A publication of the Office of Advanced Simulation & Computing, NA-114, NNSA Defense Programs
December 2007
NA-ASC-500-07—Issue 5
Printable Version(~2MB PDF)
The View from HQ
It is time for New Year’s Resolutions or perhaps New Year’s resolve. I know that, in general resolutions are easy to make and easy to let slide. My intent is to resolutely move forward on an initiative in which I believe very strongly.
Nuclear Forensics Traces Nuclear Explosions
If someone detonated a nuclear device, would we be able to identify where the material came from? Nuclear Forensics is “post-event” analysis of a nuclear event, and it would help to discover the source of a nuclear device. The ASC integrated codes already have significant capability to simulate nuclear events with a certain degree of confidence, but those are mostly our devices and our underground nuclear tests, under controlled conditions. What happens if, say, a terrorist group steals a device from a foreign country and sets it off in an underground parking garage? What can the ASC codes do to help with understanding the event?
Innovative Computing Technique Earns Livermore Team the Gordon Bell Prize
A team of scientists from the Lawrence Livermore National Laboratory Physical Sciences Directorate and IBM won the prestigious Gordon Bell Prize in Peak Performance with a breakthrough physics calculation run on the recently expanded BlueGene/L system. The award was announced at the Supercomputing 2007 conference (SC07) in Reno, Nevada. Computation Associate Director Dona Crawford said, “These scientific computing awards underscore the vital role the ASC Program plays in NNSA’s Stockpile Stewardship Program as well as in national security in a global context.”
Sandia and Livermore Collaborate on Radiation-MHD Code Development
Dimitri Kusnezov (NNSA), Joan Woodard (SNL), and Bruce Goodwin (LLNL), recently signed a Memorandum of Agreement “to establish an explicit collaboration between Sandia National Laboratories (SNL) and Lawrence Livermore National Laboratory (LLNL) for the purposes of developing, verifying, and validating a radiation-MHD simulation capability for high density physics (HEDP) and above ground experiments (AGEX) within the KULL framework. A goal for this collaboration is to leverage the complementary strengths of the LLNL and SNL projects (radiation-hydrodynamics and magneto-hydrodynamics (MHD), respectively) to create ‘best in class’ capabilities in a cost-effective fashion.”
Micron-Scale Atomistic Studies of Shock Ejecta Production Using BlueGene/L
Los Alamos researchers recently completed a series of simulations of shock ejecta production in copper. This fragmentation and atomization process is difficult to study experimentally, and various theories have been proposed. Atomistic-level simulations will contribute to the development of physics-based models as part of the LANL “Science@Scale” effort (see September 2007 ASC eNews article). In particular, the dependence of ejecta production and transport on shock pressure (e.g., below and above the shock melting transition, to study material strength effects) and background gas (with either a vacuum as in previous simulations or an inert gas atmosphere) have been studied.
First Demonstration of Predictive Capability for Weapon Systems in Hostile Nuclear Environments
A Sandia team has completed the first demonstration of a high-fidelity predictive capability for combined system-generated electromagnetic pulse (SGEMP) effects. Without underground testing, a robust SGEMP predictive capability such as that demonstrated by Sandia is needed to design and qualify new systems (e.g., RRW1).
ASC Software Quality Engineering Group Gives Defects Some Static
The ASC Verification and Validation (V&V) software quality engineering (SQE) group at Lawrence Livermore National Laboratory used a new static analysis tool, the automated static analyzer (ASA), to analyze over 2 million lines of ASC source codes and to verify that more than 3,000 defects were repaired in much less time than would be possible using standard debugging techniques. This work was performed in support of an FY07 level 2 ASC milestone.
Accident Response of SafeGuards Transporters Simulated
For the first time, Sandia National Laboratories analysts simulated the accident response of a full-scale SafeGuards Transporter (SGT), including the weapons cargo. Testing of full-scale SGT accident scenarios is very limited and, as a result, provides little insight into the effects of different impact conditions and does not have the ability to assess the efficacy of design modifications of the transporter. As a result, computational simulation is the only way to address the diverse scenarios that must be explored.
Pit Lifetime Assessment Team Awarded Defense Programs Award of Excellence
On Wednesday, December 5, 2007, Mr. William Ostendorff, NNSA’s Principal Deputy Administrator, presented an Award of Excellence to the Los Alamos National Laboratory (LANL) Pit Lifetime Assessment Team. The 120-member team was responsible for meeting LANL’s 2006 Level 1 Milestone for lifetime assessments, which involved substantial ASC resources, including BlueGene/L. The team delivered a science-based assessment of plutonium-aging effects on pit lifetimes and primary performance for the deployed LANL stockpile systems. Their studies included a reanalysis of the underground nuclear test records and an extensive experimental and computational investigation of the mechanical, physical, and chemical property changes caused by plutonium aging.
High-Fidelity B61 Weapon-in-a-Fire Sensitivity Analysis Study Completed
A sensitivity analysis study using massively parallel calculations of a B61 subject to various weapon-in-a-fire scenarios was recently completed on the Thunderbird computer at Sandia National Laboratories. These studies employed Sandia’s DART tools to construct the computational model of the B61, along with Sandia’s Sierra thermal/mechanical simulation software to model the fire environment.
