[Coin-discuss] problem with initialsolve

[John J Forrest]

Matt,

We accept BV and UI.  Not sure we can accept SC as no OsiSolverInterface 
definition.  I would like to be able to accept S1 and S2 sets if we decide 
to extend to SC.

May get round to putting in LI if noone else does first.

John



Matthew Saltzman <mjs at ces.clemson.edu> 
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04/19/2006 08:47 AM
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Re: [Coin-discuss] problem with initialsolve






On Wed, 19 Apr 2006, John J Forrest wrote:

> Anureet,
>
> Cplex seems to accept a non standard MPS format bound.  There are LI 
bounds
> which I have never heard of (they obviously allow a lower bound of minus
> infinity).  The Mps standard is MI and when I changed them to that then 
the
> problem was feasible.
>
> CoinMpsIo should have given error messages on unrecognized bound types - 
I
> think I have corrected that.

These are part of CPLEX's and other solvers' integer extensions--an 
alternative to the MARKER format.

LI is CPLEX-speak for a variable that must be integer and has the 
specified lower bound.  UI is integer with specified upper found, BV is 
binary, SC is semi-continuous with given upper bound (presumably the lower 

bound must be specified with an LB).

I think we probably want to accept these extensions. There are other CPLEX 

extensions that may be more or less common that we may want to consider 
supporting in the future.


                                 Matt

>
> John Forrest
>
>
>
>             Anureet Saxena
>             <anureet at yahoo.co
>             m> To
>             Sent by:                  coin-discuss at list.coin-or.org,
>             coin-discuss-boun         anureet at cmu.edu
>             ces at list.coin-or. cc
>             org
> Subject
>                                       [Coin-discuss] problem with
>             04/11/06 12:50 PM         initialsolve
>
>
>             Please respond to
>             Discussions about
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>
>
>
> hi,
>
> I am trying to solve a linear program by
> OsiClpSolverInterface::initialSolve() which is known to be feasible and
> bounded (cplex solves it to optimality). However, OsiClp reports the 
linear
> program to be primal infeasible. The .mps file for the linear program 
and a
> short code for verification can be found at,
>
> http://www.andrew.cmu.edu/user/anureets/COIN_tmp/workspace_my.tgz .
>
> It would be very helpful if someone could suggest what is going wrong 
and a
> possible way to fix it.
>
> regards,
> Anureet Saxena
>
>
>
>
>
>
>
> Anureet Saxena
> anureet at cmu.edu
> anureet at yahoo.com
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-- 
                                 Matthew Saltzman

Clemson University Math Sciences
mjs AT clemson DOT edu
http://www.math.clemson.edu/~mjs
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