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\begin{document}
\title{
A Compositional Approach to Graphically Based Parallel
Programming%
\footnotemark[1]
}
\author{
J.C. Browne, J.Werth, Ravi Jain, Peter Newton\\
\\
Department of Computer Sciences\\
University of Texas, Austin, Texas 78712\\
browne@cs.utexas.edu 512-471-9579
}
\footnotetext[1]{
Paper to appear in {\it Proc. 26th Hawaii Intl. Conf.
Sys. Sci.}, Hawaii, Jan. 1993.
}
\date{}
\maketitle
\begin{centering}
\section*{Abstract}
\end{centering}
CODE (Computationally Oriented Display Environment)
[BRO89] is a graphical parallel programming environment
which is based on a formal model of parallel computation.
This model of parallel computation defines units of
computation and relationships among units of computation.
In the graphical environment the units of computation are
annotated nodes in a hypergraph and the relationships are
specified as annotated arcs or hyperarcs. Basing the
programming language on a formal model of computation leads
to the possibility of an alternative representation for
parallel computation structures. The interface
specifications for nodes (units of computation) can be
regarded as data structures to which compositional
operators can be applied. The compositional operators
carry the same information as the annotated arcs and
hyperarcs. A program becomes an algebraic expression over
the units of computation which evaluates to a parallel
program. The precise analogy is that a compositional
expression evaluates to a generalized dependency graph in
the CODE representation.
Several aspects of this
representation of parallel programs are of interest: (i)
It is complementary to the graphical display representation
since it is a compact means of specification of complex
structures which are not under direct study or analysis and
(ii) it strongly enforces a component oriented approach to
programming since the composition operators can act only on
the interfaces of the units of composition.
The full paper will define the model of parallel
computation and the calculus of composition which results
and illustrates the use of this alternative mode of
representation for parallelism. It will also compare this
approach to compositional programming to others which have
been proposed, for example [CHA91], and others.
{\bf References}
[BRO89] Browne, J.C., Sobek, S and Azam, M., CODE, A
Graphical Parallel Programming Environment, {\it
IEEE Software}, July, 1989.
[CHA91] Chandy, K.M. and Taylor, S.J., {\it An
Introduction to
Parallel Programming}, Jones and Bartlett, Boston, 1991.
\end{document}