Exceptions for Algorithmic Skeletons

Algorithmic skeletons offer high-level abstractions for parallel programming based on recurrent parallelism patterns. Patterns can be combined and nested into more complex parallelism behaviors. Programmers fill the skeleton patterns with the functional (business) code, which transforms the generic skeleton into a specific application. However, when the functional code generates exceptions, programmers are exposed to implementation details of the skeleton library, breaking the high-level abstraction principle. Furthermore, related parallel activities must be stopped as the exception is raised. This paper describes how to handle exceptions in algorithmic skeletons without breaking the highlevel abstractions of the programming model. We describe both the behavior of the framework in a formal way, and its implementation in Java: the Skandium Library.