Volume 10 Issue 4 March 2012


After 10 Years: Back to Where We Began



C. C. Chancey


University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

A New Vectorization Technique for Expression Templates in C++


Authors and Affiliations:

J. Progsch and Y. Ineichen
Department of Computational Science, ETH-Zürich, CAB H 83.2, Universitätstrasse 6, 8092 Zürich SWITZERLAND

A. Adelmann
Paul Scherrer Institute, 5232 Villigen PSI, SWITZERLAND


Vector operations play an important role in high performance computing and are typically provided by highly optimized libraries that implement the Basic Linear Algebra Subprograms (BLAS) interface. In C++ templates and operator overloading allow the implementation of these vector operations as expression templates which construct custom loops at compile time and providing a more abstract interface. Unfortunately existing expression template libraries lack the performance of fast BLAS implementations. This paper presents a new approach – Statically Accelerated Loop Templates (SALT) – to close this performance gap by combining expression templates with an aggressive loop unrolling technique. Benchmarks were conducted using the Intel C++ compiler and GNU Compiler Collection to assess the performance of our library relative to Intel’s Math Kernel Library as well as the Eigen template library. The results show that the approach is able to provide optimization comparable to the fastest available BLAS implementations, while retaining the convenience and flexibility of a template library.

Determining the Efficacy of IonatorEXP™ Activated Tap Water on Growth of Staphyloccocus aures and Escherichia coli.



Sara Schiedler, Rachelle Peterson, and Sasha Showsh (Department of Biology)

Thao Yang (Department of Chemistry)


University of Wisconsin, PO Box 4004, Eau Claire, Wisconsin 54702 USA


The efficacy in growth inhibition of Staphylococcus aureus and Escherichia coli of the IonatorEXP™ activated tap water was compared to plain tap water, Quatsyl™, and Butchers Neutral Disinfectant™. Treatment with Quatsyl™ or Butchers Morning Mist™ Neutral Disinfectant resulted in complete inhibition of growth for both S. aureus and E.coli. Treatments with IonatorEXP™ activated tap water, performed as directed by the manufacturer, or plain tap water, resulted in no observable inhibition of growth for either of the bacterial strains tested. This observation is not unexpected given that analysis of pH, conductivity and H2O2 on IonatorEXP™ activated tap water were statistically the same values as those determined for plain tap water that was not activated by the IonatorEXP™.

A Multi-Objective, Linked-Simulation-Optimization of Henry’s Saltwater Intrusion Problem using HST3D and Box’s Method



Emily Curtis and Robert Willis


Department of Environmental Resources Engineering, Humboldt State University, Arcata, California 95521 USA


A multi-objective linked simulation and optimization (LSO) model for a three dimensional saltwater intrusion problem has been developed. The LSO employs HST3D and Box’s algorithm. The weighting method of multi-objective optimization solves the multi-objective planning problem. The model is capable of determining the optimal pumping rates that minimize the saline concentration at the well sites, as well as, the cost associated with pumping, while satisfying an exogenous water demand. The model is valid for a wide range of applications as explicitly defined by the simulation model. The application of the model was limited to a modified version of Henry’s saltwater intrusion problem. Henry’s problem was modified to include a third spatial dimension and well sites. The multi-objective optimization yielded explicit tradeoff information between the two objectives.