[Coin-discuss] problem with initialsolve

[Matthew Saltzman]

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
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>                                                                   Subject
>                                       [Coin-discuss] problem with
>             04/11/06 12:50 PM         initialsolve
>
>
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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