Fortran M is a small set of extensions to Fortran 77 that supports a modular approach to the design of message-passing programs. It has the following features. (1) Modularity. Programs are constructed by using explicitly-declared communication channels to plug together program modules called processes. A process can encapsulate common data, subprocesses, and internal communication. (2) Safety. Operations on channels are restricted so as to guarantee deterministic execution, even in dynamic computations that create and delete processes and channels. Channels are typed, so a compiler can check for correct usage. (3) Architecture Independence. The mapping of processes to processors can be specified with respect to a virtual computer with size and shape different from that of the target computer. Mapping is specified by annotations that influence performance but not correctness. (4) Efficiency. Fortran M can be compiled efficiently for uniprocessors, sharedmemory computers, distributed-m...

Multicast communication services, in which the same message is delivered from a source node to an arbitrary number of destination nodes, are being provided in new generation multicomputers. Broadcast is a special case of multicast in which a message is delivered to all nodes in the network. The nCUBE-2, a wormhole-routed hypercube multicomputer, provides hardware support for broadcast and a restricted form of multicast in which the destinations form a subcube. However, the broadcast routing algorithm adopted in the nCUBE-2 is not deadlock-free. In this paper, four multicast wormhole routing strategies for two-dimensional (2D) mesh multicomputers are proposed and studied. All of the algorithms are shown to be deadlock-free. These are the first deadlock-free multicast wormhole routing algorithms ever proposed. A simulation study has been conducted that compares the performance of these multicast algorithms under dynamic network traffic conditions in a 2D mesh. The results ind...

Even though impressive progress has been made...

this article we discuss the design goals and decisions that determined the final form of Jade and present an overview of the Jade implementation. We also present our experience using Jade to implement several complete scientific and engineering applications. We use this experience to evaluate how the different Jade language features were used in practice and how well Jade as a whole supports the process of developing parallel applications. We find that the basic idea of preserving the serial semantics simplifies the program development process, and that the concept of using data access specifications to guide the parallelization offers significant advantages over more traditional control-based approaches. We also find that the Jade data model can interact poorly with concurrency patterns that write disjoint pieces of a single aggregate data structure, although this problem arises in only one of the applications. Categories and Subject Descriptors: D.1.3 [Programming Te

This paper describes the functionality of ViC*, a compiler-like preprocessor forout-of core C*. The input to ViC* is a C * program but with certain shapes declared outofcore, which means that all parallel variables of these shapes reside on disk. The output is a standard C* program with the appropriate I/O and library calls added for efficient access to out-of-core parallel variables.

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Compared to standard numerical methods for initial value problems (IVPs) for ordinary differential equations (ODEs), validated (also called interval) methods for IVPs for ODEs have two important advantages: if they return a solution to a problem, then (1) the problem is guaranteed to have a unique solution, and (2) an enclosure of the true solution is produced. To date, the only effective approach for computing guaranteed enclosures of the solution of an IVP for an ODE has been interval methods based on Taylor series. This thesis derives a new approach, an interval Hermite-Obreschkoff (IHO) method, for computing such enclosures. Compared to interval Taylor series (ITS) methods, for the same order and stepsize, our IHO scheme has a smaller truncation error and better...

Despite their vast deployment, distributed memory multiprocessors (DMM) still remain dicult to program, this is why portable and ecient languages are denitely needed. For the time being, parallelization tools like PVM provides a widely portable solution for low-level (explicit communications) programming. But PVM programs (C or Fortran with send and receive for communications) are hard to write and debug because of their undeterministic behaviors and rudimentary communication support. We propose an intermediate-level functional language called Caml Flight, which integrate a programming technique used by PVM programmers and featured in MPI. Right now, Caml Flight allows to write deterministic SPMD programs more easily. A long term goal is to be act as a target language for compilers of high-level languages. 1

A finite element method for computational fluid dynamics has been implemented on the Connection Machine systems CM-2 and CM-200. An implicit iterative solution strategy, based on the preconditioned matrix-free GMRES algorithm, is employed. Parallel data structures built on both nodal and elemental sets are used to achieve maximum parallelization. Communication primitives provided through the Connection Machine Scientific Software Library substantially improved the overall performance of the program. Computations of three-dimensional compressible flows using unstructured meshes having close to one million elements, such as a complete airplane, demonstrate that the Connection Machine systems are suitable for these applications. Performance comparisons are also carried out with the vector computers Cray Y-MP and Convex C-1. ii Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2. T...

In today’s widely used parallel programming models, subtle programming errors can lead to unintended nondeterministic behavior and hard to catch bugs. In contrast, we argue for a parallel programming model that is deterministic by default: deterministic behavior is guaranteed unless the programmer explicitly uses nondeterministic constructs. This goal is particularly challenging for modern object-oriented languages with expressive use of reference aliasing and updates to shared mutable state. We propose a broad research agenda in support of this goal, and we describe some of our own work to further that agenda. 1