[Coin-lpsolver] getBInvRow() question

Sun Sep 9 13:56:54 EDT 2007

code to deal with scaling and binvrow now in clp/trunk

             John J                                                        
             Forrest/Watson/IB                                             
             M at IBMUS                                                    To 
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                                       Re: [Coin-lpsolver] getBInvRow()    
                                       question                            
             05.09.2007 12:10                                              

Gleb,

You can see an example of using OsiClpSolverInterface and scaling (for
getBInvARow/Col) and just looking at nonzeroes of result at about line 1378
of Osi/test/OsiClpSolverInterfaceTest.cpp.

However you wish to use getBInvRow not getBInvARow and want to use it from
Clp itself.  I gather you have got it to work with scaling switched off?
Looking at code in ClpSimplex.cpp it looks as if that is older code than in
OsiClpSolverInterface and does not deal with scaling unlike ARow and ACol.

If you want I can update code in ClpSimplex.cpp to handle scaling - do you
want me to?  May not be before Monday - send me a note if I don't post
anything by Tuesday.

John Forrest

 Gleb Belov <gleb.belov at tu-dresden.de>                                     

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 09/05/2007 10:57 AM                                                       
                                                                   Subject 
                                                    [Coin-lpsolver]        
                                                    getBInvRow() question  

Hi,

I am new to CLP. I want to use it without OSI to save compilation time.
My problem concerns getBInvRow(). It returns just rows of the identity
matrix.
I solved my model by calling ClpSimplex::primal(0,7).

I looked at OsiClpSolverInterface::enableSimplexInterface(bool). As I
understand, it disables scaling. Is it necessary for getBInvRow() to work?

Sincerely,
Gleb

--
Mit freundlichen Gruessen

G. Belov
----------------------------------------------------------------------
Dr. Gleb Belov                                Gleb.Belov at tu-dresden.de
Wiss. Assistent                   http://www.math.tu-dresden.de/~belov
Technische Universitaet Dresden                 Tel: +49 351 463 34186
Institut fuer Numerische Mathematik             Fax: +49 351 463 34268
Mommsenstr. 13                            Tel. priv.:+49 351 3743754
01062 Dresden

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