A Pure Java Parallel Flow Solver

In this paper an overview is given on the "Have Java" project to attain a pure Java parallel Navier-Stokes flow solver (JParNSS) based on the thread concept and remote method invocation (RMI). The goal of this project is to produce an industrial flow solver running on an arbitrary sequential or parallel architecture, utilizing the Internet, capable of handling the most complex 3D geometries as well as flow physics, and also linking to codes in other areas such as aeroelasticity etc. Since Java is completely object-oriented the code has been written in an object-oriented programming (OOP) style. The code also includes a graphics user interface (GUI) as well as an interactive steering package for the parallel architecture. The Java OOP approach provides profoundly improved software productivity, robustness, and security as well as reusability and maintainability. OOP allows code construction similar to the aerodynamic design process because objects can be software coded and integrated, reflecting actual design procedures. In addition, Java is the programming language of the Internet and thus Java is the programming language of the Internet and thus Java objects on disparate machines or even separate networks can be connected. We explain the motivation for the design of JParNSS along with its capabilities that set it apart from other solvers. In the first two sections we present a discussion of the Java language as the programming tool for aerospace applications. In section three the objectives of the Have Java project are presented. In the next section the layer structures of JParNSS are discussed with emphasis on the parallelization and client-server (RMI) layers. JParNSS, like its predecessor ParNSS (ANSI-C), is based on the multiblock idea, and allows for arbitrarily complex topologies. Grids are accepted in GridPro property settings, grids of any size or block number can be directly read by JParNSS without any further modifications, requiring no additional preparation time for the solver input. In the last section, computational results are presented, with emphasis on multiprocessor Pentium and Sun parallel systems run by the Solaris operating system (OS)

A Test Suite for High-Performance Parallel Java

The Java programming language has a number of features that make it attractive for writing high-quality, portable parallel programs. A pure object formulation, strong typing and the exception model make programs easier to create, debug, and maintain. The elegant threading provides a simple route to parallelism on shared-memory machines. Anticipating great improvements in numerical performance, this paper presents a suite of simple programs that indicate how a pure Java Navier-Stokes solver might perform. The suite includes a parallel Euler solver. We present results from a 32-processor Hewlett-Packard machine and a 4-processor Sun server. While speedup is excellent on both machines, indicating a high-quality thread scheduler, the single-processor performance needs much improvement

JavaGrid: An Innovative Software for HPCC

In this paper we describe the JavaGrid concept that underlies the software developed for high performance computing and communication in science and engineering. JavaGrid provides a package for parallelization based on Java threads, a geometry package for handling 2D and 3D structured as well as unstructured grids, a generic solver and a solver template to model a system of integral conservation laws. JavaGrid provides both client and server software and allows to send a specific solver at run time from the client to the server, overriding the server's default solver. For instance, this might be a computational fluid dynamics solver, while the client wishes to execute an electrodynamics solver.\ud However, both solvers could be based on the template solver provided. Setting up a new solver is a straightforward process, since only the physics equations have to be implemented for a single subdomain. Geometry handling, parallelzation (i.e. updating the boundary of neighboring subdomains) and communication is handled by JavaGrid. It is also possible to incorporate so called legacy solvers, written in other languages. A Virtual Visualization toolkit for remote visualization is also provided. The paper describes the current status of the JavaGrid project and presents performance figures

Aerodynamic Simulation on Massively Parallel Systems

This paper briefly addresses the computational requirements for the analysis of complete configurations of aircraft and spacecraft currently under design to be used for advanced transportation in commercial applications as well as in space flight. The discussion clearly shows that massively parallel systems are the only alternative which is both cost effective and on the other hand can provide the necessary TeraFlops, needed to satisfy the narrow design margins of modern vehicles. It is assumed that the solution of the governing physical equations, i.e., the Navier-Stokes equations which may be complemented by chemistry and turbulence models, is done on multiblock grids. This technique is situated between the fully structured approach of classical boundary fitted grids and the fully unstructured tetrahedra grids. A fully structured grid best represents the flow physiscs, while the unstructured grid gives best geometrical flexiblity. The multiblock grid employed is structured within a block, but completely unstructured on the block level. While a completely unstructured grid is not straightforward to parallelize, the above mentioned multiblock grid is inherently parallel, in particular for MIMD machines. In this paper guidelines are provided for setting up or modifying an existing sequential code so that a direct parallelization on a massively parallel system is possible. Results are presented for three parallel systems, namely the Intel hypercube, the Ncube hypercube, and the FPS 500 system. Some preliminary results for an 8K CM2 machine will also be mentioned. The code run is the 2D grid generation module of Grid *, which is a general 2D and 3D grid generation code for complex geometries. A system of nonJjnear Poisson equations is solved. This code is also a good testcase for complex fluid dynamics codes, since the same datastructures are used. All systems provided good speedups, but message passing MIMD systems seem to be best suited for large multiblock applications