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Convolutive decomposition and fast summation methods for discrete-velocity approximations of the Boltzmann equation
Clément Mouhot 1, Lorenzo Pareschi 2, Thomas Rey 3
(18/01/2012)

Discrete-velocity approximations represent a popular way for computing the Boltzmann collision operator. The direct numerical evaluation of such methods involve a prohibitive cost, typically $O(N^{2d+1})$ where $d$ is the dimension of the velocity space. In this paper, following the ideas introduced in [26,27], we derive fast summation techniques for the evaluation of discrete-velocity schemes which permits to reduce the computational cost from $O(N^{2d+1})$ to $O(\bar{N}^d N^d\log_2 N)$, $\bar{N} << N$, with almost no loss of accuracy.
1 :  DPMMS/CMS
University of Cambridge
2 :  Department of Mathematics (DPT OF MATH., UNIV. OF FERRARA)
Università degli studi di Ferrara
3 :  Institut Camille Jordan (ICJ)
CNRS : UMR5208 – Université Claude Bernard - Lyon I – Ecole Centrale de Lyon – Institut National des Sciences Appliquées (INSA) - Lyon
Mathématiques/Analyse numérique

Mathématiques/Equations aux dérivées partielles
Boltzmann equation – Discrete-velocity approximations – Discrete-Velocity Methods – Fast summation methods – Farey series – Convolutive decomposition
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