[Coin-lpsolver] Assertion failed: nowUpper < large, file CoinPresolveImpliedFree.cpp, line 702

[Jean-Sebastien Roy]

Hi !

Trying Sbb on Solaris, i encountered a bug that I cannot reproduce under
Linux (see the log below). It's quite difficult to describe the
situation, so my report will probably not be helpful. Sorry !

I use the COIN_2004Mar16.tgz source and the test3.mps file attached.

I solve the continuous relaxation with Clp via OSI using
OsiDoPresolveInInitial and OsiDoDualInInitial (in a C++ code)
Then I solve the MIP using Sbb using all cuts (gomory, knapsack,
oddhole, probing) with the same defaults as in the command line sbb.
I use the integer presolve and the rounding heuristic on the presolved
model.

Regards,

js

Coin0506I Presolve 138 (-24) rows, 130 (-19) columns and 404 (-7) elements
Clp0014I Perturbing problem by 0.001 % of 2928.49 - largest nonzero
change 0.00955308 (% 0.0535659) - largest zero change 0.00576967
Clp0005I 0  Obj 1674.15 Primal inf 22.3208 (9) Dual inf 1593.88 (18)
Clp0005I 89  Obj 2547.15
Clp0000I Optimal - objective value 2546.96
Coin0511I After Postsolve, objective 2546.96, infeasibilities - dual 0
(0), primal 0 (0)
Clp0005I 0  Obj 2546.96
Clp0005I 0  Obj 2546.96
Clp0000I Optimal - objective value 2546.96
Sbb0013I At root node, 6 cuts changed objective from 2546.96 to 2623.96
in 3 passes
Sbb0014I Cut generator 0 (Gomory) - 25 row cuts (6 active), 0 column
cuts - new frequency is 1
Sbb0014I Cut generator 1 (Probing) - 0 row cuts (0 active), 0 column
cuts - new frequency is 10
Sbb0014I Cut generator 2 (Knapsack) - 0 row cuts (0 active), 0 column
cuts - new frequency is 100
Sbb0014I Cut generator 3 (OddHole) - 0 row cuts (0 active), 0 column
cuts - new frequency is 100
Sbb0010I After 0 nodes, 1 on tree, 1e+50 best solution, best possible
2623.96
Assertion failed: nowUpper < large, file CoinPresolveImpliedFree.cpp,
line 702


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