Cellular processing tools for high-performance simulation

Cellular automata offer a powerful modeling approach for complex systems in which global behavior arises from the collective effect of many locally interacting, simple components. Several tools based on CA are providing meaningful results for real-world applications. Cellular automata represent an efficient paradigm for the computer solution of important problems in science and engineering. Moreover, the CA model lets researchers effectively use parallel computers to achieve scalable performance. As researchers use parallel computers to solve scientific problems, they will need problem representations (paradigms) for this class of computers. Abstract mathematical models that offer an implicitly parallel representation of problems better match those architectures, but could benefit from new high-level languages, environments, and techniques. The three should support all the development steps of computational science applications while hiding architectural details from users. Computational science is also an interdisciplinary field in which many areas converge, and developing applications in this field requires the cooperation of people from different domains. Modeling and simulation using parallel cellular methods helps researchers cooperate by offering both a way to code an algorithm and an integrated environment for developing software     

Test-Based Diagnosis of Faults in Data Exchange Addressing in Computer Systems Using Parallel Model

Test-based diagnosis of an arbitrary real-time computer system represented by a set of functionally related software modules executed on a single computer or concurrently on a set of computers is considered. The approach called diagnosis using a parallel model is used. An efficient procedure for test generation is proposed.     

The concurrent element level processing for nonlinear dynamic analysis on a massively parallel computer

The goal of this paper is to explore parallel methodologies with the desired flexibility, generality and accuracy for nonlinear dynamic finite element analysis on massively parallel computer. This paper tests the generality of the concurrent element processing approach and proposes a basic software design strategy to fully take advantage of features available in massively parallel computers having a hierarchical ring architecture. As a testbed, a large scale general purpose code, DYNA3D as used and modified as appropriate to test proposed parallel design concepts on a KSRI parallel computer.     

Simulating artificial neural networks on parallel architectures

Parallelization is necessary to cope with the high computational and communication demands of neuroapplications, but general purpose parallel machines soon reach performance limitations. The article explores two approaches: parallel simulation on general purpose computers, and simulation/emulation on neurohardware. Different parallelization methods are discussed, and the most popular techniques are explained. While the software approach looks for an optimal programming model for neural processing, the hardware approach tries to imitate the neuroparadigm using the best of silicon technology     

Programming methodology and performance issues for advanced computer architectures

This paper will describe some recent attempts to construct transportable numerical software for high-performance computers. Restructuring algorithms in terms of simple linear algebra modules is reviewed. This technique has proved very succesful in obtaining a high level of transportability without severe loss of performance on a wide variety of both vector and parallel computers. The use of modules to encapsulate parallelism and reduce the ratio of data movement to floating-point operations has been demonstrably effective for regular problems such as those found in dense linear algebra. In other situations it may be necessary to express explicitly parallel algorithms. We also present a programming methodology that is useful for constructing new parallel algorithms which require sophisticated synchronization at a large grain level. We describe the SCHEDULE package which provides an environment for developing and analyzing explicitly parallel programs in FORTRAN which are portable. This package now includes a preprocessor to achieve complete portability of user level code and also a graphics post processor for performance analysis and debugging. We discuss details of porting both the SCHEDULE package and user code. Examples from linear algebra, and partial differential equations are used to illustrate the utility of this approach.     

MM90: A scalable parallel implementation of the Penn State/NCAR Mesoscale Model (MM5)

This paper describes MM90, a parallel regional weather model based on the Penn State/NCAR MM5. Parallelization of finite differencing, horizontal interpolation, and nesting on distributed-memory (message passing) computers is handled transparently using the RSL library package. Fortran90 modules, derived data types, dynamic memory allocation, pointers, and recursion are used, making the code modular, flexible, extensible, and run-time configurable. The model can dynamically sense and correct load imbalances. The paper provides performance, scaling, and load-balancing data collected on the IBM SP2 computers at Argonne National Laboratory and NASA Ames Laboratory. Future work will address the impact of parallel modifications on existing modeling software; an approach using commercially available source translation software is described.     

Massively parallel quantum computer simulator

We describe portable software to simulate universal quantum computers on massive parallel computers. We illustrate the use of the simulation software by running various quantum algorithms on different computer architectures, such as a IBM BlueGene/L, a IBM Regatta p690+, a Hitachi SR11000/J1, a Cray X1E, a SGI Altix 3700 and clusters of PCs running Windows XP. We study the performance of the software by simulating quantum computers containing up to 36 qubits, using up to 4096 processors and up to 1 TB of memory. Our results demonstrate that the simulator exhibits nearly ideal scaling as a function of the number of processors and suggest that the simulation software described in this paper may also serve as benchmark for testing high-end parallel computers.     

