[Cbc] Error on "fiber" miplib2003 instance with CBC 2.3 stable

[John J Forrest]

Jean-paul,

I am unable to reproduce on my 32 bit Linux.  When did it start to fail?
The only change I have put in recently is in a bit of code that fiber would
not visit.

John Forrest


                                                                                          
  From:       "Watson, Jean-paul" <jwatson at sandia.gov>                                    
                                                                                          
  To:         "cbc at list.coin-or.org" <cbc at list.coin-or.org>                               
                                                                                          
  Date:       10/07/2009 04:44 PM                                                         
                                                                                          
  Subject:    [Cbc] Error on "fiber" miplib2003 instance with CBC 2.3 stable              
                                                                                          
  Sent by:    cbc-bounces at list.coin-or.org                                                
                                                                                          





Hi,

I am obtaining the following error via CBC 2.3 stable (built as of this AM
following an svn update) on the miplib2003 “fiber.mps” instance (on a
vanilla redhat 64-bit linux system):

Coin:import fiber.mps
At line 1 NAME           fiber
At line 2 ROWS
At line 367 COLUMNS
At line 2491 RHS
At line 2522 BOUNDS
At line 3777 ENDATA
Problem fiber has 363 rows, 1298 columns and 2944 elements
Coin:solve
Continuous objective value is 156083 - 0.00 seconds
Cgl0002I 3 variables fixed
Cgl0003I 0 fixed, 0 tightened bounds, 4 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 3 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 2 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 1 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 1 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 1 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 1 strengthened rows, 0 substitutions
Cgl0004I processed model has 290 rows, 1055 columns (1055 integer) and 2465
elements
Cbc0006I The LP relaxation is infeasible or too expensive
Cuts at root node changed objective from 1.79769e+308 to -1.79769e+308
Probing was tried 0 times and created 0 cuts of which 0 were active after
adding rounds of cuts (0.000 seconds)
Gomory was tried 0 times and created 0 cuts of which 0 were active after
adding rounds of cuts (0.000 seconds)
Knapsack was tried 0 times and created 0 cuts of which 0 were active after
adding rounds of cuts (0.000 seconds)
Clique was tried 0 times and created 0 cuts of which 0 were active after
adding rounds of cuts (0.000 seconds)
MixedIntegerRounding2 was tried 0 times and created 0 cuts of which 0 were
active after adding rounds of cuts (0.000 seconds)
FlowCover was tried 0 times and created 0 cuts of which 0 were active after
adding rounds of cuts (0.000 seconds)
TwoMirCuts was tried 0 times and created 0 cuts of which 0 were active
after adding rounds of cuts (0.000 seconds)
Result - Finished objective 3983 after 0 nodes and 0 iterations - took 0.05
seconds (total time 4.83)

The LP relaxation is definitely feasible, and it doesn’t look all that
expense based on statistics.

Any ideas?

Thanks,

Jean-Paul

--

Dr. Jean-Paul Watson
Discrete Math and Complex Systems Department
Sandia National Laboratories
P.O. Box 5800, MS 1318
Albuquerque, NM 87185-1318
(505) 845-8887
jwatson at sandia.gov




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