[Osi] Problems with OsiXprSolverInterface and XPress 18.1

[Matthew Saltzman]

Yes, the XPRESS OSI badly needs some love.

Please file a ticket for this.  If you are able to attempt a patch, that
would be a help, too.  http://projects.coin-or.org/Osi/newticket.

Thanks.


On Fri, 2008-04-25 at 14:39 +0200, Christian Plum wrote:
> Hi All
>  
> Im working on a COIN based project, where I have implemented a model
> in FLOPC++ and until now solved the model using CBC through the
> OsiCbcSolverInterface, which has worked great.
>  
> I would like to pump up the speed of the computation, so Im trying to
> solve the problem instances using the Xpress solver.
>  
> Unfortunately I am getting the following error: 
>  
>         Xpress-Optimizer v18.10.00
>         Hyper capacity, MIP (10 threads), Barrier (10 threads),
>         Network, QP/MIQP
>         (c) Copyright Dash Associates 1984-2007
>          
>         incrementInstanceCounter:: numInstances 0
>         incrementInstanceCounter:: numInstances 1
>         FlopCpp: Number of constraint blocks: 3
>         FlopCpp: Number of individual constraints: 34
>         FlopCpp: Number of variable blocks: 2
>         FlopCpp: Number of individual variables: 48
>         FlopCpp: Number of non-zeroes (including rhs): 106
>         FlopCpp: Generation time: 7.922
>         ERROR: XPRSglobal in line 92 error 32 occured
>         Solution of first instance (x)
>         0 0 ERROR: XPRSgetmipsol in line 823 error 32 occured
>           -6.27744e+066
>         0 1   -6.27744e+066
>         0 2   -6.27744e+066
>         0 3   -6.27744e+066
>         1 0   -6.27744e+066
>         1 1   -6.27744e+066
>         1 2   -6.27744e+066
>         1 3   -6.27744e+066
>         2 0   -6.27744e+066
>         2 1   -6.27744e+066
>         2 2   -6.27744e+066
>         2 3   -6.27744e+066
>         ...
>  
> The documentation of Xpress refers error 32 as: 
>  
>         Subroutine not completed successfully, possibly due to invalid
>         argument.
>  
> Which hasn't helped me much.. Im suspcting that OsiXprSolverInterface
> is for an older version of XPress ? And that the problem format could
> have changed ? 
>  
> I am cabable of solving simpler non-COIN based problems using Xpress.
>  
> Looking forward to your help!
>  
> /Christian
>  
>  
> 
>  
>  
> 
>  
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-- 
                Matthew Saltzman

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