[Coin-lpsolver] Re: getBInvRow() question, Coin-lpsolver Digest, Vol 34, Issue 2

[Gleb Belov]

Dear John,

now I disable scaling, call primal(0,7) and then getBInvRow() works 
fine, at least on the small example I tested. I think I can live with that.

In the long term, however, it would be helpful to coorect this. Or, at 
least, add a comment in the embedded docu.

Thank you
Gleb

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>    1. Re: getBInvRow() question (John J Forrest)
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> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 5 Sep 2007 12:10:34 -0400
> From: John J Forrest <jjforre at us.ibm.com>
> Subject: Re: [Coin-lpsolver] getBInvRow() question
> Cc: coin-lpsolver at list.coin-or.org
> Message-ID:
> 	<OF3D45BD2F.1A707EE8-ON8525734D.0056D025-8525734D.0058F5A0 at us.ibm.com>
> Content-Type: text/plain; charset="us-ascii"
>
> 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> 
> Sent by: coin-lpsolver-bounces at list.coin-or.org
> 09/05/2007 10:57 AM
>
> To
> coin-lpsolver at list.coin-or.org
> cc
>
> 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