ColDICE: A parallel Vlasov-Poisson solver using moving adaptive simplicial tessellation

JOURNAL OF COMPUTATIONAL PHYSICS

卷:321

Article

Sousbie, Thierry^1,2,3,4  Colombi, Stephane^1,2,5 

[1] CNRS, Inst Astrophys Paris, UMR 7095, 98bis, F-75014 Paris, France

[2] UPMC, 98bis, F-75014 Paris, France

[3] Univ Tokyo, Dept Phys, Tokyo 1130033, Japan

[4] Univ Tokyo, Sch Sci, Res Ctr Early Universe, Tokyo 1130033, Japan

[5] Kyoto Univ, Yukawa Inst Theoret Phys, Kyoto 6068502, Japan

关键词: Vlasov-Poisson;    Tessellation;    Simplicial mesh;    Refinement;    Dark matter;    Cosmology;   

DOI  :  10.1016/j.jcp.2016.05.048

来源: Elsevier

【 摘 要 】

Resolving numerically Vlasov-Poisson equations for initially cold systems can be reduced to following the evolution of a three-dimensional sheet evolving in six-dimensional phase-space. We describe a public parallel numerical algorithm consisting in representing the phase-space sheet with a conforming, self-adaptive simplicial tessellation of which the vertices follow the Lagrangian equations of motion. The algorithm is implemented both in six-and four-dimensional phase-space. Refinement of the tessellation mesh is performed using the bisection method and a local representation of the phase-space sheet at second order relying on additional tracers created when needed at runtime. In order to preserve in the best way the Hamiltonian nature of the system, refinement is anisotropic and constrained by measurements of local Poincare invariants. Resolution of Poisson equation is performed using the fast Fourier method on a regular rectangular grid, similarly to particle in cells codes. To compute the density projected onto this grid, the intersection of the tessellation and the grid is calculated using the method of Franklin and Kankanhalli [65-67] generalised to linear order. As preliminary tests of the code, we study in four dimensional phase-space the evolution of an initially small patch in a chaotic potential and the cosmological collapse of a fluctuation composed of two sinusoidal waves. We also perform a warm dark matter simulation in six-dimensional phase-space that we use to check the parallel scaling of the code. (C) 2016 Elsevier Inc. All rights reserved.

【 授权许可】

Free