A publication of the Advanced Simulation & Computing Division, NA-121.2, NNSA Defense Programs
September 2009
NA-ASC-500-09—Issue 12 Printable Version
(~2MB PDF)
The Meisner Minute
Editorial by Bob Meisner
This past quarter brought with it significant change and progress.
In May, Michael Strayer and I formed the Exascale Initiative Steering Committee (EISC) that recognizes the need for ASC and the Office of Advanced Scientific Computing Research in the Office of Science to collaborate if we are to be successful at achieving exascale computing by the end of next decade. The committee is comprised of representatives from Lawrence Livermore, Los Alamos, Sandia, Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Pacific Northwest national laboratories.
Sandia Wins a 2009 R&D 100 Award for Catamount Light Weight OS for Multi-Core Processors
The latest version of the Catamount Operating System (OS) has been dubbed “Catamount N-Way” because it supports “N” cores per compute node. It exploits existing features of multi-core processors to deliver significant improvements in data access performance for parallel computing applications. Catamount currently runs on the Red Storm Supercomputer located at Sandia, which has 6720 dual-core and 6240 quad-core nodes.
Largest Ever Plasma Particle-in-Cell Calculation Enabled by Roadrunner
In support of the National Ignition Campaign (NIF) and Laboratory Directed Research and Development, the Roadrunner supercomputer (located at Los Alamos National Laboratory [LANL]) has been used during its open-science stabilization phase to perform fully kinetic plasma simulations of laser-plasma interaction (LPI) under conditions encountered in inertial confinement fusion experiments on NIF. f/8 laser speckles were modeled under NIF plasma conditions to understand onset and saturation of Raman backscatter (SRS) instability. See the schematic showing Lawrence Livermore National Laboratory pf3D modeling of laser and Hydra modeling of ignition caption with LANL VPIC simulation volume.
Validation of W80 Abnormal Mechanical Model to Probabilistically Assess Nuclear Safety
In a study funded by the Advanced Simulation and Computing (ASC) Program, a model of the W80 is undergoing verification and validation (V&V) for probabilistic assessment of nuclear safety in abnormal mechanical environments such as handling drop accidents.
Early Science Runs on Dawn Push the Forefront of Predictive Simulation
The 500-teraFLOPS ASC Sequoia Initial Delivery System (Dawn), an IBM machine of the same lineage as BlueGene/L, has immediately proved itself useful as several initial science results—performed from April through August—demonstrated ground-breaking science, enhanced code performance, and some of the highest resolution, largest simulations ever run in their respective scientific field.
VisIt Performance Reaches New Heights
Three weeks after HPCwire lauded Lawrence Livermore National Laboratory’s VisIt visualization software for tackling datasets up to 2 trillion zones, VisIt ran on the Dawn supercomputer and eclipsed 4 trillion zones.
Isocontour of 4 trillion zones
resampled from a supernova
calculation.
New Uncertainty Quantification Method Models Random Fields in Weapon Applications
A new uncertainty quantification (UQ) capability has been developed to model random surface contact and friction in mechanical joints. This capability is needed to model accurately the behavior of weapon components and subsystems when subject to structural vibration environments such as those that occur in a warhead during atmospheric re-entry.
Los Alamos’ Roadrunner Permitting VPIC Simulations of Unprecedented Scale
Magnetic reconnection is a basic plasma process involving the explosive conversion of magnetic field energy into particle kinetic energy, including high-speed flows, thermal heating, and highly energetic particles. This process is thought to play an important role in a wide variety of applications ranging from solar flares, to the Earth’s magnetosphere, to magnetic fusion devices. Three-dimensional simulations of magnetic reconnection are computationally challenging due to the large separation of spatial and temporal scales inherent to most applications. This is particularly true for kinetic simulations where both ion and electron kinetic scales must be fully resolved.
Material Response Variability Characterized and Propagated in Nonlinear Structural Response Simulations
In a Verification & Validation-funded project, we characterized and reproduced variability, observed in material characterization testing, by using a SIERRA Mechanics material model. Optimization was used to derive a baseline fit to the average of a collection of tension test data for 6061-T6 aluminum. Sensitivity studies and statistical software were used to determine input factors driving the response metrics.
Los Alamos Advances Predictive Capability in Nuclear Forensics
Los Alamos National Laboratory has demonstrated leadership capabilities in simulation code capability in nuclear forensics as a result of advances in areas such as nuclear cross sections, neutron transport packages, hydrodynamics, and setup and optimization tools. For example, advances in ASC simulation tools have enabled LANL designers to perform outstandingly well in various blind-exercises over the past year or two. Generally these exercises consist of synthetic data provided to the labs, which then have 2-4 weeks to assess the design. Complete details can’t be given here, except to say that LANL’s assessments have been recognized for their accuracy.
Los Alamos Pioneers Modeling Emission from Supernovae
Supernovae play an important role across a wide range of fields in physics and astronomy. They mark the endpoint in the life of stars but are an important source of energy to galaxies and play a role in the formation of new stars. They are produced in the formation of stellar-massed compact objects and, possibly, the seeds of the most massive black holes in the universe. They produce the bulk of the heavy elements in the universe and are the foundations of nuclear astrophysics.
NNSA and DOE Supercomputers Continue to Dominate TOP500 List; Dawn Makes First Appearance
NNSA and DOE continue to dominate the TOP500 list of the world's most powerful supercomputers with 5 of the top 10 high-performance computing systems on the list released Tuesday at the International Supercomputing Conference (ISC 09) in Hamburg, Germany.
Hyperion Project Web Site Now Live
The Hyperion Project Web site is now available. Hyperion teams LLNL with 10 computing industry leaders to accelerate the development of powerful next-generation Linux clusters.
ASC Salutes Code Physicist Rob Rieben
At the tender age of 21, Rob Rieben visited Lawrence Livermore National Laboratory as an undergraduate physics student through the Summer Institute in Applied Science program. The large-scale science performed at LLNL fascinated the budding physicist, and he decided then he would pursue his scientific career at the famous weapons lab.
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