[Cbc] Segmentation fault in release build revealed assertion failed in debug build
John Forrest
john.forrest at fastercoin.com
Tue Oct 23 09:33:57 EDT 2012
Needs 36000 nodes when I try - but it does get assert.
Will look into it.
John Forrest
On 22/10/12 19:36, Haroldo Santos wrote:
> I confirm this bug - it also exists in the sequential version of CBC.
>
> There is a simple way to reproduce it, using the last CBC revision
> (1792).
>
> Just run in instance glass4 from miplib
> http://miplib.zib.de/miplib2003/miplib2003/glass4.php
>
> After 6000 nodes it crashes:
>
> Cbc0010I After 6000 nodes, 2633 on tree, 1.9500178e+09 best solution,
> best possible 8.0000498e+08 (64.08 seconds)
> Cbc0038I Full problem 392 rows 317 columns, reduced to 311 rows 67
> columns - too large
> cbc: CbcSOS.cpp:303: virtual double CbcSOS::infeasibility(const
> OsiBranchingInformation*, int&) const: Assertion `pi[iRow] >= -1.0e-3'
> failed.
>
>
>
> On Mon, Oct 22, 2012 at 4:14 PM, vladimir voloshinov
> <vladimir.voloshinov at gmail.com <mailto:vladimir.voloshinov at gmail.com>>
> wrote:
>
> Dear ?bc team,
> can you help with the following problem.
> =====================
> Short description:
> A few days ago, I compiled and installed OS package (on Linux
> Ubuntu 12.*)
> (from svn co https://projects.coin-or.org/svn/OS/releases/2.6.0 and
> I replaced COIN-OS/Cbc with Cbc 2.7,7 "manually").
>
> We have a MILP problem which causes multi-threaded running of Cbc
> (with more than 4 threads, release build without debugging symbols) to
> throw "Segmentation fault" after long run period (hundred of thousands
> nodes) in CbcModel::addCuts1(...)
> /* $Id: CbcModel.cpp 1783 2012-06-06 13:33:48Z stefan $ */).
> But on running debug build of the same COIN-OS at the same problem
> caused "Assertion failed" in
> CbcSOS.cpp:303: virtual double CbcSOS::infeasibility() ...
> Assertion `pi[iRow] >= -1.0e-3' failed.
> So, two questions:
> 1. Are there any recommendation to set compilation or running options
> to avoid segmentation fault for multi-threaded Cbc running?
> 2. What about that mysterious problem with assertion in CbcSOS.cpp ?
> (It looks like a check of dual variables sign, but why with double
> const ?!)
> =====================
>
> Detailed description.
> We are working with some job-shop schedule problem formulated as a
> MILP. After some experiments with LP_SOLVE (it works too long) and
> Glpk (much faster) I decided to use COIN Cbc as MILP solver.
> "make" and "make test" finished OK.
>
> It was everything ok until I tried to solve some MILP problem (AMPL
> stub file is uploaded to
> http://dcs.isa.ru/~vladimirv/coin-or/cbc/w6_t30_shuffledDyn.nl
> <http://dcs.isa.ru/%7Evladimirv/coin-or/cbc/w6_t30_shuffledDyn.nl>).
> It become a hard one and I tried to run Cbc with multiple-threads
> (COIN-OS/configure had been run with --enable-cbc-parallel).
> After a number of running
> ./OSSolverService -nl w6_t30_shuffledDyn.nl -osol cbc.osol
> (a number of threads has been set in <solverOption name="threads"
> solver="cbc" value="nnn" /> tag of cbc.osol, uploaded to
> http://dcs.isa.ru/~vladimirv/coin-or/cbc/cbc.osol
> <http://dcs.isa.ru/%7Evladimirv/coin-or/cbc/cbc.osol>)
> I got "Segmentation fault" error for 4, 6, 8 threads,
> (2-threaded sample is still running), it is worth to mention that
> the SIGSEGV
> signal appeared after long run period (after check of hundred
> thousands and
> even million B&B tree nodes).
> When I tried to detect source of error by gdb:
> gdb --args ./OSSolverService -nl w6_t30_shuffledDyn.nl -osol cbc.osol
> I've got (see the end of sysout, after ~40000 nodes ):
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x7ffff5e93700 (LWP 22249)]
> 0x0000000000796a63 in CbcModel::addCuts1(CbcNode*,
> CoinWarmStartBasis*&) ()
> (gdb) bt
> #0 0x0000000000796a63 in CbcModel::addCuts1(CbcNode*,
> CoinWarmStartBasis*&) ()
> #1 0x0000000000796ea2 in CbcModel::addCuts(CbcNode*,
> CoinWarmStartBasis*&, bool) ()
> #2 0x00000000007a46fa in CbcModel::doOneNode(CbcModel*, CbcNode*&,
> CbcNode*&) ()
> #3 0x00000000007c1c1a in doNodesThread(void*) ()
> #4 0x00007ffff79bce9a in start_thread () from
> /lib/x86_64-linux-gnu/libpthread.so.0
> #5 0x00007ffff69bedbd in clone () from
> /lib/x86_64-linux-gnu/libc.so.6
> #6 0x0000000000000000 in ?? ()
>
> To get more info I compiled debug build:
> ./configure --prefix=/home/vladimirv/coin-or/COIN-OS/build.debug
> --disable-shared --enable-cbc-parallel --enable-debug
> "make" and "make test" finished OK.
>
> BUT, after that, the run of single thread debug version permanently
> throws another
> [New Thread 0x7ffff6694700 (LWP 4629)]
> Cbc0010I After 0 nodes, 1 on tree, 17.666667 best solution, best
> possible 5.5506109 (5.32 seconds)
> Cbc0038I Full problem 2664 rows 210 columns, reduced to 2083 rows 93
> columns - too large
> OSSolverService: CbcSOS.cpp:303: virtual double
> CbcSOS::infeasibility(const OsiBranchingInformation*, int&) const:
> Assertion `pi[iRow] >= -1.0e-3' failed.
>
> The further check revealed that "suspicious" pi[iRow] is about
> -0.005. ??!!
>
> Sincerely yours,
> --
> Vladimir V. Voloshinov,
> Ph.D, head of lab. C-3 "Distributed computing algorithms"
> Center of Grid-technologies & Distributed Computing,
> http://dcs.isa.ru,
> web: http://dcs.isa.ru/drupal/ru/staff/vladimirv
>
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>
>
>
>
> --
> =============================================================
> Haroldo Gambini Santos
> Computing Department - Universidade Federal de Ouro Preto - UFOP
> email: haroldo [at ] iceb.ufop.br <http://iceb.ufop.br>
> home/research page: www.decom.ufop.br/haroldo/
> <http://www.decom.ufop.br/haroldo/>
>
> "Computer science is no more about computers than astronomy
> is about telescopes." Edsger Dijkstra
>
>
>
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