Computers for Lattice Field Theories

Parallel computers dedicated to lattice field theories are reviewed with emphasis on the three recent projects, the Teraflops project in the US, the CP-PACS project in Japan and the 0.5-Teraflops project in the US. Some new commercial parallel computers are also discussed. Recent development of semiconductor technologies is briefly surveyed in relation to possible approaches toward Teraflops computers.Comment: 15 pages with 16 PS figures, review presented at Lattice 93, LaTeX (espcrc2.sty required

Dynamic adaptive parallel architecture integrates advanced technologies for petaflops-scale computing

Teraflops-scale computing systems are becoming available to an increasingly broad range of users as the performance of the constituent processing elements increases and their relative cost (e.g. per Mflops) decreases. To the original DOE ASCI Red machine has been added the ASCI Blue systems and additional 1 Teraflops commercial systems at key national centers. Clusters of low cost PCs employing COTS network technologies (e.g. Beowulf-class systems) will make peak Teraflops performance available for less than 2M in the near future for certain classes of well behaved problems. Future larger systems include the Japanese Earth Simulator with a peak performance of 40 Teraflops and three larger ASCI systems anticipated to provide peak performance of 10, 30, and 100 Teraflops culminating in 2005. These systems use existing or near term conventional technologies and architectures with some specialized integration logic and networking. While the peak performance goals can be satisfied through this strategy over the next decade, two major challenges confront the high performance computing community: (1) how to aggressively accelerate performance to the operational regime beyond a Petaflops, and (2) how to achieve high efficiency for a wide range of applications. The Hybrid Technology Multithreaded (HTMT) computer is under development by an interdisciplinary team of investigators to address both problems through an innovative combination of advanced technologies and dynamic adaptive architecture. This paper describes the strategy embodied by the HTMT architecture and discusses the key factors that may enable it to achieve two to three orders of magnitude performance with respect to today's largest systems at a cost and power consumption of only a factor of two to three times those same present day systems

The status of US Teraflops-scale projects

The current status of United States projects pursuing Teraflops-scale computing resources for lattice field theory is discussed. Two projects are in existence at this time: the Multidisciplinary Teraflops Project, incorporating the physicists of the QCD Teraflops Collaboration, and a smaller project, centered at Columbia, involving the design and construction of a 0.8 Teraflops computer primarily for QCD.Comment: Contribution to Lattice 94. 7 pages. Latex source followed by compressed, uuenocded postscript file of the complete paper. Individual figures available from [email protected]

Architectural choices for the Columbia 0.8 Teraflops machine

We discuss the hardware design choices made in our 16K-node 0.8 Teraflops supercomputer project, a machine architecture optimized for full QCD calculations. The efficiency of the conjugate gradient algorithm in terms of balance of floating-point operations, memory handling and utilization, and communication overhead is addressed. We also discuss the technological innovations and software tools that facilitate hardware design and what opportunities these give to the academic community.Comment: Contribution to Lattice 94. 3 pages. Latex source followed by compressed, uuenocded postscript file of the complete pape

Multidisciplinary computational aerosciences

As the challenges of single disciplinary computational physics are met, such as computational fluid dynamics, computational structural mechanics, computational propulsion, computational aeroacoustics, computational electromagnetics, etc., scientists have begun investigating the combination of these single disciplines into what is being called multidisciplinary computational aerosciences (MCAS). The combination of several disciplines not only offers simulation realism but also formidable computational challenges. The solution of such problems will require computers orders of magnitude larger than those currently available. Such computer power can only be supplied by massively parallel machines because of the current speed-of-light limitation of conventional serial systems. Even with such machines, MCAS problems will require hundreds of hours for their solution. To efficiently utilize such a machine, research is required in three areas that include parallel architectures, systems software, and applications software. The main emphasis of this paper is the applications software element. Examples that demonstrate application software for multidisciplinary problems currently being solved at NASA Ames Research Center are presented. Pacing items for MCAS are discussed such as solution methodology, physical modeling, computer power, and multidisciplinary validation experiments