This paper presents the software architecture and implementation of the problem solving

In this paper we review the current state of the problem solving environment (PSE) field and make projections for the future. First we describe the computing context, the definition of a PSE and the goals of a PSE. The state-of-the-art is summarized along with sources (books, bibliographics, web sites) of more detailed information. The principal components and paradigms for building PSEs are presented. The discussion of the future is given in three parts: future trends, scenarios for 2010/2025, and research

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. This paper describes two projects underway to provide users with access to high performance computing technologies. One effort, the National HPCC Software Exchange, is providing a single point of entry to a distributed collection of domain-specific repositories. These repositories collect, catalog, evaluate, and provide access to software in their specialized domains. The NHSE infrastructure allows these repositories to interoperate with each other and with the top-level NHSE interface. Another effort is the NetSolve project which is a client-server application designed to solve computational science problems over a network. Users may access NetSolve computational servers through C, Fortran, MATLAB, or World Wide Web interfaces. An interesting intersection between the two projects would be the use of the NetSolve system by a domain-specific repository to provide access to software without the need for users to download and install the software on their own systems. 1 The National HPC...

this paper we explore an approach which enables all of the problems listed above to be solved at a single stroke: use Lisp as the source language for the numeric and graphical code! This is not a new idea --- it was tried at MIT and UCB in the 1970's. While these experiments were modestly successful, the particular systems are obsolete. Fortunately, some of those ideas used in Maclisp [37], NIL [38] and Franz Lisp [20] were incorporated in the subsequent standardization of Common Lisp (CL) [35]. In this new setting it is appropriate to re-examine the theoretical and practical implications of writing numeric code in Lisp. The popular conceptions of Lisp's inefficiency for numerics have been based on rumor, supposition, and experience with early and (in fact) inefficient implementations. It is certainly possible to continue to write inefficient programs: As one example of the results of de-emphasizing numerics in the design, consider the situation of the basic arithmetic operators. The definitions of these functions require that they are generic, (e.g. "+" must be able to add any combination of several precisions of floats, arbitrary-precision integers, rational numbers, and complexes), The very simple way of implementing this arithmetic -- by subroutine calls -- is also very inefficient. Even with appropriate declarations to enable more specific treatment of numeric types, compilers are free to ignore declarations and such implementations naturally do not accommodate the needs of intensive number-crunching. (See the appendix for further discussion of declarations). Be this as it may, the situation with respect to Lisp has changed for the better in recent years. With the advent of ANSI standard Common Lisp, several active vendors of implementations and one active universi...

This paper describes an extension of the ebXML registry for publishing and discovering mathematical service descriptions. The MathBroker registry is able to handle descriptions given in the Mathematical Service Description Language, a language designed ad-hoc for capturing the semantics of web services dealing with mathematical problems. The registry is distributed with a Java API implementing a MathBroker specific JAXR provider. 1.

This paper addresses the optimal control problem of timed continuous Petri nets under infinite servers semantics. In particular, our goal is to find a control input optimizing a certain cost function that permits the evolution from an initial marking (state) to a desired steady-state. The solution we propose is based on a particular discrete-time representation of the controlled continuous Petri net system, as a certain linear constrained system. An upper bound on the sample period is given in order to preserve important information of the timed continuous net, in particular the positiveness of the markings. The reachability space of the sampled system in relation to autonomous continuous Petri nets is also studied. Based on the resulting linear constrained model, the optimal control problem is studied through Model Predictive Control (MPC). Implicit and explicit procedures are presented together with a comparison between the two schemes. Stability of the closed-loop system is also studied.

Selecting the right numerical solver or the most appropriate numerical package for a particular simulation problem it is increasingly difficult for users without an extensive mathematical background and deeper knowledge in numerical analysis. In this paper we propose a model-driven combined decision-simulation framework for automatically selecting a numerical method for a given set of equation system. We also propose a formal paradigm based on domain-specific languages for specification of structural and behavioral aspects of the numerical equation solving process. Starting from a declarative description of the equation system that need to be solved, our system is able to detect the nature of the equations, perform symbolic manipulations of the equations, and transform them into a domain-specific model. We describe the motivation for such a system, its main features, and a prototype environment together with a usage example.

Embedding robust and efficient algorithms in high-quality reusable software is an effective means of transferring the expertise of mathematicians to researchers in other disciplines, and a wealth of such software is already available. Unfortunately, its volume and distribution over labyrinthine computer networks makes it difficult for users to locate appropriate tools. The Guide to Available Mathematical Software (GAMS) is network-based cross-index and virtual repository that provides scientists and engineers with convenient access to such software. GAMS currently indexes some 9000 problem-solving software modules from some 80 packages distributed among four Internet-accessible software repositories. This software is cross-indexed using the widely-adopted GAMS problem classification system. In addition, GAMS provides on-demand redistribution of such objects as abstracts, documentation, and source code of software that it catalogs. The system is based on a client-server architecture uti...