[Coin-lpsolver] Parametric Analysis using CLP + OSI

[John J Forrest]

Paulo,

It depends how you are picking up basis information.  With a problem of  n 
columns and m rows Clp numbers the structural variables (column) 0 through 
n-1 and the artificial/slack variables n through n+m-1.

John Forrest



"Paulo J. S. Silva" <pjssilva at ime.usp.br> 
Sent by: coin-lpsolver-bounces at list.coin-or.org
03/08/2005 09:24 AM

To
John J Forrest/Watson/IBM at IBMUS
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coin-lpsolver at list.coin-or.org, coin-lpsolver-bounces at list.coin-or.org
Subject
Re: [Coin-lpsolver] Parametric Analysis using CLP + OSI






Hi John,

The new version is working for me too. Thanks.

I have now another question for the list. I am solving a problem in
Standard form:

min c'x
s.t Ax = b
    x >= 0

I ask Clp to solve it and it gives me the right answer. However, if I
ask the basis, there are "invalid" indices in the basis (the problem has
460 varibles and the optimal basis have indices like 469). What is
happening here. Are those indices from artificial variables added to
find a initial basic solution?

Best,

Paulo

Obs: If you want I have the mps file for such problem.

-- 
Paulo José da Silva e Silva 
Professor Assistente do Dep. de Ciência da Computação
(Assistant Professor of the Computer Science Dept.)
Universidade de São Paulo - Brazil

e-mail: pjssilva at ime.usp.br        Web: http://www.ime.usp.br/~pjssilva

Teoria é o que não entendemos o    (Theory is something we don't)
suficiente para chamar de prática. (understand well enough to call) 
                                   (practice)



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