[Cbc] failure in small IP

[Matthew Galati]

The following small IP fails using the CbcMain1 interface. It is a unique case, because all rows and cols are removed by presolver.

http://coral.ie.lehigh.edu/~magh/tmp/subProb.n0.c0.p1.b0.lp

https://projects.coin-or.org/Cbc/ticket/79

          CbcModel cbc(*subprobSI);
          CbcMain0(cbc);
          const char * argv[] = {"cbc","-solve","-quit"};
          CbcMain1(3, argv, cbc);

Coin Cbc and Clp Solver version 1.2trunk, build Sep  9 2009
command line - cbc -solve -quit (default strategy 1)
Continuous objective value is 46.6667 - 0.00 seconds
Cgl0003I 20 fixed, 0 tightened bounds, 0 strengthened rows, 0 substitutions
Cgl0003I 5 fixed, 0 tightened bounds, 0 strengthened rows, 8 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 0 strengthened rows, 8 substitutions
Cgl0004I processed model has 0 rows, 0 columns (0 integer) and 0 elements

gdb gives:

Program received signal SIGSEGV, Segmentation fault.
0x0000003ffa871f6b in free () from /lib64/libc.so.6
(gdb) where
#0  0x0000003ffa871f6b in free () from /lib64/libc.so.6
#1  0x000000000057bc41 in ~CbcRounding (this=0x7fffec90c080)
    at ../../../Cbc/src/CbcHeuristic.cpp:1552
#2  0x00000000004ae837 in doHeuristics (model=0x1d1f3e00, type=1)
    at ../../../Cbc/src/CbcSolver.cpp:3479
#3  0x00000000004c7776 in CbcMain1 (argc=3, argv=0x7fffec9150c0,
    model=@0x7fffec914bb0, callBack=0x4a734c <dummyCallBack>)
    at ../../../Cbc/src/CbcSolver.cpp:6680
#4  0x00000000004db968 in CbcMain1 (argc=3, argv=0x7fffec9150c0,
    model=@0x7fffec914bb0) at ../../../Cbc/src/CbcSolver.cpp:3099



Note, if I run it from the command line using cbc executable, the error does not occur.

[magala at orclus71 MMKP]$ ~/COIN/coin-Cbc/build-g/bin/cbc subProb.n0.c0.p1.b0.lp
Coin Cbc and Clp Solver version 1.2trunk, build May 27 2009
command line - /users/magala/COIN/coin-Cbc/build-g/bin/cbc subProb.n0.c0.p1.b0.lp (default strategy 1)
Continuous objective value is 46.6667 - 0.00 seconds
Cgl0003I 20 fixed, 0 tightened bounds, 0 strengthened rows, 0 substitutions
Cgl0003I 5 fixed, 0 tightened bounds, 0 strengthened rows, 8 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 0 strengthened rows, 8 substitutions
Cgl0004I processed model has 0 rows, 0 columns (0 integer) and 0 elements
Cbc3007W No integer variables - nothing to do
Cuts at root node changed objective from 46.6667 to -1.79769e+308
Probing was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Gomory was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Knapsack was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Clique was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
MixedIntegerRounding2 was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
FlowCover was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
TwoMirCuts was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Result - Finished objective 46.66667 after 0 nodes and 0 iterations - took 0.00 seconds (total time 0.01)
Total time 0.01
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