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Computational Physics - Findings from University of Regensburg provide new insights into computational physics

2010 AUG 19 - (VerticalNews.com) -- "The overlap operator in lattice QCD requires the computation of the sign function of a matrix, which is non-Hermitian in the presence of a quark chemical potential. In previous work we introduced an Arnoldi-based Krylov subspace approximation, which uses long recurrences," scientists writing in the journal Computer Physics Communications report.

"Even after the deflation of critical eigenvalues, the low efficiency of the method restricts its application to small lattices. Here we propose new short-recurrence methods which strongly enhance the efficiency of the computational method. Using rational approximations to the sign function we introduce two variants, based on the restarted Arnoldi process and on the two-sided Lanczos method, respectively, which become very efficient when combined with multishift solvers. Alternatively, in the variant based on the two-sided Lanczos method the sign function can be evaluated directly. We present numerical results which compare the efficiencies of a restarted Arnoldi-based method and the direct two-sided Lanczos approximation for various lattice sizes," wrote J.C.R. Bloch and colleagues, University of Regensburg ...read more

Computational Physics - Research data from T. Giorgino and colleagues update understanding of computational physics

2010 AUG 19 - (VerticalNews.com) -- According to recent research from Barcelona, Spain, "Distributed computing (DC) projects tackle large computational problems by exploiting the donated processing power of thousands of volunteered computers, connected through the Internet. To efficiently employ the computational resources of one of world's largest DC efforts, GPUGRID, the project scientists require tools that handle hundreds of thousands of tasks which run asynchronously and generate gigabytes of data every day. ...read more

Computational Physics - Data on computational physics described by R.B. Frigori et al

2010 AUG 19 - (VerticalNews.com) -- According to recent research published in the journal Computer Physics Communications, "Short-time dynamics technique is used to study the relaxation process for the (2 + 1)-dimensional critical gluodynamics of the SU(2) lattice-gauge theory."

"A generalized class of heat-bath-inspired updating algorithms was employed during the short-time regime of the dynamic evolution for performance comparison. The static and dynamic critical exponents of the theory were measured, serving as a dynamic benchmark for algorithmic efficiency," wrote R.B. Frigori and colleagues ...read more

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