News - Dash Optimization Presents at the Tenth Annual INFORMS Computing Society Conference

January 3rd-5th, 2007
University of Miami,
Miami, Florida

Dash Optimization will be giving two presentations at the Tenth Annual INFORMS Computing Society Conference. The presentations are:

Title: Solving Hard Mixed Integer Programming Problems

Contributing Authors: Alkis Vazacopoulos, Richard Laundy, Gabriel Tavares

Abstract: Xpress-MP features sophisticated, robust algorithms to quickly and accurately solve industry's most demanding Mixed Integer Programming Problems (MIPs) with millions of variables and constraints.

Practical evidence of the Xpress performance will be shown on MIPLIB-2003. Using Xpress-2006 five MIPs from MIPLIB-2003 (a1c1s1, atlanta-ip, msc98-ip, rd-rplusc-21 and swath) were solved for the first time on a single standard computer. The first known feasible solution of problem stp3d has been found by Xpress. In addition, new local search heuristics built on top of Xpress-2006 found improved solutions for all of the remaining (seven) open problems from MIPLIB 2003. Finally, it is shown how to speed-up Xpress MIP solve times through the use of automatic fine-tuning and the usage of parallel-based algorithms

Title: Branch-and-Price with Xpress-Mosel [Download Presentation]

Contributing Authors: Hernan Wurgaft, Alkis Vazacopoulos

Abstract: We present the use of Mosel's functionality for model management and synchronization of concurrent models to implement Branch-and-Price algorithms. These algorithms, which apply column generation at every node of the branch-and-bound tree, have traditionally been hard to implement because they require specialized branching and specialized relaxation techniques. We show how Mosel eases the implementation of Branch-and-Price through its abilities to interact with the Xpress-Optimizer and to manage the sequential and parallel solving of multiple models. We present a number of examples and we also discuss how to extend these ideas for Branch, Cut, and Price algorithms.

The conference page is located at: http://moya.bus.miami.edu/~ebaker/

If you have any questions about this conference, Dash Optimization, or Xpress-MP please feel free to email: .