M. Torelli

Lbe Simulations Of Rayleigh-Bénard Convection On The Ape100 Parallel Processor

In this paper we describe an implementation of the Lattice Boltzmann Equation method for fluid-dynamics simulations on the APE100 parallel computer. We have performed a simulation of a two-dimensional Rayleigh-Benard convection cell. We have tested the theory proposed by Shraiman and Siggia for the scaling of the Nusselt number vs. Rayleigh number.

A HARDWARE IMPLEMENTATION OF THE APE100 ARCHITECTURE

APE100 processors are based on a simple Single Instruction Multiple Data architecture optimized for the simulation of Lattice Field Theories or other complex physical systems. This paper describes the hardware implementation of the first APE100 machine.

The Software Of The Ape100 Processor

We describe the software environment available for the APE100 parallel processor. We discuss the parallel programming language that we have defined for APE100 and its optimizing compiler. We then describe the operating system that allows to control APE100 from a host computer.

A hodoscope made of resistive plate chambers to identify muons in a fixed targed beauty hadroproduction experiment

Abstract We have built a large area hodoscope to identify muons from semileptonic decays of beauty particles produced in the WA92 experiment at the CERN Super-Proton-Synchrotron. The hodoscope is made of resistive electrode chambers read out with strips of 3 cm pitch. The hodoscope has a fast response with a time resolution of 5 ns and a space resolution of 1 cm. A fast trigger processor selects straight tracks pointing to the interaction vertex in a fixed processing time of 90 ns.

A lattice study of the exclusive B->K*gamma decay amplitude, using the Clover action at beta=6.0

Abstract We present the results of a numerical calculation of the B → K ∗ γ form factors. The results have been obtained by studying the relevant correlation functions at β = 6.0, on an 18 3 × 64 lattice, using the O ( a )-improved fermion action, in the quenched approximation. From the study of the matrix element 〈K ∗ | s σ μν b|B〉 we have obtained the form factor T 1 (0) which controls the exclusive decay rate. The results are compared with the recent results from CLEO. We also discuss the compatibility between the scaling laws predicted by the Heavy Quark Effective Theory (HQET) and pole dominance, by studying the mass- and q 2 -dependence of the form factors. From our analysis, it appears that the form factors follow a mass behaviour compatible with the predictions of the HQET and that the q 2 -dependence of T 2 is weaker than would be predicted by pole dominance.

From APE to APE-100: from 1 to 100 GFLOPS in lattice gauge theory simulations

Abstract We briefly describe the APE processor, a parallel computer currently used in lattice gauge simulations. We also present in greater details the architecture and the implementation of APE-100, a fine grained SIMD processors for lattice gauge theory simulations, similar in structure to APE and designed to provide floating-point performance in the 100 Gflops range.

The teraflop supercomputer APEmille: architecture, software and project status report*

Abstract APEmille is a SPMD parallel processor under development at INFN, Italy, in cooperation with DESY, Germany. APEmille is suited for grand challenges computational problems such as QCD simulations, climate modelling, neural networks, computational chemistry, numerical wind tunnels, seismic and combustion simulations. Its 1 Teraflop/s peak performance and its architecture, together with its language features, allow such applications to execute effectively. APEmille is based on an array of custom arithmetic processors arranged on a tridimensional torus. The processor is optimized for complex computations and has a peak performance of 528 Mflop at 66 MHz. Each processing element has 8 Mbytes of locally addressable RAM. On the software side particular emphasis is devoted to the programming languages that will be available (TAO and C++) and their object oriented, dynamic characteristics: with TAO it is possible to develop language extensions similar to the usual HEP notation; with C++ the portability from and towards different platforms is made possible.

Status of APEmille

Abstract This paper presents the status of the APEmille project, which is essentially completed, as far as machine development and construction is concerned. Several large installations of APEmille are in use for physics production runs leading to many new results presented at this conference. This paper briefly summarizes the APEmille architecture, reviews the status of the installations and presents some performance figures for physics codes.

Progress and status of APEmille

Abstract We report on the progress and status of the APEmille project: a SIMD parallel computer with a peak performance in the TeraFlops range which is now in an advanced development phase. We discuss the hardware and software architecture, and present some performance estimates for Lattice Gauge Theory (LGT) applications.

An overview of the APEmille parallel computer

We describe the architecture of the APEmille Parallel Computer, the new generation of the APE family of processors optimized for Lattice Gauge Theory simulations. We emphasize the features of the new machine potentially useful for applications in other areas of computational physics.