04 infeas = 0.000000000e+00 (0)
* 43: objval = 1.779541789e+01 infeas = 5.079270338e-16 (0)
OPTIMAL SOLUTION FOUND
Creating the conflict graph...
The conflict graph has 2*10 vertices and 15 edges
Generating cutting planes...
& 43: obj = 1.779541789e+01 frac = 3 cuts = 0 (0)
& 95: obj = 1.789692248e+01 frac = 1 cuts = 10 (198)
10 Gomory's mixed integer cut(s) added
Integer optimization begins...
+ 95: mip = not found yet >= -inf (1; 0)
MIR cuts enabled
ios_mir_init: warning: debug mode enabled
GLPK internal error: jj != 0; file glpios05.c, line 1087
(I had enabled _MIR_DEBUG for testing. The problem comes with or without
it.)
Best,
Stefan
glpk_mirassertfail.lp
Description: Text document
- [Bug-glpk] xassert fail in MIR cut back substitution,
Stefan Vigerske <=