: 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...

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...

. L Systems are a mathematical formalism originally designed to model the biological growth of plants. They are based upon a parallel rewriting mechanism. We show in this paper that there exists an equivalence between the class of D0L Systems and a particular construction of programs in the 81/2 declarative data-parallel language. 1 Introduction 81/2 is a declarative data-parallel language aimed at the simulation of dynamical systems. Its main structure is the fabric which is a stream [1, 2, 3] of collections [4]. The stream aspect of the fabric is used to describe the time axis of the simulation whereas the collection aspect of the fabric describe the space axis of the simulation. Because of space restrictions, we will not detail the 81/2 language here. The reader should refer to the paper "Introducing dynamicity in the data-parallel language 81/2" in these proceedings or to [5]. An 81/2 program is a set of equations defining the relations between the variables of the dynamical syst...

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