[Cbc] segmentation fault using CBC trunk version in ClpPackedMatrix::scale during FPump

[Matthew Galati]

I am seeing this kind of error in several cases. This comes from my
framework calling Cbc using the CbcMain1 call. The problem is, when I dump
the .mps file I cannot repeat it running cbc directly. I even tried using
writeMpsNative with formatType=2, but it still would not repeat. I ran
through gdb to show the following. Any help would be greatly appreciated.
This is happening on several problems (using trunk).



D-ALGO   : 149      [CPU: 148     ] <--- printCurrentProblem() ---
calling writeMps filename = PRICE_AND_CUT_subProb_CASH_COUNT2.n0.c0.p7.b2
calling writeLp  filename = PRICE_AND_CUT_subProb_CASH_COUNT2.n0.c0.p7.b2
D-ALGO   : 149      [CPU: 147.7   ]  --- printCurrentProblem() ---> funcT =
0.008
Coin Cbc and Clp Solver version 1.2trunk, build Nov  3 2009
command line - cbc -log 1 -allowableGap 0.0001 -solve -quit (default
strategy 1)
logLevel was changed from 1 to 1
allowableGap was changed from 1e-10 to 0.0001
Continuous objective value is 65833.1 - 0.01 seconds
Cgl0003I 0 fixed, 84 tightened bounds, 0 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 23 tightened bounds, 0 strengthened rows, 0 substitutions
Cgl0004I processed model has 124 rows, 160 columns (56 integer) and 1322
elements
Cbc0038I Pass   1: suminf.    0.00000 (0) obj. 333015 iterations 34
Cbc0038I Solution found of 333015
Cbc0038I Before mini branch and bound, 34 integers at bound fixed and 36
continuous
Cbc0038I Full problem 124 rows 160 columns, reduced to 7 rows 15 columns
Cbc0038I Mini branch and bound improved solution from 333015 to 163670 (0.02
seconds)
Cbc0038I Freeing continuous variables gives a solution of 154514
Cbc0038I Round again with cutoff of 145646

Program received signal SIGSEGV, Segmentation fault.
0x00000000006ada55 in ClpPackedMatrix::scale (this=0x147c3f80,
model=0x147ce970)
    at ../../../Clp/src/ClpPackedMatrix.cpp:3400
3400                  if (usefulColumn[iColumn]) {



(gdb) where
#0  0x00000000006ada55 in ClpPackedMatrix::scale (this=0x147c3f80,
model=0x147ce970)
    at ../../../Clp/src/ClpPackedMatrix.cpp:3400
#1  0x00000000006ed775 in ClpSimplex::createRim (this=0x147ce970, what=63,
    makeRowCopy=true, startFinishOptions=7) at
../../../Clp/src/ClpSimplex.cpp:3126
#2  0x0000000000709e9b in ClpSimplex::startup (this=0x147ce970,
ifValuesPass=0,
    startFinishOptions=7) at ../../../Clp/src/ClpSimplex.cpp:8057
#3  0x0000000000729190 in ClpSimplexDual::startupSolve (this=0x147ce970,
    ifValuesPass=0, saveDuals=0x0, startFinishOptions=7)
    at ../../../Clp/src/ClpSimplexDual.cpp:238
#4  0x00000000007299b9 in ClpSimplexDual::dual (this=0x147ce970,
ifValuesPass=0,
    startFinishOptions=7) at ../../../Clp/src/ClpSimplexDual.cpp:584
#5  0x00000000006e95d9 in ClpSimplex::dual (this=0x147ce970, ifValuesPass=0,
    startFinishOptions=7) at ../../../Clp/src/ClpSimplex.cpp:5155
#6  0x0000000000637192 in OsiClpSolverInterface::crunch (this=0x14906a90)
    at ../../../../Osi/src/OsiClp/OsiClpSolverInterface.cpp:6429
#7  0x000000000064f014 in OsiClpSolverInterface::resolve (this=0x14906a90)
    at ../../../../Osi/src/OsiClp/OsiClpSolverInterface.cpp:1072
#8  0x000000000059c41c in CbcHeuristicFPump::solution (this=0x146134d0,
    solutionValue=@0x7fff6bd95438, betterSolution=0x14502fa0)
    at ../../../Cbc/src/CbcHeuristicFPump.cpp:555
#9  0x00000000005c7caf in CbcModel::doHeuristicsAtRoot (this=0x144ba5a0,
    deleteHeuristicsAfterwards=0) at ../../../Cbc/src/CbcModel.cpp:12937
#10 0x00000000005ee5a5 in CbcModel::branchAndBound (this=0x144ba5a0,
doStatistics=0)
    at ../../../Cbc/src/CbcModel.cpp:1826
#11 0x00000000004def6b in CbcMain1 (argc=7, argv=0x7fff6bd9f0c0,
    model=@0x7fff6bd9ec10, callBack=0x4b7e0c <dummyCallBack>)
    at ../../../Cbc/src/CbcSolver.cpp:8212
#12 0x00000000004ec832 in CbcMain1 (argc=7, argv=0x7fff6bd9f0c0,
    model=@0x7fff6bd9ec10) at ../../../Cbc/src/CbcSolver.cpp:3104

(gdb) p iColumn
$1 = 1083360460

(gdb) p usefulColumn[iColumn]
Cannot access memory at address 0x550e132c
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