This paper presents a new parallel algorithm in Molecular Dynamics simulation - HA (Hierarchical Algorithm). HA algorithm has two levels. Spatial decomposition strategy is used in the outer level to reduce the communi...
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ISBN:
(纸本)088986392X
This paper presents a new parallel algorithm in Molecular Dynamics simulation - HA (Hierarchical Algorithm). HA algorithm has two levels. Spatial decomposition strategy is used in the outer level to reduce the communication cost and improve the scalability;force decomposition strategy is used in the inner level to give a better load balance performance. When used to simulate a large nucleation system with non-uniform density, HA performs better than pure SD and FD algorithms.
Models of ATM communication systems were simulated on massively parallel SIMD computer. Fast simulations of ATM models are needed because the regimes of interest usually involve high volumes of traffic and low failure...
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Models of ATM communication systems were simulated on massively parallel SIMD computer. Fast simulations of ATM models are needed because the regimes of interest usually involve high volumes of traffic and low failure rates. Unexpected practical and theoretical difficulties, partly due to the massive parallelism and SIMD aspects, were encountered;this paper shows how to cope with them. In a replica-parallelsimulation of an ATM system, large variations in computed statistics are caused by small differences in the distribution of employed random number generators. A comparison of these distributions using a secondary statistical measure served to disambiguate the results.
We investigated the benefit of exploiting the symmetries of graphs for partitioning. We represent the model to be simulated by a weighted graph. Graph symmetries are studied in the theory of permutation groups and can...
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ISBN:
(纸本)0769521118
We investigated the benefit of exploiting the symmetries of graphs for partitioning. We represent the model to be simulated by a weighted graph. Graph symmetries are studied in the theory of permutation groups and can be calculated in polynomial time with the nauty algorithm [15]. We designed an algorithm to extract useful symmetries from the automorphism group, which can be used to create partitions derived from the graph's structure. Our approach is focused on composite graphs, for which identical subgraphs reoccur in the graph. If these identical subgraphs can be mapped onto each other by symmetries, the subgraphs are replaced by equivalent multivertices, resulting in a 'natural' aggregation of vertices. This approach is applied to parallelsimulation of a detailed IP-switch with a conservative synchronous algorithm. The experimental results show that even for good partitions, global and temporal load imbalances are inevitable.
We describe a model for an interdisciplinary course in scientific modeling and simulation. We discuss the course structure and content, as well as the results of our evaluation process.
ISBN:
(纸本)0769522947
We describe a model for an interdisciplinary course in scientific modeling and simulation. We discuss the course structure and content, as well as the results of our evaluation process.
In this paper an approach to provide Web-based framework for distributed execution of collaborative applications is presented. The work is a part of a wider on-going project whose aim is to make environmental simulati...
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ISBN:
(纸本)0818680431
In this paper an approach to provide Web-based framework for distributed execution of collaborative applications is presented. The work is a part of a wider on-going project whose aim is to make environmental simulation models publicly available to the Internet users. The Web computing skeleton has been constructed from prefabricated Web-enabled components with the ability to open and maintain Web connections and provide collaboration over the Internet. The case study illustrates how a single-user simulation system can be embedded in the skeleton, thus becoming widely available distributed application.
In this work we focus on a new technique for making cloning of parallelsimulations more efficient. Cloning provides a means for running multiple similar simulations in parallel where many computations are shared rath...
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ISBN:
(纸本)0769521118
In this work we focus on a new technique for making cloning of parallelsimulations more efficient. Cloning provides a means for running multiple similar simulations in parallel where many computations are shared rather than repeated [12]. A simulation is cloned on an event for a particular set of logical processes, creating new LP clones. The clones diverge as messages from the new LPs arrive at uncloned LPs. Until replication, all the computations for a particular LP are shared between the clones. simulation kernels using cloning achieve efficiency by incrementally replicating logical processes as necessary. This enables regions of the simulation that have not been affected to use the same computations for both the new and old clone. Clearly, the longer replication can be delayed, the more efficient the simulation. We hypothesize that in many cases replication takes place before it is strictly necessary. We propose just-in-time cloning that addresses this issue by relaxing the constraints of simulation cloning to further benefit from shared computations.
The partitioning of systems for parallelsimulation is a complex task, requiring consideration of both computational load requirements and communications activity. Typically, this information is not accurately known p...
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The partitioning of systems for parallelsimulation is a complex task, requiring consideration of both computational load requirements and communications activity. Typically, this information is not accurately known prior to execution. This paper investigates the use of historical information for the prediction of future requirements, both for computation and communications. In addition, for optimistic simulation algorithms, we present a novel technique (which we call predictive optimism) whereby binary prediction schemes can be used to increase the accuracy of optimistic assumptions, thereby decreasing rollbacks and potentially improving overall simulator performance.
This paper describes an approach to discrete event simulation modeling that appears to be effective for developing portable and efficient parallel execution of models of large distributed systems and communication net...
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This paper describes an approach to discrete event simulation modeling that appears to be effective for developing portable and efficient parallel execution of models of large distributed systems and communication networks. In this approach, the modeler develops sub-models using an existing sequential simulation modeling tool, using the full expressive power of the tool. A set of modeling language extensions permit automatically synchronized communication between sub-models;however, the automation requires that any such communication must take a non-zero amount of simulation time. Within this modeling paradigm, a variety of conservative synchronization protocols can transparently support conservative execution of sub-models on potentially different processors. A specific implementation of this approach, U.P.S. (Utilitarian parallel Simulator), is described, along with performance results on the Intel Paragon.
The proceedings contain 70 papers. The topics discussed include: programming shared virtual memory multiprocessors;parallelsimulation of a multi-dimensional computational fluid dynamics problem;computing the singular...
ISBN:
(纸本)0818673761
The proceedings contain 70 papers. The topics discussed include: programming shared virtual memory multiprocessors;parallelsimulation of a multi-dimensional computational fluid dynamics problem;computing the singular values of the product of two matrices in distributed memory multiprocessors;a latency-hiding MIMD wavelet transform;simulation of chaotic iterative processes in speed-independent computing networks;sparse householder QR factorization on a mesh;and the role of associative memory in virtual shared memory architectures: a price-performance comparison.
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