Xpress-MP Google Group

Stochastic Programming Module

2009-06-07T17:07:41Z

Hi all,

I have been using the "mmsp" module for solving a multistage recourse
model. I have been searching on the website to find the underlying
algorithm(s) that are used by this module. Can anyone help?
I believe that the recourse model is reset as a large scale LP
equivalent en solved accordingly. Is this correct?

E-1013 Infeasible constraint

2009-05-26T17:39:55Z

I'm getting the error E-1013 Infeasible constraint in my model with
code on line 78: "sum(l in T)M(i,l,1)*l+sum(j in E,l in T)P(i,j,l,1)
*l>=Es(i)" How can I solve this?

This is the code for my model=

model Carpool
uses "mmxprs"; !gain access to the Xpress-Optimizer solver

!optional parameters section

XPRS_TOP and XPRS_LIN

2009-05-24T17:08:28Z

Hello

What is the difference between XPRS_TOP and XPRS_LIN?

Thanks

XpressMP on Leopard

2009-05-22T14:07:37Z

Dear Madam, Sir

may I ask you whether there is any chance to see XpressMP running on
Mac Os X in the next months?

I do not refer explicitly about the porting of Xpress-Ive (which
however make the development really easy), what is
really important to me is the possibility to use XpressMP on mac os x

Converting a string to numeric?

2009-05-11T18:32:33Z

Hi guys

I need some help. I have a file with both numeric and character data.
and i imported these to a 2d array(of type string) in mosel.

Now, this is what I wanna try...

Can I access a column from this array and then extract the numeric
value (in effect i wanna convert the string type info to numeric data

Re: PLZZZZZZZZZ HELP

2009-05-11T17:23:06Z

I am not sure if I did understand the question... but if what you want
is to load an array from a dat file you can do it by means of for
loops as:

forall(a in 1..A,b in 1..B) do
read(D(a,b))
end-do

You do not need to strictly start from 1.

Interpretation of the Solution

2009-04-15T16:59:59Z

Hi,

I have used Xpress in my dissertation and must interpret my results
properly. In the book as well as in the net I could find nothing the
fitting, for this reason the last attempt is to write here.

Please, explain me how to interpret the Rows (constrains), Columns
(variable), Non-zero elements as well as Simplex iterationens.

xPress Mosel IVE!

2009-04-14T13:00:24Z

Hello!

I'm a greenhorn in programming and modelling and I hope somebody could
help me!

I have the following problem with xPress Mosel IVE:

I have a linear program with the following side condition: (Transport
condition)

y1l >= LB1 or y1l = 0

l ... stands for distribution center or consumer

Optimization Libraries Student Version

2009-04-02T20:43:51Z

Hi there,

I was wondering if it is possible to obtain the Xpress Optimization
library for UNIX operating systems as a student version? I just need
the optimizer (and a mex interface), no fancy IDE.

Thanks,

Max

Xpress MP student edition can do sensitivity analysis?

2009-03-31T15:36:50Z

Good afternoon
I have a doubt about the student version of xpress MP. I want to know
if the student version of xpress MP can do sensitivity analysis?
Best regards
André Soares

sensitivty analysis on the student edtion

2009-03-30T17:14:00Z

Good afternoon

I have a doubt about the student version of xpress MP. I want to know
if the student version of xpress MP can do sensitivity analysis?

Best regards
André Soares

Information about ucbdata

2009-03-17T11:05:07Z

Dear all,
We are trying to lead the branching variable in the B&B performed by
XPRESS.
To this end, we have found the callback function XPRS_CB_CHGBRANCH
that in
principle allows to choose the new branching var. by means of the
ucbdata
procedure.

Our question is about the parameter of this function. In principle,

LP gone horribly wrong

2009-03-08T17:41:03Z

Hi there!
I'm trying to solve the following problem: I've got five production
plants and numerous customers and I have to decide what amount of a
product should be produced by which plant to serve the needs of the
customers.

As I'm new to the XPress MP (Student version) I implemented that in

How to know when the B&B has found an Integer solution

2009-03-03T10:26:50Z

I am working in a Branch and Cut algorithm.

I have to apply a procedure to add cuts when but only when the node is
an integer solution. Somebody knows how to determine if one node is
and Integer solution?

Kind regards

Stacked column

2009-02-06T14:58:29Z

Is there anybody that can help me graphing stacked columns (thats what
they call it in MS excel) in Xpress (IVE)? It is a power modelling
problem where I want total power production in each period as columns,
and the different power generators as different colors in the columns.
For example if power production in period 1 is 20MWh coal and 30MWh