Two Fundamental Concepts in Skeletal Parallel Programming

We define the concepts of nesting mode and interaction mode as they arise in the description of skeletal parallel programming systems. We sugegs

A parallel pattern for iterative stencil + reduce

We advocate the Loop-of-stencil-reduce pattern as a means of simplifying the implementation of data-parallel programs on heterogeneous multi-core platforms. Loop-of-stencil-reduce is general enough to subsume map, reduce, map-reduce, stencil, stencil-reduce, and, crucially, their usage in a loop in both data-parallel and streaming applications, or a combination of both. The pattern makes it possible to deploy a single stencil computation kernel on different GPUs. We discuss the implementation of Loop-of-stencil-reduce in FastFlow, a framework for the implementation of applications based on the parallel patterns. Experiments are presented to illustrate the use of Loop-of-stencil-reduce in developing data-parallel kernels running on heterogeneous systems

Archiving and referencing source code with Software Heritage

Software, and software source code in particular, is widely used in modern research. It must be properly archived, referenced, described and cited in order to build a stable and long lasting corpus of scientic knowledge. In this article we show how the Software Heritage universal source code archive provides a means to fully address the first two concerns, by archiving seamlessly all publicly available software source code, and by providing intrinsic persistent identifiers that allow to reference it at various granularities in a way that is at the same time convenient and effective. We call upon the research community to adopt widely this approach.Comment: arXiv admin note: substantial text overlap with arXiv:1909.1076

Optimizing Feature Interaction Detection

© 2017, Springer International Publishing AG. The feature interaction problem has been recognized as a general problem of software engineering. The problem appears when a combination of features interacts generating a conflict, exhibiting a behaviour that is unexpected for the features considered in isolation, possibly resulting in some critical safety violation. Verification of absence of critical feature interactions has been the subject of several studies. In this paper, we focus on functional interactions and we address the problem of the 3-way feature interactions, i.e. interactions that occur only when three features are all included in the system, but not when only two of them are. In this setting, we define a widely applicable definition framework, within which we show that a 3 (or greater)-way interaction is always caused by a 2-way interaction, i.e. that pairwise sampling is complete, hence reducing to quadratic the complexity of automatic detection of incorrect interaction

Exceptions for Algorithmic Skeletons

to appearInternational audienceAlgorithmic 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 generate exceptions, this exposes the programmer to 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 high-level 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