The diversity and complexity of parallel computers (both proposed and 
implemented) drives the quest for portable, tractable and efficiently
implementable parallel programming models and languages. One approach
to the problem focuses upon the design and exploitation of 
higher order  programming and algorithmic constructs which can
become the fundamental building blocks in such a model. An analogy can
be drawn with the historical development of sequential programming, 
in which simple, relatively  unstructured mechanisms, closely tied
to the underlying architecture, have given way to more powerful, 
structured and abstract concepts. Similar progress in the parallel
case would raise the level of abstraction from models in which
simple communications (or similar) are primitive to a world in which
more complex patterns of computation and interaction are combined
and presented as parameterized higher order program-forming constructs.

<p>

There are three more or less interwoven threads of research in the area.
Work on Algorithmic Skeletons focuses on the selection and implementation
of appropriate primitives (the `skeletons'), typically with a bias towards
coarse-grain primitives and control-parallel implementation. Researchers in 
Program Development apply and extend techniques from the sequential branch
of the field to the parallel case, developing new design methodologies
and models in which, as discussed above, the level of abstraction is
raised from the base level of simple concurrent activities, and in
which there are facilities for understanding the cost of the program
under development during its design. The final thread seeks to design
and understand the formal models which underpin the area, whether by
viewing existing models in a parallel light (for example, work on
the Bird-Meertens Formalism as a parallel programming model) or by
developing new ones. Much work in this thread takes a more data-parallel 
view of the process. 


<p>

The concerns spanned by these groups
range from the very pragmatic questions of implementation techniques
and real applications to the abstract world of formal program development.
Many researchers from all of the areas had already been brought together
electronically, via e-mail lists and WWW pages.
The seminar was an opportunity to establish the community and intensify
the contacts.

<p>


Questions discussed at the seminar included:
<ul>
  <li> Which primitives are suitable for a parallel programming model?
  <li> Can the selection of primitives be justified pragmatically
        and/or theoretically?
  <li> To what extent should the parallelism within the primitives
        be apparent to the programmer?
  <li> To what extent can and should the implementation mechanisms attempt to 
        optimize the parallel structure of composed primitives?
  <li> To what extent can this optimization be reflected in a compositional cost
        model (or cost calculus)?
  <li> To what extent do `sequential' techniques in program development
        shed light on the parallel case?
  <li> What are the new transformations for the new primitives?
  <li> How well does the approach compare with conventional models
        in its ability to express `classical' parallel
        algorithms and to derive new ones?
</ul>


The 43 participants of the workshop came from 10 countries: 16 from
Germany, 8 from the UK, 6 from the USA, 5 from France, 2 from Italy
and 1 from each Australia, Canada, Japan, New Zealand and Sweden. 
The organizers would like
to thank everyone who has helped to make this workshop a success.

<p>

Murray Cole,   Sergei Gorlatch,  Christian Lengauer, David Skillicorn