Creating and Maintaining Effective Large-Scale Scientific Computing Applications

Balancing Ease-of-Use, Extensibility, and Performance Requirements

Richard Barrett, co-author of Templates for the Solution of Linear Systems: Building Blocks for Iterative Methods and contributing programmer for the ASCI Stockpile Stewardship Program

2—4 pm Tuesday, January 13, 2004, 109 Butrovich

On October 2, 1992, President Bush signed into law the FY1993 Energy and Water Authorization Bill that established a moratorium on U.S. nuclear testing. President Clinton extended the moratorium on July 3, 1993. These decisions ushered in a new era by which the U.S. ensures confidence in the safety, performance, and reliability of its nuclear stockpile. The Advanced Simulation and Computing Program (ASCI) is an integral and vital element of our nation’s Stockpile Stewardship Program. ASCI provides the integrating simulation and modeling capabilities and technologies needed to combine new and old experimental data, past nuclear test data, and past design and engineering experience into a powerful tool for future design assessment and certification of nuclear weapons and their components.

These computational physics simulations consist of hundreds of thousands of lines of code, written using multiple programming languages. These codes must execute accurately, consistently, and efficiently on a variety of computing platforms throughout their multiple decade lifetimes. They must withstand the participation of many code developers, each of whom brings different skill sets to the project. They must adapt to dynamic user requirements, and thus be amenable to the inclusion of new algorithms and other improvements.

Barrett’s focus is on abstracting the necessary complexities of the distributed memory parallel processing environment in a way that is natural to the code developer, yet enables the incorporation of sophisticated computer science ideas “under-the-hood.” Barrett will illustrate how these requirements have been managed by describing a variety of specific applications and computational kernels. These applications include hydrodynamic algorithms operating on unstructured and semi-structured dynamic meshes, various radiation transport approaches (Sn and Monte Carlo), and an approach to solving linear systems when the system properties are poorly understood.

About Richard Barrett

Barrett has been a technical staff member at Los Alamos National Laboratory for the past ten years, contributing to a variety of physics simulation code development projects, mainly within the ASCI program. Prior to going to Los Alamos he was a charter member of the Innovative Computing Laboratory at the University of Tennessee.

CONTACT: Jenn Wagaman, ARSC Public Affairs Coordinator, (907) 450-8662,

Arctic Region Supercomputing Center PO Box 756020, Fairbanks, AK 99775 | voice: 907-450-8600 | email:

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