[Cbc-tickets] [COIN-OR Branch-and-Cut MIP Solver] #110: Assertion failed in parallel Cbc session.

[COIN-OR Branch-and-Cut MIP Solver]

#110: Assertion failed in parallel Cbc session.
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Reporter:  tsliwins  |       Type:  defect             
  Status:  new       |   Priority:  critical           
 Version:  2.7       |   Keywords:  parallel time limit
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 Hello.

 First of all, Cbc is a great piece of software - Thank You.

 I have a problem running Cbc in parallel mode.

 Cbc run on dual core machine with two threads
 stops on assertion (when debugged):

 CbcThread.cpp:598: void CbcBaseModel::stopThreads(int): Assertion
 `children_[i].returnCode() == -1' failed.

 and 'segfaults' when cbc is compiled without debug info.

 Of course I don't know if the segfault is related to the assertion.

 The error is repeatable, but only if the 'seconds' parameter is used, i.e.
 I start the debugger with the command:

 gdb --args ./cbc  -threads 2 -sec 120 -import test99.mps -solve

 and run the program with the 'run' command of gdb.

 Cbc was compiled on Ubuntu 10.10 using default compiler gcc 4.4.5
 with the --enable-debug option.

 My computer is Intel core2 duo 2.4 GHz, 3GB RAM.

 The mps file is attached to this message.

 And below are the final lines before the assertion.

 Best regards,
 Tomasz Sliwinski


 bc0014I Cut generator 2 (Knapsack) - 0 row cuts average 0.0 elements, 0
 column cuts (0 active)  in 0.050 seconds - new frequency is -100
 Cbc0014I Cut generator 3 (Clique) - 0 row cuts average 0.0 elements, 0
 column cuts (0 active)  in 0.010 seconds - new frequency is -100
 Cbc0014I Cut generator 4 (MixedIntegerRounding2) - 0 row cuts average
 0.0 elements, 0 column cuts (0 active)  in 0.020 seconds - new frequency
 is -100
 Cbc0014I Cut generator 5 (FlowCover) - 0 row cuts average 0.0 elements,
 0 column cuts (0 active)  in 0.060 seconds - new frequency is -100
 Cbc0014I Cut generator 6 (TwoMirCuts) - 119 row cuts average 369.0
 elements, 0 column cuts (0 active)  in 0.470 seconds - new frequency is
 -100
 [New Thread 0x7ffff6e94700 (LWP 1966)]
 [New Thread 0x7ffff6693700 (LWP 1967)]
 Cbc0010I After 0 nodes, 1 on tree, -0.021250295 best solution, best
 possible -0.8845281 (43.19 seconds)
 cbc: CbcThread.cpp:598: void CbcBaseModel::stopThreads(int): Assertion
 `children_[i].returnCode() == -1' failed.

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Ticket URL: <https://projects.coin-or.org/Cbc/ticket/110>
COIN-OR Branch-and-Cut MIP Solver <http://projects.coin-or.org/Cbc>
An LP-based branch-and-cut MIP solver.