[Cbc] cbc on LP not transferring status

[John J Forrest]

Matt,

It was a "feature".  As the problem had no integer variables, it never got
anywhere near Cbc itself.  So the solution in CbcModel was never set up -
and that is tested for optimality.

Have added a few lines to CbcSolver.cpp in trunk.

John


                                                                                                   
  From:       Matthew Galati <Matthew.Galati at sas.com>                                              
                                                                                                   
  To:         "cbc at list.coin-or.org" <cbc at list.coin-or.org>                                        
                                                                                                   
  Cc:         "dip at list.coin-or.org" <dip at list.coin-or.org>                                        
                                                                                                   
  Date:       10/28/2009 10:12 PM                                                                  
                                                                                                   
  Subject:    [Cbc] cbc on LP not transferring status                                              
                                                                                                   
  Sent by:    cbc-bounces at list.coin-or.org                                                         
                                                                                                   





The following code and example shows an issue that is showing up in DIP.

https://projects.coin-or.org/Dip/browser/trunk/Dip/bugs/main.cpp
https://projects.coin-or.org/Dip/browser/trunk/Dip/bugs/PRICE_AND_CUT_subProb_relax0.n0.c0.p0.b0.lp


It happens when CBC is used to solve an LP. It seems to solve it fine but
when checking the status, it returns 0 for isProvenOptimal.



[magala at orclus71
bugs]$ ./a.out ../../build-g/Dip/examples/MILPBlock/PRICE_AND_CUT_subProb_relax0.n0.c0.p0.b0.lp

Coin Cbc and Clp Solver version 2.3.2, build Oct 27 2009
command line - cbc -log 3 -solve -quit (default strategy 1)
logLevel was changed from 1 to 3
Presolve 0 (-2) rows, 0 (-3) columns and 0 (-2) elements
Empty problem - 0 rows, 0 columns and 0 elements
Optimal - objective value 1.85108
After Postsolve, objective 1.85108, infeasibilities - dual 0 (0), primal 0
(0)
Optimal objective 1.851079952 - 0 iterations time 0.002, Presolve 0.00
Total time 0.00
cbc.isProveOptimal() = 0


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