Xpress-MP Google Group

How customize the branch and bound algorithm?

vinti.cin...@gmail.com (Cinzia) — Thu, 06 Jun 2008 09:12:09 UT

Sorry,
i need to introduce a heuristic procedure for each node of the branch
and bound tree. The problem is that in my procedure i need to make an
optimization with minimize(XPRS_LIN,""), but it's impossible if the
optimizer already running. How can i do? I read about EMOSL, but i
didn't find it.

errors running models

h...@maths.soton.ac.uk (Honora Smith) — Wed, 06 Jun 2008 12:41:16 UT

I'm using Model 2.2.0, mmxprs version 1.6.2, mmive version 1.18.5
I'm finding that programs that used to run under previous versions now
don't. I've changed arrays to :, when initialised from file. Some of
the arrays are initialised successfully, but there is an "error runing
model or execution interrupted" and no other indication of what is

.NET wrapper throws an BadImageFormatException

david.ondra...@gmx.de (morgoth) — Mon, 06 Jun 2008 18:32:17 UT

Hi,

I tried to use the xprsdn.dll library in a visual studio 2005 project,
but every time i try to call a function (i.e. Init(string) or Init())
in the optimization namespace, I get a System.BadImageFormatException .
What am I doing wrong?
My System is a Vista x64 Business, could this be a problem?

Want a PAN card??

er.ritesh.agra...@gmail.com (ritesh agrawal) — Thu, 05 May 2008 05:00:30 UT

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Help with using xprs.dll

lfcmen...@gmail.com (spartan) — Tue, 05 May 2008 15:01:00 UT

I am writting a program that needs to call the methods from xprs.dll
file; i.e. XPRSlicense, ....
This program is written in C#, how can I accomplish this?

getsol(x:mpvar) -> returns wrong value!

tstra...@gmail.com (cees) — Sun, 05 May 2008 14:32:12 UT

Hi!

I rerun an optimization model several times. To check the results I
calculate the objective value "manually", by summing up all terms of
the objective function. For example: One part of the objective
consists of the sum of setup costs:

sum(i in 1..I, j in 1..J, t in HR) ( X0(i,j,t) * SC(i,j) )

Java, but using a library Xpress

ljon...@gmail.com (Jonata) — Fri, 05 May 2008 23:41:17 UT

Good night 4 all,
I got the Xpress-Student and I´d want to designe a java program that
invokes a library Xpress. How can I do it? I didn't find neither
the .jar file in web nor instructions of how to use it.
Thanks,

Jonata

Batch files using Console Optimizer

dinakar.g...@gmail.com (Jordan) — Mon, 05 May 2008 23:26:31 UT

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

xenia....@gmail.com (laguerriere) — Mon, 05 May 2008 13:49:09 UT

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

How to save output

anne.cathrine.blaks...@gmail.com (AC) — Fri, 05 May 2008 12:06:51 UT

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?

namsu....@gmail.com (namsu.ahn@gmail.com) — Wed, 05 May 2008 01:34:34 UT

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.

Garbage Collection in Mosel? How to free memory??

tstra...@gmail.com (cees) — Wed, 04 Apr 2008 11:04:31 UT

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

Ln() function in the objective

blink...@gmail.com (Blinks) — Tue, 04 Apr 2008 11:29:50 UT

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

Re: How to delete constraints and variables?!

tstra...@gmail.com (cees) — Wed, 04 Apr 2008 11:00:30 UT

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

Updating constraints in a minimizing problem

nopo...@gmail.com (Luiz Menezes) — Wed, 04 Apr 2008 16:33:40 UT

!!!!! CONSTRAINT !!!!!

forall(i in insI,j in insJ,l in insI,m in insJ |
exists(isgreater_aux(i,j,l,m)) and isgreater_aux(i,j,l,m)=true)
sum(k in insK)k*x(i,j,k) >= sum(k in insK)k*x(l,m,k) +1

!!!!! after I call a cicle !!!!!

forall(i in insI) do
forall(j in insJ) do
forall(l in insI) do