The advantages of pattern-based programming have been well-documented in the sequential programming literature. However patterns have yet to make their way into mainstream parallel computing, even though several research tools support them. There are two critical shortcomings of pattern (or template) based systems for parallel programming: lack of extensibility and performance. This paper describes our approach for addressing these problems in the CO/sub 2/P/sub 3/S parallel programming system. CO/sub 2/P/sub 3/S supports multiple levels of abstraction, allowing the user to design an application with high-level patterns, but move to lower levels of abstraction for performance tuning. Patterns are implemented as parameterized templates, allowing the user the ability to customize the pattern to meet their needs. CO/sub 2/P/sub 3/S generates code that is specific to the pattern/parameter combination selected by the user. The MetaCO/sub 2/P/sub 3/S tool addresses extensibility by giving users the ability to design and add new pattern templates to CO/sub 2/P/sub 3/S. Since the pattern templates are stored in a system-independent format, they are suitable for storing in a repository to be shared throughout the user community.

A design pattern encapsulates the knowledge of object-oriented designers into re-usable artifacts. A design pattern is a descriptive device that fosters software design re-use. There are several reasons why design patterns are not used as generative constructs that support code re-use. The first reason is that design patterns describe a set of solutions to a family of related design problems and it is difficult to generate a single body of code that adequately solves each problem in the family. A second reason is that it is difficult to construct and edit generative design patterns. A third major impediment is the lack of a tool-independent representation. A common representation could lead to a shared repository to make more patterns available. We describe a new approach to generative design patterns that solves these three difficult problems. We illustrate this approach using tools called CO/sub 2/P/sub 2/S and Meta-CO/sub 2/P/sub 2/S but our approach is tool-independent.