> -----Original Message-----
> From: xpressmp@googlegroups.com [mailto:xpressmp@googlegroups.com] On
> Behalf Of cees
> Sent: 30 April 2008 12:05
> To: Xpress-MP
> Subject: Garbage Collection in Mosel? How to free memory??

> How can I undo the declaration of variables, respectively, constraints,
> if they becom superfluous? I don't want to override them, I want to
> delete them and free related memory! Anyone an idea?

> Thanks a lot!!!

> -------------------

> This thread replaces the undermentioned:

> "Hi! My optimization model is extended stepwise, that is, it is set-up
> and solved for a specific planning horizon and extended afterwards to
> cover more periods. This is done to simulate a rolling horizon
> environment. Therefore, in each simultion run the optimization model is
> extended with new constraints and variables. Only in under special
> circumstance some already inialized constraints in variable are
> superfluous. I would like to delete these not needed constraints and
> variables, because for large simulation instances the model exceeds the
> available RAM of my computer and Xpress terminates. There are a lot of
> not needed constraints, because preprocessing always reduces the
> problem size strongly.

> How do I delete constraints and variables? Does a corresponding
> function to "create" exist? Or could I use "sethidden"? I could image
> that the latter doesn't help to reduce memory usage...

>  Thanks a lot!"

> The basic rule is: a variable is automatically deleted when it is no longer
> referenced (e.g. local variable of a subroutine or deleted from a dynamic
> array using
> 'delcell') _and_ does not appear in any constraint (note that bounds and
> is_* are constraints). Similarly, a constraint is deleted if it is no longer
> referenced and is empty (to clear a constraint give it the value 0:
> myctr:=0).

> ________________________________
> Dash Optimization - part of Fair Isaac
> tel: +44 1926 315862www.dashoptimization.com
> optimization everywhere

> > -----Original Message-----
> > From: xpressmp@googlegroups.com [mailto:xpressmp@googlegroups.com] On
> > Behalf Of cees
> > Sent: 30 April 2008 12:05
> > To: Xpress-MP
> > Subject: Garbage Collection in Mosel? How to free memory??

> > How can I undo the declaration of variables, respectively, constraints,
> > if they becom superfluous? I don't want to override them, I want to
> > delete them and free related memory! Anyone an idea?

> > Thanks a lot!!!

> > -------------------

> > This thread replaces the undermentioned:

> > "Hi! My optimization model is extended stepwise, that is, it is set-up
> > and solved for a specific planning horizon and extended afterwards to
> > cover more periods. This is done to simulate a rolling horizon
> > environment. Therefore, in each simultion run the optimization model is
> > extended with new constraints and variables. Only in under special
> > circumstance some already inialized constraints in variable are
> > superfluous. I would like to delete these not needed constraints and
> > variables, because for large simulation instances the model exceeds the
> > available RAM of my computer and Xpress terminates. There are a lot of
> > not needed constraints, because preprocessing always reduces the
> > problem size strongly.

> > How do I delete constraints and variables? Does a corresponding
> > function to "create" exist? Or could I use "sethidden"? I could image
> > that the latter doesn't help to reduce memory usage...

> >  Thanks a lot!"