Common Tri-Lab Capacity Computing Moves Closer to Goal
The NNSA initiative to establish common computational environments on tri-lab computing systems will take major steps forward in FY08. For several years, a tri-lab effort known as Tripod has been under way to promote cost-effective, portable environments on the Linux-based cluster systems at Livermore, Los Alamos, and Sandia national laboratories.
Expanded BlueGene/L Retains Rank as World’s Fastest Supercomputer
BlueGene/L retained its number one ranking on the new Top500 list of the world’s fastest supercomputers at the international Supercomputing 2007 conference in Reno, Nevada. BlueGene/L clocked 478.2 teraFLOPS on LINPACK, the industry standard measure of high-performance computing. Recently expanded to accommodate the growing demand for high-performance systems able to run the most complex nuclear weapons science calculations, BlueGene/L now has a peak speed of 596 teraFLOPS.
Roadrunner Videotape Segments on the Web
A Los Alamos National Laboratory communications team created a video about the Roadrunner Project for an exhibit at SC07. Divided into five segments on the Web site, the video features top-level managers, computer scientists, and plasma physicists discussing the challenges and what we have to look forward to in the future of high-performance computing. The segments are 1) Petascale: the Next Generation of Computing; 2) Hybrid Computing Architecture; 3) Programming for the Future; 4) Science@Scale; and 5) the Science and Technology Challenges. Go to http://www.lanl.gov/orgs/hpc/roadrunner/video.shtml
Speed of Light Is Too Slow
The following press release highlights a computer code called VPIC that takes advantage of optimized microprocessors such as the Roadrunner base system. The release was published by the American Physics Society during the annual meeting of the Division of Plasma Physics the week of November 12, 2007.
“Ultrafast Programs Developed for Future Ultrafast Computers,” by Kevin N. Roark
Left: Magnetic islands and drift-kink instability observed in 3D large-scale fully kinetic VPIC simulations run on Roadrunner base system of magnetic reconnection in electron-positron plasma.
Livermore Computer Scientists Receive R&D100 Award for hypre
Lawrence Livermore National Laboratory computer scientists have developed a software library called hypre that allows researchers to use supercomputers such as BlueGene/L and ASC Purple more effectively to conduct larger, more detailed simulations faster than before. This cutting-edge technology garnered a 2007 R&D100 award from the trade journal R&D Magazine for developing advances with commercial potential among the top 100 industrial inventions worldwide for 2006.
Algorithms Decrease Solution Time Ten-Fold
Sandia National Laboratories’ ASC Algorithms Milestone team, led by Roscoe Bartlett, developed and demonstrated a full vertical integration of numerical algorithms in the Trilinos Library with the Charon semiconductor device modeling code. Compared to prior approaches, these new algorithms have demonstrated up to a ten-fold reduction in time-to-solution while providing more accurate and robust results.
SC07 Cluster Challenge Committee Proclaims: Perceived Entry Barrier to Supercomputing Has Dropped Significantly
At Supercomputing 2007 (SC07), six teams of undergraduates, supported by their chosen vendor partners, competed in a test of performance on the conference floor. Teams were given a few simple rules (26 amps and no one on the team can have a degree) and the summer to design the system that would perform best on a workload consisting of Linpack benchmarks (the industry standard High Performance Computing [HPC] Challenge) and three open source applications: GAMESS, a molecular chemistry application from AmesLab; POP, an ocean circulation model from Los Alamos; and POVRay, a popular ray tracing application.
Representing ASC at Supercomputing 2007, from the Ground Up
Tri-lab specialists in hardware, networking, electrical, computer support, graphic design, videography, communication, and administration at Livermore, Los Alamos, and Sandia national laboratories combined resources and talents to design, build, and staff the NNSA ASC tri-lab booth at Supercomputing 2007 (SC07). The display by the three laboratories, Y-12, and the five alliances showcased technical breakthroughs achieved on behalf of the nation’s Stockpile Stewardship Program (SSP).
High-Performance Computer Support Team Reinvents Itself
“Better, Faster, Cheaper” is the three-pronged goal of Los Alamos National Laboratory’s High-Performance Computer Support Team (HPCST) for in-house computer hardware support. The HPCST has reinvented itself by redefining its long-established mission of monitoring all LANL’s supercomputers, clusters, and facilities. In addition to monitoring these systems, the team has taken on the responsibility of providing maintenance and support for all the supercomputer systems currently installed at the laboratory. The HPCST staffs the operations center in the Metropolis Center for Modeling & Simulation 24 hours a day, 7 days a week. It was this availability of personnel, in part, that sparked the innovative initiative to provide in-house computer maintenance and support services.
Weapons Radiochemistry
The radiochemistry team at Los Alamos has compiled the ingoing isotopic ratios of materials for four events of interest to LANL’s Applied Physics (X) Division designers for the first quarter of FY08. Radiochemistry will process these data through a code developed by Chemistry Division, producing radiochemical parameters needed by X Division to run their codes.
ASC Salutes
“The reward for me,” said Brian S. Pudliner, code physicist at Lawrence Livermore National Laboratory, “is to sit in the audience at a high-level technical briefing and hear about an issue of national interest being solved with a tool I helped create.”
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