[Cbc] CBC Stable 2.3 stuck on tiny MIP

[John J Forrest]

Unable to reproduce - runs fine for me.


                                                                                                                     
  From:       Matthew Galati <Matthew.Galati at sas.com>                                                                
                                                                                                                     
  To:         "cbc at list.coin-or.org" <cbc at list.coin-or.org>                                                          
                                                                                                                     
  Date:       10/03/2009 03:33 PM                                                                                    
                                                                                                                     
  Subject:    [Cbc] CBC Stable 2.3 stuck on tiny MIP                                                                 
                                                                                                                     
  Sent by:    cbc-bounces at list.coin-or.org                                                                           
                                                                                                                     





I let it run for a while but no progress was reported - it looks stuck.

http://coral.ie.lehigh.edu/~magh/tmp/PRICE_AND_CUT_subProb_relax.n21.c0.p5.b0.lp

[magala at orclus71 bin]$ ./cbc PRICE_AND_CUT_subProb_relax.n21.c0.p5.b0.lp
Coin Cbc and Clp Solver version 2.3stable, build Oct  3 2009
command line - ./cbc PRICE_AND_CUT_subProb_relax.n21.c0.p5.b0.lp (default
strategy 1)
Continuous objective value is -9372.08 - 0.00 seconds
Cgl0003I 0 fixed, 0 tightened bounds, 2 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 2 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 2 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 2 strengthened rows, 0 substitutions
Cgl0004I processed model has 6 rows, 20 columns (20 integer) and 30
elements
Cbc0038I Solution found of -9120.53
Cbc0038I Branch and bound needed to clear up 1 general integers
Cbc0038I Full problem 6 rows 20 columns, reduced to 2 rows 5 columns
Cbc0038I Cleaned solution of -8884.54
Cbc0038I Before mini branch and bound, 19 integers at bound fixed and 0
continuous
Cbc0038I Mini branch and bound improved solution from -8884.54 to -8884.54
(0.01 seconds)
Cbc0038I Round again with cutoff of -8908.14
Cbc0038I Reduced cost fixing fixed 4 variables on major pass 2
Cbc0038I Solution found of -9120.53
Cbc0038I Branch and bound needed to clear up 1 general integers
Cbc0038I Full problem 7 rows 20 columns, reduced to 3 rows 5 columns
Terminated

Cplex 10.2 gives:
  MIP - Integer optimal solution:  Objective = -8.9305853659e+03
  Solution time =    0.02 sec.  Iterations = 33  Nodes = 34
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