[Cgl-tickets] [COIN-OR Cut Generator Library] #40: CglZeroHalf test fails on i386

[COIN-OR Cut Generator Library]

#40: CglZeroHalf test fails on i386
---------------------+----------------------
 Reporter:  mlubin   |      Owner:  somebody
     Type:  defect   |     Status:  new
 Priority:  blocker  |  Milestone:
Component:  Cgl      |    Version:  trunk
 Keywords:           |
---------------------+----------------------
 Cgl-0.58-2 fails to run `make test` on linux 32-bit x86 systems:

 {{{
 *****************************************
 Testing CglZeroHalf with OsiClpSolverInterface

 Coin0008I LSEU read with 0 errors
 Coin0506I Presolve 28 (0) rows, 88 (-1) columns and 308 (-1) elements
 Clp0006I 0  Obj 0 Primal inf 16.856713 (10)
 Clp0006I 32  Obj 834.68235
 Clp0000I Optimal - objective value 834.68235
 Coin0511I After Postsolve, objective 834.68235, infeasibilities - dual 0
 (0), primal 0 (0)
 Clp0032I Optimal objective 834.6823529 - 32 iterations time 0.002,
 Presolve -0.00
 Clp0006I 0  Obj 834.68235 Primal inf 0.013463473 (2)
 Clp0006I 2  Obj 834.68235
 Clp0000I Optimal - objective value 834.68235
 Zero cuts 2
 lt-unitTest: CglZeroHalfTest.cpp:89: void CglZeroHalfUnitTest(const
 OsiSolverInterface *, const std::string): Assertion `lpRelaxBefore <
 lpRelaxAfter' failed.
 }}}

 {{{
 $ uname -a
 Linux debian 3.10-3-686-pae #1 SMP Debian 3.10.11-1 (2013-09-10) i686
 GNU/Linux
 $ g++ --version
 g++ (Debian 4.8.2-1) 4.8.2
 }}}

 I did some preliminary digging, and it seems like Clp returns a different
 optimal solution to the LP, leading to different cuts being generated
 which fail to improve the objective. It's hard to tell whether this means
 that there is anything wrong with the cut generator or if the test was
 just assuming a particular solution to the LP. Interestingly, when built
 with `--enable-debug`, Clp returns the same solution as on 64-bit machines
 and the test passes. This doesn't necessarily mean that there's a bug
 anywhere though; it could just be floating-point noise.

 This error is blocking updating the Cgl package in Debian.

--
Ticket URL: <https://projects.coin-or.org/Cgl/ticket/40>
COIN-OR Cut Generator Library <http://projects.coin-or.org/Cgl>
A library of mixed-integer programming cutting plane generators.