The statistical language R is favoured by many biostatisticians for processing microarray data. In recent times, the quantity of data that can be obtained in experiments has risen significantly, making previously fast analyses time consuming or even not possible at all with the existing software infrastructure. High performance computing (HPC) systems offer a solution to these problems but at the expense of increased complexity for the end user. The Simple Parallel R Interface is a library for R that aims to reduce the complexity of using HPC systems by providing biostatisticians with drop-in parallelised replacements of existing R functions. In this paper we describe parallel implementations of two popular techniques: exploratory clustering analyses using the random forest classifier and feature selection through identification of differentially expressed genes using the rank product method.

The statistical language R and its Bioconductor package are favoured by many biostatisticians for processing microarray data. The amount of data produced by some analyses has reached the limits of many common bioinformatics computing infrastructures. High Performance Computing systems offer a solution to this issue. The Simple Parallel R Interface (SPRINT) is a package that provides biostatisticians with easy access to High Performance Computing systems and allows the addition of parallelized functions to R. Previous work has established that the SPRINT implementation of an R permutation testing function has close to optimal scaling on up to 512 processors on a supercomputer. Access to supercomputers, however, is not always possible, and so the work presented here compares the performance of the SPRINT implementation on a supercomputer with benchmarks on a range of platforms including cloud resources and a common desktop machine with multiprocessing capabilities. Copyright © 2011 John Wiley & Sons, Ltd.

BACKGROUND: Microarray analysis allows the simultaneous measurement of thousands to millions of genes or sequences across tens to thousands of different samples. The analysis of the resulting data tests the limits of existing bioinformatics computing infrastructure. A solution to this issue is to use High Performance Computing (HPC) systems, which contain many processors and more memory than desktop computer systems. Many biostatisticians use R to process the data gleaned from microarray analysis and there is even a dedicated group of packages, Bioconductor, for this purpose. However, to exploit HPC systems, R must be able to utilise the multiple processors available on these systems. There are existing modules that enable R to use multiple processors, but these are either difficult to use for the HPC novice or cannot be used to solve certain classes of problems. A method of exploiting HPC systems, using R, but without recourse to mastering parallel programming paradigms is therefore necessary to analyse genomic data to its fullest. RESULTS: We have designed and built a prototype framework that allows the addition of parallelised functions to R to enable the easy exploitation of HPC systems. The Simple Parallel R INTerface (SPRINT) is a wrapper around such parallelised functions. Their use requires very little modification to existing sequential R scripts and no expertise in parallel computing. As an example we created a function that carries out the computation of a pairwise calculated correlation matrix. This performs well with SPRINT. When executed using SPRINT on an HPC resource of eight processors this computation reduces by more than three times the time R takes to complete it on one processor. CONCLUSION: SPRINT allows the biostatistician to concentrate on the research problems rather than the computation, while still allowing exploitation of HPC systems. It is easy to use and with further development will become more useful as more functions are added to the framework.

Grid application performance is inherently dependent on the performance and reliability of the underlying network. In a production Grid infrastructure, network performance monitoring (NPM) information is required both for middleware resource-brokering decisions and operational monitoring. A variety of NPM frameworks are available which can provide such information. However, the diverse global nature of the EGEE (Enabling Grids for E-sciencE) fabric means it is impractical to mandate a single monitoring solution. In this paper we propose a broker-based federated architecture for integration of NPM information from a heterogeneous set of monitoring frameworks, which provides simplified access to the frameworks for clients. We also present an overview of the requirements for NPM gathered from EGEE middleware developers and operational monitoring users. Finally, we describe our pilot implementation which has proven the validity of the architecture and demonstrated the first integrated access to backbone and end-to-end data gathered using different monitoring frameworks.

Production Grid infrastructure requires end-to- end guarantees on the Quality of Service from the underlying networks. In this paper, we present use cases for advance network resource reservation and then describe a multi-layered architecture that can support them. The architecture presents a single bandwidth broker, called BAR, which sits at the Grid layer. BAR not only provides a single point of access to Grid applications to reserve guaranteed end-to-end bandwidth, but also presents its interface in application terms (instead of networking terms). We expose two guaranteed bandwidth services: the Guaranteed Delivery File Transfer and Virtual Leased Line services. Integrated with the GEANT2 bandwidth on demand infrastructure, our bandwidth broker deals with multiple network domains, further insulating the applications from network concerns. We also define additional components required for an end-to-end reservation as well as the interfaces between the components. Our deployed prototype demonstrated the world's first software-based, inter-domain bandwidth reservations based on Premium IP.

This paper describes the DESHL -- an open standards-based means for accessing the DEISA consortium's heterogeneous supercomputing Grid. The paper provides some background on DEISA before giving an overview of the functionality and architecture of the DESHL.

A number of scientific models are discussed that possess a high degree of inherent parallelism. For simulation purposes this is exploited by employing a massively parallel SIMD (single instruction multiple data) computer. The authors describe one such computer, the distributed array processor (DAP), and discuss the optimal mapping of a typical problem onto the computer architecture to best exploit the model parallelism. By focusing on specific models currently under study, they exemplify the types of problems which benefit most from a parallel implementation. The extent of this benefit is considered relative to implementation on a machine of conventional architecture.>