Titanium is an explicitly parallel dialect of JavaTM designed for high-performance scientific programming. We present an overview of the language features and demonstrate their use in the context of the NAS Parallel Benchmarks, a standard suite of common scientific kernels. We argue that parallel languages like Titanium provide greater expressive power than conventional approaches, enabling much more concise and expressive code that minimizes time to solution. Moreover, we have found that the Titanium implementations of three of the NAS Parallel Benchmarks can match or even exceed the performance of the standard Fortran/MPI implementations at realistic problem sizes and processor scales, while still using far cleaner, shorter and more maintainable code. © 2006 Springer-Verlag Berlin Heidelberg.

A fundamental problem in the analysis of parallel programs is to determine when two statements in a program may run concurrently. This analysis is the parallel analog to control flow analysis on serial programs and is useful in detecting parallel programming errors and as a precursor to semantics-preserving code transformations. We consider the problem of analyzing parallel programs that access shared memory and use barrier synchronization, specifically those with textually aligned barriers and single-valued expressions. We present an intermediate graph representation for parallel programs and an efficient interprocedural analysis algorithm that conservatively computes the set of all concurrent statements. We improve the precision of this algorithm by using context-free language reachability to ignore infeasible program paths. We then apply the algorithms to static race detection and show that it can benefit from the concurrency information provided. © 2006 Springer-Verlag Berlin Heidelberg.

Specialized computational chemistry packages have permanently reshaped the landscape of chemical and materials science by providing tools to support and guide experimental efforts and for the prediction of atomistic and electronic properties. In this regard, electronic structure packages have played a special role by using first-principle-driven methodologies to model complex chemical and materials processes. Over the past few decades, the rapid development of computing technologies and the tremendous increase in computational power have offered a unique chance to study complex transformations using sophisticated and predictive many-body techniques that describe correlated behavior of electrons in molecular and condensed phase systems at different levels of theory. In enabling these simulations, novel parallel algorithms have been able to take advantage of computational resources to address the polynomial scaling of electronic structure methods. In this paper, we briefly review the NWChem computational chemistry suite, including its history, design principles, parallel tools, current capabilities, outreach, and outlook.