Applicative parallelism on a shared-memory multiprocessor

An applicative language, SISAL (streams and iteration in a single-assignment language), is used to examine how effective the applicative approach can be in programming parallel computers. SISAL is a research language for investigating issues in parallel processing, especially for numerical computing. A prototype implementation of SISAL is described, focusing on loops and streams and on microtasking software. Performance results are reported for Livermore kernel 1, the Sieve prime finder, insertion sort, Batcher sort, the Simple hydrodynamics code, and the PSPhot photon-transport code     

A communication system for distributed computations on a network of personal computers

This paper deals with a software system PCCOM which makes it possible to simulate a distributed memory environment for parallel computations by using a local area network of personal computers. This system consists of FORTRAN subroutines that can be used from application programs. Parallel computations may be performed on a network of personal computers under DOS or any other operating system. This software package simulates, partially, the widespread PVM (Parallel Virtual Machine) package which runs under UNIX. A simple example of an application is given here.     

Concepts and implementation of parallel finite element analysis

The design of complex engineering systems such as advanced aircraft structures and offshore platforms requires continually increasing levels of detail in supporting analysis. The finite element method is widely used as a computational method with which to model physical systems in various engineering problems. For detailed analyses of complex designs, structural models composed of several thousands of degrees of freedom are no longer uncommon. Such design activities require large order finite element and/or finite difference models and excessive computation demands in both calculation speed and information management. The computer simulation of the nonlinear dynamic response of structures and the implementation of parallel FEM systems on a high speed multiprocessor have received considerable attention in recent years. The driving forces of these activities included the reliable simulation of automotive and aircraft crash phenomena, and the increased performance of computers. Most existing major structural analysis software systems were designed 10–20 years ago and have been optimized for current sequential computers. Such systems often are not well structured to take maximum advantage of the recent and continuing revolution in parallel vector computing capabilities. These parallel vector computer architectures not only occur in the form of large supercomputers, but are now also occurring for minicomputers and even engineering workstations. To benefit from advances in parallel computers, software must be developed which takes maximum advantage of the parallel processing feature.     

OCCAM solves classical operating system problems

Strictly sequential software is a thing of the past. The development of the OCCAM language, and of the Transputer for implementing it, has made parallel microprocessing a practical alternative to more traditional methods. The fundamentals of OCCAM are outlined. An OCCAM-based approach to solving a multiplexer problem is compared with a PASCAL-based approach. The advantages of replacing PASCAL constructs with OCCAM equivalents (eg semaphores with channels) are emphasized, OCCAM is seen as the herald of truly fifth-generation computers.     

并行油藏模拟软件的实现及在国产高性能计算机上的应用

主要介绍了百万网格点规模的精细油藏数值模拟在国产高性能并行计算机与微机机群系统上的应用情况 .针对若干组来自于国内油田的百万网格点实际数据 ,给出了在多种国产并行机环境下的运行结果 ,并作了分析与评价 .在此基础上 ,讨论并行油藏数值模拟软件高效实现过程中遇到的关键技术 ,探讨大型软件并行化过程中经常遇到的瓶颈问题及改进方案     

Porting industrial codes and developing sparse linear solvers on parallel computers

We address the main issues when porting existing codes from serial to parallel computers and when developing portable parallel software on MIMD multiprocessors (shared memory, virtual shared memory, and distributed memory multiprocessors, and networks of computers). We discuss the use of numerical libraries as a way of developing portable and efficient parallel code. We illustrate this by using examples from our experience in porting industrial codes and in designing parallel numerical libraries. We report in some detail on the parallelization of scientific applications coming from Centre National d'Etudes Spatiales and from Aérospatiale, and we illustrate how it is possible to develop portable and efficient numerical software by considering the parallel solution of sparse linear systems of equations.     

