XpressMP

The Xpress-MP modelling and optimization system Xpress-IVE accepts as input an Xpress-Mosel model file. This file includes the algebraic description of the problem, an optimization call (or calls), and any customised report writing statements required. Xpress-IVE calls the Xpress-Optimizer to solve problems as required, and can solve linear, integer, quadratic or mixed integer quadratic programming problems (LP, MIP, QP, MIQP).

The Xpress-Mosel language includes the features of a standard programming language, such as loops (forall, while, repeat/until), conditions (if/then/else, case) and procedures/functions, allowing you to perform complex operations, and even algorithms or heuristics that make repeated calls to the Optimizer. The Mosel model may also include statements to set Optimizer control parameters to non-default values.

Mosel may also be used in the manner of a standard modeling language, to export the problem described to an MPS format matrix file. This file can be input manually into the Xpress-Optimizer or a number of other linear or integer programming solvers. For some brief background on algorithms and software for linear and integer programming, the reader is directed to the Optimization Tree area on the NEOS Guide.

The new version of Xpress-IVE lets you create and edit Mosel models, solve them on NEOS and get results back into Xpress-IVE seamlessly. A free, fully featured student version of Xpress-IVE is available here

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Phone: +1 (201) 567 9445
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info@dashoptimization.com

The email address you provide or use for submissions to Xpress-MP solvers may be forwarded to Dash Optimization for promotional purposes.

Information on using Xpress-IVE may be found in the Xpress-IVE help system. Examples may be found at the Dash Optimization web site, www.dashoptimization.com, under Products | Examples | Mosel models.

Using the NEOS Server with Xpress-Mosel

To solve a linear or integer programming problem using the Xpress-Mosel modeling language as input, you need only submit the Mosel model file, containing the algebraic description of the problem, optimization call(s), and any customised report writing statements required. NEOS will compile and run the Mosel model, calling the Xpress-Optimizer as required. The Mosel model may also include statements to set Optimizer control parameters to non-default values. Examples of models and commands in Mosel format can be found via links on the Sample Submissions page.

The model is specified by a model file, and optionally, a data file. If a data file is submitted, it should be accessed from the model file through initializations from 'model.dat'. The data file you submit is always renamed model.dat, so you cannot access it through the original name you gave it.

The model file can contain most of the commands Mosel has to offer, with the following exceptions. System libraries 'mmsystem' and 'mmect' cannot be called on in order to protect the integrity of our systems. Data can also not be written to arbitrary files with the initialize to 'filename' command. Data written to standard output will be returned along with your job results.

This NEOS solver executes on a Sun workstation. Sun, Sun Microsystems, the Sun Logo and the Powered by Sun Logo are trademarks or registered trademarks of Sun Microsystems, Inc. in the U.S. and other countries.

The model file can contain most of the commands Mosel has to offer, with the following exceptions. System libraries 'mmsystem' and 'mmect' cannot be called on in order to protect the integrity of our systems. Data can also not be written to arbitrary files with the initialize to 'filename' command. Data written to standard output will be returned along with your job results.
Mosel File:

If a data file is submitted, it should be accessed from the model file through initializations from 'model.dat'. The data file you submit is always renamed model.dat, so you cannot access it through the original name you gave it.
Data File:

Select whether you want to solve the problem using the SIMPLEX or BARRIER algorithm
Algorithm:

An email address is required for any submissions to XPRESS solvers. This email address will be forwarded to Dash Associates and may be used by Dash Optimization for promotional purposes.
Email Address:

>Enter any additional comments here (e.g. to identify the data for your own information.) These comments will be returned with your results.
Comments:

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Please do not click the 'Submit to NEOS' button more than once.

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