[Cbc] Possible CbcBranchDynamic.cpp BUG

[Haroldo Santos]

Hi Forrest,

Tested again and the bug is gone.

Thanks,

Haroldo

On Wed, Sep 7, 2011 at 11:07 AM, John Forrest
<john.forrest at fastercoin.com>wrote:

> Should be fixed in 2.7 and trunk
> On Fri, 2011-09-02 at 20:11 -0300, Haroldo Santos wrote:
> > Did more experiments to see when this bug occurs.
> >
> > To turn off all heuristics and cuts it makes it happens faster.
> >
> > This is an instance
> > http://www.decom.ufop.br/haroldo/files/sprint_hidden06.lp.gz
> > which is quickly solved by CPLEX and has optimal objective function
> > value   130.
> >
> > CBC crashes at this point:
> >
> > Cbc0010I After 1700 nodes, 656 on tree, 249 best solution, best
> > possible 99.390873 (139.08 seconds)
> > cbc: CbcBranchDynamic.cpp:551: virtual int
> > CbcBranchDynamicDecision::betterBranch(CbcBranchingObject*,
> > CbcBranchingObject*, double, int, double, int): Assertion `distance >=
> > 0.0' failed
> >
> >
> >
> >
> >
> >
> >
> >
> > On Wed, Aug 24, 2011 at 5:43 PM, Haroldo Santos
> > <haroldo.santos at gmail.com> wrote:
> >         Dear Forrest/CBC Developers,
> >
> >         There is this assertion failing  in :
> >         CbcBranchDynamic.cpp:551: virtual int
> >         CbcBranchDynamicDecision::betterBranch(CbcBranchingObject*,
> >         CbcBranchingObject*, double, int, double, int): Assertion
> >         `distance >= 0.0' failed.
> >
> >         when I'm solving this MIP:
> >         http://www.decom.ufop.br/haroldo/files/sprint_hidden04.lp.gz
> >
> >
> >         I did some debug and discover that this fails because at a
> >         given point of the search the distance is  -0.415667  .
> >
> >         Cbc0010I After 10000 nodes, 4845 on tree, 180 best solution,
> >         best possible 142.25 (1909.96 seconds)
> >         Cbc0010I After 10100 nodes, 4849 on tree, 180 best solution,
> >         best possible 142.25 (1919.14 seconds)
> >
> >         Tested in Linux with CBC 2.7 stable, default compilation
> >         options and no ThirdParty software included.
> >
> >         The stack trace at this point is:
> >         #0  0x00007ffff779c5cb in
> >         CbcBranchDynamicDecision::betterBranch (this=0xb3eee10,
> >         thisOne=
> >             0x12d60060, changeUp=0, numInfUp=205, changeDown=0,
> >         numInfDown=211) at CbcBranchDynamic.cpp:555
> >         #1  0x00007ffff784bf40 in CbcNode::chooseDynamicBranch
> >         (this=0x12d9a290, model=0x60dcd0,
> >             lastNode=0x12aa7510, numberPassesLeft=4) at
> >         CbcNode.cpp:3178
> >         #2  0x00007ffff783521c in CbcModel::chooseBranch
> >         (this=0x60dcd0, newNode=@0x7fffffff53a0,
> >             numberPassesLeft=5, oldNode=0x12aa7510, cuts=...,
> >         resolved=@0x7fffffff4d18, lastws=0x12e21f40,
> >             lowerBefore=0x12ac54b0, upperBefore=0x1396c2e0,
> >         branches=@0x7fffffff4b08) at CbcModel.cpp:12642
> >         #3  0x00007ffff783b052 in CbcModel::doOneNode (this=0x60dcd0,
> >         baseModel=0x60dcd0,
> >             node=@0x7fffffff5298, newNode=@0x7fffffff53a0) at
> >         CbcModel.cpp:14299
> >         #4  0x00007ffff78108f5 in CbcModel::branchAndBound
> >         (this=0x60dcd0, doStatistics=0)
> >             at CbcModel.cpp:3797
> >         #5  0x00007ffff7b7be8b in CbcMain1 (argc=11,
> >         argv=0x7fffffffdef8, model=...,
> >             callBack=0x7ffff7b67569 <dummyCallBack(CbcModel*, int)>)
> >         at CbcSolver.cpp:5589
> >         #6  0x00007ffff7b67bb5 in CbcMain1 (argc=11,
> >         argv=0x7fffffffdef8, model=...) at CbcSolver.cpp:1111
> >         #7  0x0000000000400f47 in main (argc=11, argv=0x7fffffffdef8)
> >         at CoinSolve.cpp:336
> >
> >         Cheers,
> >
> >         Haroldo
> >
> >         --
> >         =============================================================
> >         Haroldo Gambini Santos
> >         Computing Department - Universidade Federal de Ouro Preto -
> >         UFOP
> >         email: haroldo [at ] iceb.ufop.br
> >         home/research page: www.decom.ufop.br/haroldo/
> >
> >         "Computer science is no more about computers than astronomy
> >         is about telescopes." Edsger Dijkstra
> >
> >
> >
> >
> > --
> > =============================================================
> > Haroldo Gambini Santos
> > Computing Department - Universidade Federal de Ouro Preto - UFOP
> > email: haroldo [at ] iceb.ufop.br
> > home/research page: www.decom.ufop.br/haroldo/
> >
> > "Computer science is no more about computers than astronomy
> > is about telescopes." Edsger Dijkstra
> >
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-- 
=============================================================
Haroldo Gambini Santos
Computing Department - Universidade Federal de Ouro Preto - UFOP
email: haroldo [at ] iceb.ufop.br
home/research page: www.decom.ufop.br/haroldo/

"Computer science is no more about computers than astronomy
is about telescopes." Edsger Dijkstra
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