摘要:

AbstractExperiences are described of parallelizing a functional finite‐element program (written in Haskell) for the solution of computational fluid‐dynamics problems. A transformation prototyping approach using a system developed at the University of York, which simulates idealised parallel machines on a conventional sequential workstation, is presented. In this paper we demonstrate: (a) the relative simplicity of the functional approach for parallelizing a complex program compared with the conventional procedural approach; (b) the suitability of functional languages for prototyping parallel algorithms to improve an implementation; and (c) the considerable assistance provided by the simula

ISSN:0038-0644    

DOI:10.1002/spe.4380250902

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have designed and implemented a type inference algorithm for the SELFlanguage. The algorithm can guarantee the safety and disambiguity of message sends, and provide useful information for browsers and optimizing compilers.SELFfeatures objects with dynamic inheritance. This construct has until now been considered incompatible with type inference because it allows the inheritance graph to change dynamically. Our algorithm handles this by deriving and solving type constraints that simultaneously define supersets of both the possible values of expressions and of the possible inheritance graphs. The apparent circularity is resolved by computing a global fixed‐point, in polynomial time.The algorithm has been implemented and can successfully handle the SELFbenchmark programs, which exist in the ‘standard SELFworld’ of more than 40,000 lines of

ISSN:0038-0644    

DOI:10.1002/spe.4380250903

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe propose a methodology of reducing the space requirements of recursive procedures without destroying their fundamental recursive structure. This technique is quite general, and seems to apply to most recursive procedures, particularly those dealing with recursive data structures. A recursive procedure is transformed into three procedures — a shell which is called from the outside, and has the same interface as the original, a recursive procedure with a minimum number of parameters, and no local variables, and a procedure that performs the operations but has no recursive calls. Our methodology was successfully employed in an implementation of a decision support system. The paper also includes results of experiments, in which space was reduced by a factor of up to seven, and run time was also improve

ISSN:0038-0644    

DOI:10.1002/spe.4380250904

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractMultiple‐instruction‐issue processors seek to improve performance over scalar RISC processors by providing multiple pipelined functional units in order to fetch, decode and execute several instructions per cycle. The process of identifying instructions which can be executed in parallel and distributing them between the available functional units is referred to as instruction scheduling. This paper describes a simple compile‐time scheduling technique, called conditional compaction, which uses the concept of conditional execution to move instructions across basic block boundaries. It then presents the results of an investigation into the performance of the scheduling technique using C benchmark programs scheduled for machines with different functional unit configurations. This paper represents the culmination of our investigation into how much performance improvement can be obtained using conditional execution as the sole scheduling tech

ISSN:0038-0644    

DOI:10.1002/spe.4380250905

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractCommunication protocols used in the field have always suffered from failures. Some of these faults are the result of design errors; others are the result of implementation errors. These errors dramatically increase maintenance cost and decrease software reliability. The best time to maintain software is during its design stage. A formal approach to developing a protocol is deemed necessary to improve the quality of communication software and to reduce maintenance costs. Protocol verification plays a major role in achieving these objectives; a protocol is first specified formally and then this formal specification is analysed using a computer‐aided tool. PROTEAN is a software tool that verifies a protocol specified formally in Numerical Petri Nets. This paper describes the experience and practice of using PROTEAN to verify a complex protocol and then presents an evaluation of PROTEAN and its associated techniques in the light of protocol software development. The ISO FTAM protocol is used as a case stud

ISSN:0038-0644    

DOI:10.1002/spe.4380250906

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractBy referring to the object‐oriented efforts of the Multimedia and Hypermedia information coding Expert Group (MHEG), and the augmented Petri net model, we present a formal definition of the multimedia hypermedia Petri net (MHPN) model. Through this proposed model, issues of authoring, rendering and synchronization of multimedia information (i.e. structure authoring, spatial temporal relationships, user interaction, etc.) can all be laid to rest. We have implemented a testbed system, the Petri net object information system (POIS), which offers considerable potential for the development of distributed hypermedia applications. The testbed has been implemented on an IBM‐PC486 under Windows 3.1. We are now in the process of porting the testbed model to Windows

ISSN:0038-0644    

DOI:10.1002/spe.4380250907

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380250901

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY