[Coin-osi-devel] Turning presolve off with OsiXpr

[Matthew Saltzman]

On Mon, 12 Jun 2006, Francois Margot wrote:

>
> How do I get Xpress to turn off preprocessing? I use:
>
>    si->setHintParam(OsiDoPresolveInInitial, false, OsiForceDo);
>
> where si is a pointer to an OsiXprSolverInterface object.
> But this has no effect, apparently. I can not find a
> setHintParam() method in OsiXprSolverInterface. Is this missing
> or does the code in OsiSolverInterface::setHintParam be enough?

Most SIs (XPRESS included) don't respect hints.  The most straightforward 
thing is to hook the problem object and call the appropriate XPRESS 
function directly.  Unfortunately, it looks like the current XPRESS 
implementation doesn't support that directly.

You want something akin to The OsiCpx getEnvironmentPtr().  I'd implement 
it, but I no longer have an XPRESS license.  If you would like to, it 
would be appreciated.

 		Matt

>
> Francois

-- 
 		Matthew Saltzman

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