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\Problem name:
Minimize
obj: x0 + 1000 x37 + 1000 x39 + 1000 x41
Subject To
cons0: x8 + x7 + x6 + x5 + x4 + x3 + x2 = 1
cons1: x16 - x9 + x2 = 0.20000
cons2: x17 - x10 + x3 = 0.20000
cons3: x18 - x11 + x4 = 0
cons4: x19 - x12 + x5 = 0
cons5: x20 - x13 + x6 = 0.20000
cons6: x21 - x14 + x7 = 0.20000
cons7: x22 - x15 + x8 = 0.20000
cons8: x15 + x14 + x13 + x12 + x11 + x10 + x9 <= 0.30000
cons9: -0.11000 x23 + x9 <= 0
cons10: -0.10000 x24 + x10 <= 0
cons11: -0.07000 x25 + x11 <= 0
cons12: -0.11000 x26 + x12 <= 0
cons13: -0.20000 x27 + x13 <= 0
cons14: -0.10000 x28 + x14 <= 0
cons15: -0.10000 x29 + x15 <= 0
cons16: -0.03000 x23 + x9 >= 0
cons17: -0.04000 x24 + x10 >= 0
cons18: -0.04000 x25 + x11 >= 0
cons19: -0.03000 x26 + x12 >= 0
cons20: -0.03000 x27 + x13 >= 0
cons21: -0.03000 x28 + x14 >= 0
cons22: -0.03000 x29 + x15 >= 0
cons23: -0.20000 x30 + x16 <= 0
cons24: -0.15000 x31 + x17 <= 0
cons25: x18 <= 0
cons26: x19 <= 0
cons27: -0.10000 x34 + x20 <= 0
cons28: -0.15000 x35 + x21 <= 0
cons29: -0.20000 x36 + x22 <= 0
cons30: -0.02000 x30 + x16 >= 0
cons31: -0.02000 x31 + x17 >= 0
cons32: -0.04000 x32 + x18 >= 0
cons33: -0.04000 x33 + x19 >= 0
cons34: -0.04000 x34 + x20 >= 0
cons35: -0.04000 x35 + x21 >= 0
cons36: -0.04000 x36 + x22 >= 0
cons37: x30 + x23 <= 1
cons38: x31 + x24 <= 1
cons39: x32 + x25 <= 1
cons40: x33 + x26 <= 1
cons41: x34 + x27 <= 1
cons42: x35 + x28 <= 1
cons43: x36 + x29 <= 1
cons44: -0.06200 x8 -0.18540 x7 -0.07630 x6 -0.15240 x5 -0.05010 x4 -0.10960
x3 -0.12870 x2 + x1 = 0
cons45: - x38 + x37 -23.68996 x8 -47.33083 x7 -28.70518 x6 -17.31699 x5
-23.22589 x4 -43.40210 x3 -44.73947 x2 + x0
= -17.79535
cons46: - x40 + x39 -23.26162 x8 -47.53517 x7 -29.73217 x6 -17.84761 x5
-24.07235 x4 -44.79997 x3 -44.06478 x2 + x0
= -17.87572
cons47: - x36 - x35 + x34 - x33 - x32 + x31 + x30 + x29 + x28 - x27
+ x26 - x25 - x24 - x23 <= 5
cons48: - x42 + x41 -23.77039 x8 -47.26785 x7 -28.70818 x6 -17.30250 x5
-23.25395 x4 -43.42913 x3 -45.11888 x2 + x0
= -17.87071
cons49: - x36 - x35 + x34 - x33 - x32 + x31 - x30 + x29 + x28 - x27
+ x26 - x25 - x24 - x23 <= 4
Bounds
x0 Free
0.12552 <= x1 <= 0.12552
0 <= x23 <= 1
0 <= x24 <= 1
0 <= x25 <= 1
0 <= x26 <= 1
0 <= x27 <= 1
0 <= x28 <= 1
0 <= x29 <= 1
0 <= x30 <= 1
0 <= x31 <= 1
0 <= x32 <= 1
0 <= x33 <= 1
0 <= x34 <= 1
0 <= x35 <= 1
0 <= x36 <= 1
Integers
x23 x24 x25 x26 x27 x28 x29 x30 x31 x32
x33 x34 x35 x36
End
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