OSiL: An Instance Language for Optimization

Distributed computing technologies such as Web Services are growing rapidly in importance in today’s computing environment. In the area of mathematical optimization, it is becoming increasingly common to separate modeling languages from optimization solvers. In fact, the modeling language software, solver software, and data used to generate a model instance might reside on different machines … Read more

LPFML: A W3C XML Schema for Linear and Integer Programming

There are numerous algebraic modeling languages for generating linear programs and numerous solvers for computing solutions to linear programs. This proliferation of modeling languages and solvers is frustrating to modelers who find that only certain languages connect to certain solvers. One way to encourage modeler-solver compatibility is to use a standard representation of a problem … Read more

Numerical Issues and Influences in the Design of Algebraic Modeling Languages for Optimization

This paper draws from our experience in developing the AMPL modeling language, to show where numerical issues have been crucial to modeling language design and where modeling language advances have strongly influenced the design of solvers. Citation Proceedings of the 20th Biennial Conference on Numerical Analysis, Dundee, Scotland, D.F. Griffiths and G.A. Watson, eds., University … Read more

A Server for Automated Performance Analysis of Benchmarking Data

As part of Performance World, we describe an automation server (PAVER: http://www.gamsworld.org/performance/paver) to help facilitate reproducible performance analysis of benchmarking data for optimization software. Although PAVER does not solve optimization problems, it automates the task of performance data analysis and visualization, taking into account various performance metrics. These include not only robustness and efficiency, but … Read more

Extending an Algebraic Modeling Language to Support Constraint Programming

We describe extensions to algebraic modeling languages and their solver interfaces that will be needed to take advantage of constraint programming solvers, particularly in the area of combinatorial optimization. Citation Technical Report, Department of Industrial Engineering and Management Sciences, Northwestern University (2001); based on a shorter version that appeared in the Proceedings of the Third … Read more

Symbolic-Algebraic Computations in a Modeling Language for Mathematical Programming

AMPL is a language and environment for expressing and manipulating mathematical programming problems, i.e., minimizing or maximizing an algebraic objective function subject to algebraic constraints. AMPL permits separating a model, i.e., a symbolic representation of a class of problems, from the data required to specify a particular problem instance. Once AMPL has a problem instance, … Read more