W. Joubert

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This paper compares the convergence behavior of two popular iterative methods for solving systems of linear equations: the s-step restarted minimal residual method (commonly implemented by algorithms such as GMRES(s)), and (s?1)-degree polynomial preconditioning. It is known that for normal matrices, and in particular for symmetric positive deenite(More)
Incomplete factorization preconditioners such as ILU, ILUT and MILU are well-known robust general-purpose techniques for solving linear systems on serial computers. However, they are difficult to parallelize efficiently. Various techniques have been used to parallelize these preconditioners, such as multicolor orderings and subdomain preconditioning. These(More)
This paper presents a fully parallel implementation of the global lexicographically ordered M/ILU preconditioning for linear systems arising from structured 3-D problems. M/ILU preconditionings, which are popular on conventional serial architectures, have not been easily amenable to parallelization due to their sequentiality, leading to the need to reorder(More)
In this paper we describe the Denovo code system. Denovo solves the six-dimensional, steady-state, linear Boltzmann transport equation, of central importance to nuclear technology applications such as reactor core analysis (neutronics), radiation shielding, nuclear forensics and radiation detection. The code features multiple spatial differencing schemes,(More)
—In this study we investigate computational workloads for the Jaguar system during its tenure as a 2.3 petaflop system at Oak Ridge National Laboratory. The study is based on a comprehensive analysis of MOAB and ALPS job logs over this period. We consider Jaguar utilization over time, usage patterns by science domain, most heavily used applications and(More)
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