用于无碰撞N体模拟的分层哈密顿分裂积分器的评价
Assessing the Hierarchical Hamiltonian Splitting Integrator for Collisionless N-body Simulations
摘要：
在一些天体物理学N体问题中，大的动态范围导致使用自适应多时间步长;然而，寻找最佳策略仍然具有挑战性。我们数值量化的性能的分层哈密顿分裂（HHS）积分器的碰撞模拟使用直接求和代码。我们比较HHS与恒定全局时间步长蛙跳积分器，并与自适应（AKDK）。我们发现HHS是近似可逆的，而AKDK不是。因此，可以找到HHS的能量漂移相当温和的参数组合，从而获得更好的性能。我们的结论是，HHS是一个有吸引力的替代AKDK，它肯定是有利的直接求和和P3 M码。此外，我们发现GADGET 4（树/FMM）HHS实施的优势，值得进一步探索。
英文摘要：
The large dynamic range in some astrophysical N-body problems led to the use of adaptive multi-time-steps; however, the search for optimal strategies is still challenging. We numerically quantify the performance of the hierarchical Hamiltonian Splitting (HHS) integrator for collisionless simulations using a direct summation code. We compare HHS with the constant global time-step leapfrog integrator, and with the adaptive one (AKDK). We find that HHS is approximately reversible, whereas AKDK not. Therefore, it is possible to find a combination of parameters where the energy drift is considerably milder for HHS, resulting in a better performance. We conclude that HHS is an attractive alternative to AKDK, and it is certainly advantageous for direct summation and P3M codes. Also, we find advantages with GADGET4 (Tree/FMM) HHS implementation that are worth exploring further.
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