S&TR | November 2004: From Seeing to Understanding

S&TR | November 2004: From Seeing to UnderstandingEXTRAORDINARILY complex, three-dimensional (3D) supercomputer simulations play a major role in making sure the nation’s nuclear stockpile remains safe and reliable. The simulations require supercomputers performing trillions of operations per second (teraops) often for weeks at a time.
Understanding these simulations depends, to a great extent, on the human eye to carefully scrutinize the vast amounts of simulation information translated into still and moving images. These images allow researchers to gain insight into how a nuclear weapon operates and the effects of aging on its many components. Livermore computer scientists are developing new ways to see and understand the latest simulations by combining inexpensive and ubiquitous microprocessors, graphics cards favored by video-game fans, and open-source software. These components are the heart of the powerful visualization engines that turn reams of data into practical 3D images and movies.
Livermore’s supercomputers dedicated to stockpile stewardship are part of the Advanced Simulation and Computing (ASC) Program. An element of the National Nuclear Security Administration (NNSA), ASC is advancing supercomputing so scientists can make the much higher fidelity physics and engineering simulations needed to assess the safety, reliability, and performance of the nation’s nuclear weapons stockpile.
The 12.3-teraops White machine, in operation since 2000, is Livermore’s most powerful ASC supercomputer. Two new ASC computers, Purple and BlueGene/L, will be delivered in 2005 and housed in Livermore’s new $91-million Terascale Simulation Facility (TSF). Purple will fulfill the ASC Program’s long-sought goal of developing a machine that operates at 100 teraops, considered the entry point for prototype high-fidelity, full weapons system simulations. BlueGene/L, a research and evaluation machine, will have a peak performance of 180 to 360 teraops.
Modern ASC supercomputers, such as White, Purple, and BlueGene/L, consist of thousands of nodes, each composed of 2 to 16 microprocessors. These machines perform what is known as massively parallel computing in which nodes work together on a problem. They are also scalable; that is, simulations can be done with a few nodes or the entire set, and nodes can be added to tackle more difficult problems. (See S&TR, June 2004, Strategic Supercomputing Comes of Age.)
The latest generation of ASC machines generate enormous amounts of data that are sometimes the result of weeks of round-the-clock number crunching. Three-dimensional, time-varying data sets of tens of terabytes (trillions of bytes) are now common, and petabyte (about 1,000 terabytes) data sets are on the horizon. As a result, an urgent need exists to develop new ways to visualize vast quantities of numbers.
- posted by Gp @ 9:02 AM