Field programmable gate arrays containing more than one size of lookup-table occupy a large and growing portion of the market, but technology mapping for these architectures has hardly been considered. New algorithms ...
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Field programmable gate arrays containing more than one size of lookup-table occupy a large and growing portion of the market, but technology mapping for these architectures has hardly been considered. New algorithms have been developed for decomposition, covering and restructuring targeted at these architectures. Benchmark results show that the new method produces circuits which are on average 15% smaller than the best previous approach we know of.
With two examples we show the suitability of the bulk-synchronous parallel (BSP) model for discrete-event simulation of homogeneous large-scale systems. This model provides a unifying approach for general purpose para...
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ISBN:
(纸本)0818679654
With two examples we show the suitability of the bulk-synchronous parallel (BSP) model for discrete-event simulation of homogeneous large-scale systems. This model provides a unifying approach for general purpose parallel computing which in addition to efficient and scalable computation, ensures portability across different parallel architectures. A valuable feature of this approach is a simple cost model that enables precise performance prediction of BSP algorithms. We show both theoretically and empirically that systems with uniform event occurrence among their components, such as colliding hard-spheres and ising-spin models, can be efficiently simulated in practice on current parallel computers supporting the BSP model.
The two models presented in this paper provide two different semantics for an extension of Dijkstra's language of guarded commands. The extended language has an additional operator, namely probabilistic choice, wh...
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The two models presented in this paper provide two different semantics for an extension of Dijkstra's language of guarded commands. The extended language has an additional operator, namely probabilistic choice, which makes it possible to express randomized algorithms. An earlier model by Claire Jones included probabilistic choice but not non-determinism, which meant that it could not be used for the development of algorithms from specifications. Our second model is built on top of Claire Jones' model, using a general method of extending a probabilistic cpo to one which also contains non-determinism. The first model was constructed from scratch, as it were, guided only by the desire for certain algebraic properties of the language constructs, which we found lacking in the second model. We compare and contrast the properties of the two models both by giving examples and by constructing mappings between them and the non-probabilistic model. On the basis of this comparison we argue that, in general, the first model is preferable to the second. (C) 1997 Elsevier Science B.V.
We describe and analyse a new parallel algorithm for event-driven simulation of hard-particle systems that is based on the ideas of the bulk-synchronous parallel (BSP) model. This model provides a unifying approach fo...
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We describe and analyse a new parallel algorithm for event-driven simulation of hard-particle systems that is based on the ideas of the bulk-synchronous parallel (BSP) model. This model provides a unifying approach for general purpose parallel computing which in addition to efficient computation ensures portability across different parallel architectures. The hard-particle system is divided into regions that are owned by a unique processor. Events involving particles located in the region boundaries are called border zone events and are used to synchronize the parallel operation of the processors. On a P-processor BSP computer the algorithm works doing iterations composed of two phases: the parallel phase where each processor is simultaneously allowed to simulate serially and asynchronously its own region, and the synchronization phase where the occurrence of at most P border zone events is scheduled for the next iteration considering the state of neighboring regions. We show that this algorithm is efficient in practice provided that a sufficiently large hard-particle system is to be simulated.
Compositional proof systems for shared variable concurrent programs can be devised by including the interference information in the specifications. The formalism falls into a category called rely-guarantee (or assumpt...
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Compositional proof systems for shared variable concurrent programs can be devised by including the interference information in the specifications. The formalism falls into a category called rely-guarantee (or assumption-commitment), in which a specification is explicitly (syntactically) split into two corresponding parts. This paper summarises existing work on the rely-guarantee method and gives a systematic presentation. A proof system for partial correctness is given first, thereafter it is demonstrated how the relevant rules can be adapted to verify deadlock freedom and convergence. Soundness and completeness, of which the completeness proof is new, are studied with respect to an operational model. We observe that the rely-guarantee method is in a sense a reformulation of the classical non-compositional Owicki & Gries method, and we discuss throughout the paper the connection between these two methods.
With two examples we show the suitability of the bulk-synchronous parallel (BSP) model for discrete-event simulation of homogeneous large-scale systems. This model provides a unifying approach for general purpose para...
详细信息
ISBN:
(纸本)9780818679650
With two examples we show the suitability of the bulk-synchronous parallel (BSP) model for discrete-event simulation of homogeneous large-scale systems. This model provides a unifying approach for general purpose parallel computing which in addition to efficient and scalable computation, ensures portability across different parallel architectures. A valuable feature of this approach is a simple cost model that enables precise performance prediction of BSP algorithms. We show both theoretically and empirically that systems with uniform event occurrence among their components, such as colliding hard-spheres and ising-spin models, can be efficiently simulated in practice on current parallel computers supporting the BSP model.
This paper presents bulk-synchronous parallel (BSP) algorithms for linear system solving through QR and QZ factorisation. The two new algorithms are analysed in terms of the BSP cost model, and portable implementation...
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This paper presents bulk-synchronous parallel (BSP) algorithms for linear system solving through QR and QZ factorisation. The two new algorithms are analysed in terms of the BSP cost model, and portable implementations of the QR and QZ decomposition methods are devised using the Oxford BSP Library. The experimental results obtained on a shared-memory multiprocessor accurately match the theoretical predictions, permitting a thorough comparison of the two algorithms.
General purpose parallel computing systems come in a variety of forms. We have various kinds of distributed memory architectures, shared memory multiprocessors, and clusters of workstations. New technologies may incre...
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General purpose parallel computing systems come in a variety of forms. We have various kinds of distributed memory architectures, shared memory multiprocessors, and clusters of workstations. New technologies may increase this range still further. Can one hope to design portable and scalable parallel software in the face of such architectural diversity? In this paper we show that it is indeed possible to produce fully portable parallel software which will run with highly efficient, scalable and predictable performance on any general purpose parallel architecture. The approach we describe is based on the bulk synchronous parallel (BSP) model of computation. The BSP model provides a simple, unified framework for the design and programming of all kinds of general purpose parallel systems. Over the last few years, a number of important research activities in algorithms and architectures have been pursued as part of this new approach to scalable parallel computing. In this paper we give some simple BSP algorithms and show how they can be expressed as programs. We also briefly describe some of the BSP programming language developments which are now being pursued.
One of the concepts from topology that has found use in image processing is the so called Fundamental Group of an image. A definition for the digital fundamental group of a binary picture was introduced by Kong in A d...
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One of the concepts from topology that has found use in image processing is the so called Fundamental Group of an image. A definition for the digital fundamental group of a binary picture was introduced by Kong in A digital fundamental group [4]. This paper introduces a fundamental group for greyscale images. We also describe Poincare's classical method for computing a representation of the fundamental group and extend this to work with our greyscale version.
We present a very general language for expressing tactic programs. The paper describes some essential tactic combinators (tacticals), and gives them a formal semantics. Those definitions are used to produce a complete...
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We present a very general language for expressing tactic programs. The paper describes some essential tactic combinators (tacticals), and gives them a formal semantics. Those definitions are used to produce a complete calculus for reasoning about tactics written in this language. The language is extended to cover structural combinators which enable the tactics to be precisely targeted upon particular sub-expressions.
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