[Cbc] "Index out of bounds" when pre-processing problems with SOSes

[Dirk Eßer]

Hi John,

the driver attached to this mail fails (when fed the "test3.mps") with 
the following stacktrace:

    #0 0x00007ffff4c43849 in raise () from /lib64/libc.so.6
    #1  0x00007ffff4c44cd8 in abort () from /lib64/libc.so.6
    #2  0x00007ffff553c655 in __gnu_cxx::__verbose_terminate_handler()
    () from /usr/lib64/libstdc++.so.6
    #3  0x00007ffff553a7c6 in ?? () from /usr/lib64/libstdc++.so.6
    #4  0x00007ffff553a7f3 in std::terminate() () from
    /usr/lib64/libstdc++.so.6
    #5  0x00007ffff553aa1e in __cxa_throw () from /usr/lib64/libstdc++.so.6
    #6  0x00007ffff6c77185 in indexError (index=2,
    methodName="isInteger") at OsiClpSolverInterface.cpp:1447
    #7  0x00007ffff6c7d02f in OsiClpSolverInterface::isInteger
    (this=0x64d5e0, colNumber=2) at OsiClpSolverInterface.cpp:2756
    #8  0x00007ffff7b86dd1 in CbcSOS::CbcSOS (this=0x629530,
    model=0x7fffffffd860, numberMembers=2, which=0x64ce90,
    weights=0x6488b0, identifier=0, type=1) at CbcSOS.cpp:67
    #9  0x00007ffff7b4e0a0 in CbcModel::findIntegers
    (this=0x7fffffffd860, startAgain=false, type=0) at CbcModel.cpp:10949
    #10 0x00007ffff7b28f30 in CbcModel::branchAndBound
    (this=0x7fffffffd860, doStatistics=0) at CbcModel.cpp:1920
    #11 0x0000000000403e4e in main (argc=1, argv=0x7fffffffde88) at
    user_driver.cpp:328

on

    SMP x86_64 x86_64 x86_64 GNU/Linux
    g++ (SUSE Linux) 4.8.1 20130909 [gcc-4_8-branch revision 202388]
    compiled against 2.8 of the CBC library

We also observe this behaviour from within our main application, which 
creates the problem instance programmatically (but whose actual 
processing step is pretty close to what the driver does). Inspecting the 
variables in frame #7, we find, that the number of columns is reported 
to be 0. I am not sure, how this should be interpreted...

There was a similar problem with integer declarations (which we formerly 
did by adding OsiSimpleInteger objects), where the program triggered an 
assertion from time to time. After switching the declaration code to 
calls to "setInteger" on the "OsiClpSolverInterface", that problem went 
away. Not sure, whether it was related; IIRC, when this tended to 
happen, the reported column count after pre-processing was not 0.

Any help appreciated.

Dirk


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