[Clp] How to get integral solution for totally unimodular matrix?

[John J Forrest]

Lasse,

I don't see that the changes I suggested would cause that.  Try just
replacing initialSolve by resolve - also print out size of model before
resolve.  If you want to send me stuff directly do so (as long as it is not
too large).

John Forrest


                                                                                              
  From:       Lasse Kliemann <lasse-list-coin-2009 at mail.plastictree.net>                      
                                                                                              
  To:         clp at list.coin-or.org                                                            
                                                                                              
  Date:       06/24/2009 02:53 PM                                                             
                                                                                              
  Subject:    Re: [Clp] How to get integral solution for totally unimodular matrix?           
                                                                                              





* Message by -John J Forrest- from Wed 2009-06-24:

> If you replace the initialSolve by resolve, then the problem goes away.
> However the long thin strategy is 50 times faster!
>
> To get good performance and normal simplex characteristics you need to
add
> ten lines.  I attach a modified integral.cpp.

Thank you, John, for the explanation and the example code.

I ran it, but it keeps complaining about an empty problem:

   Clp3002W Empty problem - 250 rows, 0 columns and 0 elements

The problem *is* loaded via 'assignProblem'; I also tried:

   si->getModelPtr()->loadProblem(*matrix, col_lb, col_ub,
        objective, row_lb, row_ub);

to no avail.


Thank you for a hint.
Lasse
[attachment "atthbeby.dat" deleted by John J Forrest/Watson/IBM]
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