DOE SciDAC Review Office of Science
 
ISSN: 1935-0570


Cover Story
Interview with Dr. Thom Mason, p7

Front Cover A realistic model of the N3 sensitized anatase(101)/acetonitrile interface, which is key in dye sensitized solar cells, p21

Back Cover Discrete ordinates transport calculation of the power distribution in a full-core pressurized water reactor benchmark problem at OLCF. Visualization by VisIt on the OLCF LENS visualization cluster. Courtesy of T. Evans, ORNL.

CONTENTS
NUMBER 17 SPRING 2010
4
7
INTERVIEW: DR. THOM MASON COVER STORY
Leading the Push Toward Exascale
Dr. Thom Mason has served as Laboratory Directory at Oak Ridge National Laboratory since July, 2007.
10
SCALABLE MOLECULAR SIMULATION
Toward an Understanding of Complex Chemical Systems
Energy production and security are among the major challenges facing the nation. To extend performance levels beyond what is now possible for the production, storage, and use of energy, technological breakthroughs must occur.
22
UNIFIED PARALLEL C
The Evolving Ecosystem for Parallel Software
Academic and commercial communities have long sought a language that could hide the complexity of parallel machines while providing high performance across machine scales. This would lower the barrier to entry for parallel computing, make parallel machines more attractive as commercial products, and create a strong workforce for high-end scientific programming.
30
PROGRAMMING MODELS
More Scalability, Less Pain
This is the story of a simple programming model, its implementation for extreme computing, and a breakthrough in nuclear physics. A critical issue for the future of high-performance computing is the programming model to use on next-generation architectures.
38
SWIFT
Scalable Parallel Scripting for Scientific Computing
Researchers have been extending the time-tested programming technique of scripting into new realms of performance. Through the Swift parallel scripting language, they aim to enhance scientific productivity by enabling scripts to execute many copies of ordinary application programs at very high degrees of parallelism.
54
MAGELLAN 
Exploring Cloud Computing for DOE’s Scientific Mission
Cloud computing is gaining traction in the commercial world, with companies offering pay-to-play cycles to help organizations meet cyclical demands for extra computing power. But can such an approach also meet the computing and data storage demands of the nation’s scientific community?
60
EDITORIAL: DR. DOUGLAS B. KOTHE
Nuclear Energy: Back to the Future
Dr. Doug Kothe, Director of Science in the Oak Ridge Leadership Computing Facility, discusses the roles ASCR and high-performance computing can play in the future of nuclear energy in the United States.
64
BACK COVER
Discrete ordinates transport calculation of the power distribution in a fullcore pressurized water reactor benchmark problem, which required the solution of 78 billion unknowns with the “Denovo” neutron transport application on the Jaguar XT5 leadership system at OLCF. Visualization was enabled by VisIt on the OLCF LENS visualization cluster to perform the 3D volume rendering of the power distribution in the core model. Courtesy of T. Evans, ORNL.