Opened 8 years ago

Closed 8 months ago

#53 closed defect (migrated)

Missing pivotSequence_ initialization causes CBC crash

Reported by: dindy Owned by: somebody
Priority: major Milestone:
Component: component1 Version: 1.0
Keywords: Cc:

Description

Hello,

first of all this bug report started from this CBC one:

https://projects.coin-or.org/Cbc/ticket/115

I add that I tested with the latest CBC trunk, which uses CLP 1.14, and the problem is still there. After some debugging I think I traced down the problem to a missing pivotSequence_ initialization in ClpPrimalColumnSteepest::pivotColumn. Looking at other parts of the code it seems to me that setting pivotRow_ to -2 should mean that the pivot computation should be restarted, but this is not done in ClpPrimalColumnSteepest::pivotColumn. I tried adding a simple:

if (pivotRow < -1) pivotSequence_ = -1;

at the beginning of ClpPrimalColumnSteepest::pivotColumn, just after:

int pivotRow = model_->pivotRow();

and the bug has gone. BTW, I'm no expert in the simplex algorithm and the code is pretty complicated to me so I'm unsure if this is the best place to reset pivotSequence_.

Hope it helps, and thanks for the excellent software.

Bye,

Denis Sbragion

Change History (1)

comment:1 Changed 8 months ago by stefan

  • Resolution set to migrated
  • Status changed from new to closed

This ticket has been migrated to GitHub and will be resolved there: ​https://github.com/coin-or/Clp/issues/53

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