Descriptive Simplicity in Parallel Computing


                          Marcus Marr

The programming of parallel computers is recognised as being a 
difficult task and there exist a wide selection of parallel
programming languages and environments. This thesis presents 
and examines the Hierarchical Skeleton Model (HSM), a model 
of parallel programming that combines ease of use, portability 
and flexibility.

The model is based on the exploitation of nested parallelism
in parallel algorithms expressed using a hierarchy of algorithmic
skeletons. The model acknowledges that not all forms of parallelism
can be expressed clearly using skeletons and allows the use of 
ad hoc parallelism within the controlled framework of the skeleton
hierarchy.

The thesis describes the HSM model and defines the syntax and
semantics of the HSM language. The model and language are evaluated
using three problems and compared against solutions written using the
Fork95++ language in a shared memory environment and the C++ language
with the Message Passing Interface (MPI) in a distributed memory 
environment.

The thesis concludes that the combination of the HSM model and language
with an ad hoc parallel base model proved successful in tackling the 
problems with clearer and more concise code than either of the alternative
languages.