N Floros

Load Balancing by Redundant Decomposition and Mapping

In this paper a methodology is presented that has been developed in the CAMAS3 project for the purpose of decomposition and mapping of parallel processes to processor topologies. The methodology has been implemented in terms of a toolset, thus allowing automatic decomposition and mapping of parallel processes. The parallel processes and processors are modelled according to a generally applicable formalism, based on the so-called virtual particle model. As a case study the presented methodology is applied to parallel finite element simulations.

Predictive resource management for meta-applications

This paper defines meta-applications as large, related collections of computational tasks, designed to achieve a specific overall result, running on a (possibly geographically) distributed, non-dedicated meta-computing platform. To carry out such applications in an industrial context, one requires resource management and job scheduling facilities (including capacity planning), to ensure that the application is feasible using the available resources, that each component job will be sent to an appropriate resource, and that everything will finish before the computing resources are needed for other purposes.

Comparative efficiencies of domain decompositions

Abstract We identify and compare two different classes of domain decomposition algorithms suitable for grid-based simulation programs, such as those commonly found in finite element and finite volume codes. The domain decomposition schemes are either, logical methods that only account for the connectedness of the grid, or physical methods that take account only of the spatial separation of grid points. We use Engineering Systems Internationals finite element PAM-CRASH code on a number of grids of varying size and complexity. The recursive spectral partitioning method (a logical method) is consistently better than all the other methods for small to medium sized grids, while the physical methods are marginally better for comparatively larger grid sizes.

Industrial Stochastic Simulations on a European Meta-Computer

This paper outlines the experiences of running a large stochastic multi-body simulation across a pan-European meta-computer, to demonstrate the use of the PROMENVIR tool within such a large-scale WAN environment. We describe the meta-application management approach developed by PAC and discuss the technical issues raised by this experiment.

Evaluation of a spectral element CFD code on parallel architectures

We present an evaluation of a Spectral Element Navier-Stokes solver on three generations of parallel architecture. The parallel platforms used are a network of Transputers, an Intel iPSC/860 and a Meiko CS2. While performance on the older Transputer and iPSC/860 machines is fairly predictable, the behaviour of the code on the SPARC-10 based Meiko CS2 demonstrated the influence of the internal memory hierachy on performance. These effects give the code problem dependent performance parameters that makes scaling properties difficult to quantify. Our code however, seems future proof, provided sufficiently large problems can be found to overcome the relatively large communications costs with respect to the processor speed.