[Coin-discuss] Setting solver parameters in OSI

[Jesper Hansen]

Thanks. I managed to get it working by setting the values directly. I'm
looking a bit at the XPRESS solver interface as well. Many of the same
parameters exist and could easiliy be included in OSI.

Now, I have a slightly different problem with XPRESS. I'm using the version
Xpress-MP 2003B also refered to as Xpress-Optimizer 14.05. The OSI XPRESS
interface is depreciated and different things described in their manual is
getting a bit difficult to do with the old interface. So the question is, if
anyone is planning to update the interface?

In the new XPRESS API you use a handle to the problem of the type XPRSprob,
which I believe was not necessary in the old API. Now, can anyone tell me
how (if possible) to get this handle when using OSI?

Jesper

> -----Original Message-----
> From: coin-discuss-admin at www-124.ibm.com
> [mailto:coin-discuss-admin at www-124.ibm.com]On Behalf Of Brady Hunsaker
> Sent: Thursday, September 11, 2003 6:06 PM
> To: coin-discuss at oss.software.ibm.com
> Subject: Re: [Coin-discuss] Setting solver parameters in OSI
>
>
> On Thu, 2003-09-11 at 10:30, Jesper Hansen wrote:
> > Hi
> >
> > I'm solving an IP problem with use of OSI. Is there any easy way to set
> > solver parameters in OSI?
> >
> <snip>
>
> For the additional CPLEX parameters, you need to do it directly using
> the solver environment, as you suggested.  I don't use CPLEX regularly,
> but looking at the OsiCpx code, it looks like the method
>   CPXENVptr OsiCpxSolverInterface::getEnvironmentPtr();
> is what you want to get the environment pointer.  It looks like this is
> a public method, so you should be able to use it directly.  Then you can
> call the CPLEX parameter routines yourself.  Somebody more familiar with
> OsiCpx please correct me if that's wrong.
>
> If you also need the LP pointer, use
>   CPXLPptr OsiCpxSolverInterface::getLpPtr();
>
> Part of the difficulty with having a common interface is the variety of
> solver options and parameters.  As you noticed, OSI handles certain
> parameters that are common to all solvers.  We do need to come up with a
> long term solution to this problem, which will probably include more
> options handled by the OSI.  Of course, even then there will be cases
> when you'll need to fall back on this method for some solver-specific
> options.
>
> Let us know if you run into difficulties with this approach,
>
> Brady
>
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