Testing Moderately Parallel Environments for an Ocean Modeling Application

Due to the high costs of accessing massively parallel and vector environments, as well as the overworking of high-performance computers, there is now a need for a different approach to parallel computing. The feasibility of ocean modeling in a moderately parallel environment is tested using a 2-D (vertically-integrated) ocean circulation model. The parallel algorithm is based on the Glenda message-passing software and follows the master-worker paradigm. It is evaluated on both internal and external communication environments. The numerical experiments show that the internal communication environment is only slightly more efficient than the external communication environment. This is due to a combination of shared memory problems in the internal communication environment and to inefficiencies in the message-passing software. The tests also demonstrate how efficiency depends on the domain sub-divisions. Most importantly, they show that both environments effectively outperform their sequential counterparts, reducing the program elapsed time, and offering quicker access to the model outputs. The parallel version provided a time-saving alternative to the sequential version of the same model on both internal and external communication platforms. This research supports the conclusion that both environments are a viable alternative to single-CPU machines and that moderately parallel environments are feasible computer platforms for ocean modeling applications.     

Multiprocessors from a software perspective

Like many architectural techniques that originated with mainframes. the use of multiple processors in a single computer is becoming popular in workstations and even personal computers. Multiprocessors constitute a significant percentage of recent workstation sales, and highly affordable multiprocessor personal computers are available in local computer stores. Once again, we find ourselves in a familiar situation: hardware is ahead of software. Because of the complexity of parallel programming, multiprocessors today are rarely used to speed up individual applications. Instead, they usually function as cycle-servers that achieve increased system throughput by running multiple tasks simultaneously. Automatic parallelization by a compiler is a particularly attractive approach to software development for multiprocessors, as it enables ordinary sequential programs to take advantage of the multiprocessor hardware without user involvement. This article looks to the future by examining some of the latest research results in automatic parallelization technology     

Parallel Programming of Multi-processor SoC: A HW–SW Interface Perspective

For the design of classic computers the parallel programming concept is used to abstract HW/SW interfaces during high level specification of application software. The software is then adapted to existing multiprocessor platforms using a low level software layer that implements the programming model. Unlike classic computers, the design of heterogeneous MPSoC includes also building the processors and other kind of hardware components required to execute the software. In this case, the programming model hides both hardware and software refinements. This paper deals with parallel programming models to abstract both hardware and software interfaces in the case of heterogeneous MPSoC design. Different abstraction levels will be needed. For the long term, the use of higher level programming models will open new vistas for optimization and architecture exploration like CPU/RTOS tradeoffs.     

A hardware and software environment for parallel processing with PCs

This paper describes the construction of a scientific parallel computer system using IBM compatible personal computers as the node processors; and the development of suitable system software which enables applications, such as molecular mechanics and molecular dynamics calculations, to be run on the parallel computer. Performance figures are given for molecular mechanics calculations. A major feature of the host and node processors is the use of multiple, low-cost, interprocessor communications links, which have hardware broadcasting facilities.     

A parallel procedure for nonlinear analysis of reinforced concrete three-dimensional frames

The paper discusses the parallelisation of complex three-dimensional software for nonlinear analysis of R/C buildings structures. It presents a comparative study for handling the nonlinear response in different parallel architectures. The nonlinear finite element model adopts a fiber decomposition approach for the cross-section of beam elements to capture nonlinear behavior of concrete. The parallelisation strategy is designed regarding three items: the numerical stability of the nonlinear procedure, the parallel sparse equation solver and the application on heterogeneous hardware: dedicated shared memory machines or clusters of networked personal computers.     

可视化并行编程环境P-GRADE浅析

从科学及工程应用的计算模拟，到商业应用的数据挖掘及事务处理等许多领域，并行计算已产生了巨大的影响。但当前并行软件滞后于并行算法和高性能计算机本身的发展，这对并行计算的推广和普及产生一定的影响。本文介绍一种方便易用的可视化并行程序集成开发环境P-GRADE，并详细分析了P-GRADE中的并行程序设计部分的支撑工具GRAPNEL语言和图形编辑器GRED。     

A computing framework for integrating interactive visualization in HPCC applications

Network-based concurrent computing and interactive data visualization are two important components in industry applications of high-performance computing and communication. We propose an execution framework to build interactive remote visualization systems for real-world applications on heterogeneous parallel and distributed computers. Using a dataflow model of a commercial visualization software AVS in three case studies, we demonstrate a simple, effective, and modular approach to couple parallel simulation modules into an interactive remote visualization environment. The applications described in this paper are drawn from our industrial projects in financial modeling, computational electromagnetics and computational chemistry. Copyright © 1999 John Wiley & Sons, Ltd.