: 81/2 is a declarative data-parallel language designed for the simulation of large dynamical systems. Such simulations are of growing importance and they requires more and more computing power. In consequence, 81/2 introduces a new entity, the web, that combines features of collection-oriented and data-flow language to express data-, stream- and control-parallelism. In this paper, we present the language 81/2, some examples of dynamical systems programmed in 81/2 and we describe the compilation process of a 81/2 programme. Key-words: data-parallelism, collection-oriented languages, declarative languages, synchronous data-flow languages, simulation of dynamical systems. I. Introduction Nowadays, simulation of large dynamical systems represents the majority of supercomputers applications. In this article, a dynamical system refers as any application that modelizes space-time phenomena. Three usual examples are: . numerical resolution of partial differential equations [1] describing con...

This paper describes the language 8 1/2 , an embedding of data-parallelism in a declarative framework.

. The main motivation of 81/2 is to develop a high-level language that supports the parallel simulation of dynamical processes [1, 2]. To achieve this goal, a new data-structure, that merges the concept of stream and collection is introduced in a declarative framework. After a brief description of 81/2 basics, we describe the introduction of dynamicity and symbolic values in the language. We focus on the expressivity and issues brought by the new dynamic possibilities of the language and show, through several paradigmatic examples, that our computation model is able to support parallel symbolic processing. 1 The Declarative Data-Parallel Language 81/2 1.1 Motivations: the Implicit Data-Parallel Approach to Parallel Symbolic Processing 81/2 is an experimental language combining features of collection and stream oriented languages in a declarative framework. It tries to promote the construction of parallel programs by isolating the programmer from the complexities of parallel proces...

81/2 is a data-parallel language that relies on the notions of stream and collection in a high-level declarative framework. We describe in this research report semantics and compilation of sequential streams of collections for this language. Firstly, a denotational semantics is associated with recursively defined sequential 81/2 streams. Furthermore, we explain how the fixed point calculus corresponding to the foregoing semantics is implemented. Secondly, we describe an effective code generation scheme targetted towards either sequential, vector or SIMD architectures. Then we present four optimization processes for the generated code: the sharing of common control expressions, the optimization of delay copies, the loop fusion and the concatenation optimization. Next, some elements for the evaluation of the generated code are given. As a conclusion, we recall the overall effectiveness of the stream compilation and draw the future work. Key-words: stream, compilation of data-flow graphs...

We describe FieldBroker, a software architecture, dedicated to data parallel computations on fields over Z n . Fields are a natural extension of the parallel array data structure. From the application point of view, field operations are processed by a field server, leading to a client/server architecture. Requests are translated successively in three languages corresponding to a tower of three virtual machines processing respectively mappings on Z n , sets of arrays and flat vectors in core memory. The server is itself designed as a master/multithreaded-slaves program. The aim of FieldBroker is to mutually incorporate approaches found in distributed computing, functional programming and the data parallel paradigm. It provides a testbed for experiments with language constructs, evaluation mechanisms, on-the-fly optimizations, load-balancing strategies and data field implementations. Keywords: distributed computing, data parallel computing, data field, virtual machine, software arch...

We advocate a data-flow approach to data-parallelism to ensure both parallelism expressiveness and efficient exploitation of data-parallel applications on new massively parallel architectures. The rational of this approach is introduced in the first part of the paper. Then we develop an experimental language following these lines and sketch the techniques used to compile such a data-flow data-parallel language. Its compilation, based upon a static execution model enabling an efficient execution of programs, is introduced. 1. The Parallelism and its Expression Through Data 1.1. A Short Taxonomy of Parallelism Expression in Programming Languages The many existing models and languages for parallel programming lead to an overlap of concepts making the design of a taxonomy a hard task. However, we propose in table 1 a framework used to specify the concepts presented in this paper. Two criteria have been selected to classify the languages: the way they let the programmer express control an...

8 ½, an experimental language combining features of collection and stream oriented languages...

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