Xpress-MP Google Group

Re: Batch files using Console Optimizer

2008-05-12T23:31:27Z

Just for clarification. Once I run the shell script, the Optimizer
asks me to enter a problem name. I hit enter to and 'exit' . On
exiting XPRESS, the rest of the script tries to execute in Linux and
since Linux does not know what readprob, minim are, etc, I get an
error.

Thanks again,
J

Batch files using Console Optimizer

2008-05-12T23:26:31Z

Hello,
I am using XPRESS optimizer on Linux. I am not Linux savvy but I want
to run a shell script that runs a bunch of .LP format files. I wrote a
sample shell script to run one file as follows:

optimizer
test
readprob test.lp
minim
global
writeprtsol

When I run the shell script, the Optimizer is asking me for a problem

solution time reduction in case of Mixed- Integer- Programming

2008-05-12T13:49:09Z

Dear all,

does anyone know how to save solution time, and if there is a method
to relax a problem for XPRESS?
Our instructor gave us a project on site construction and
transportation cost minimization that takes quite long time to solve
(15 min). The problem is to reduce this time and a was wondering if we

Re: How to get the number of nodes?

2008-05-09T12:08:12Z

I believe the current node in the stats section will give you the
number of how many nodes are solved so far.

How to save output

2008-05-09T12:06:51Z

Hope somebody can help me with this:

Is there any way to save the stats from running a MIP model? Like the
best solution, solution time, best bound and so forth? Or a printout
of the BB-tree and the MIP search?

And how can I write the output to a file and get it saved?

Thank you in advance

How to get the number of nodes?

2008-05-07T01:34:34Z

Dear

I'm using Xpress-IVE to solve integer programming.
The question is, how to get the number of nodes solved so far in
Xpress-IVE?

thanks.

Re: Garbage Collection in Mosel? How to free memory??

2008-04-30T12:09:46Z

Thanks!!

On 30 Apr., 13:23, "Chris Oakley" <chris.oak...@dashoptimization .com>
wrote:

RE: Garbage Collection in Mosel? How to free memory??

2008-04-30T11:23:06Z

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

Garbage Collection in Mosel? How to free memory??

2008-04-30T11:04:31Z

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

RE: How to delete constraints and variables?!

2008-04-30T11:03:39Z

Re: How to delete constraints and variables?!

2008-04-30T11:00:30Z

Generally spoken: How do I delete already declared variables and free
related memory? How can I provide a garbage collection manually?

RE: Save GAP

2008-04-30T10:52:22Z

There isn't a direct way to retrieve the gap but you can get the value for
best bound and mipobjval and calculate it yourself either at the end or in
the intsol callback at each mip solution.
There is an error in the documentation for miprelstop.
Chris.
______________________________ __
Dash Optimization - part of Fair Isaac

Re: Save GAP

2008-04-30T10:35:49Z

Sorry, I don't no either. But, perhaps a workaroung would be
sufficient: What for do you want to save the GAP? I just need it to
analyze my results afterwards, and therefore I just save the standard
output stream of the console to a file using fselect.

Re: Save GAP

2008-04-29T16:49:46Z

HELLO!

there is no function for saving the gap. i am also interesyting about
that. the only way i found for saving the gap is copying it.

Ln() function in the objective

2008-04-29T11:29:50Z

Hi,

I am doing an entropy optimizing problem where the objective is
defined to be:

-PROB(p,q)*ln(PROB(p,q))

PROB(p,q) are MPVAR

Some are the probabilites are restricted to be zero. How do I set this
objective function to zero when a PROB(p,q) is zero?

Thanks