magritte, a modern software library for 3D radiative transfer – II. Adaptive ray-tracing, mesh construction, and reduction
magritte, a modern software library for 3D radiative transfer – II. Adaptive ray-tracing, mesh construction, and reduction
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Magritte，用于 3D 辐射传输的现代软件库 – II。
DOI：
10.1093/mnras/staa3199
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发表时间：
2020
影响因子：
4.8
通讯作者：
J. Hetherington
中科院分区：
文献类型：
--
作者：
F. De Ceuster;J. Bolte;W. Homan;S. Maes;J. Malfait;L. Decin;J. Yates;P. Boyle;J. Hetherington
辐射传输是一个众所周知的困难且计算量大的问题。然而，它是几乎所有天体物理和宇宙学模拟中不可或缺的成分。选择合适的离散化方案是仿真的关键部分，因为它不仅决定了模型的直接内存成本，而且在很大程度上决定了计算成本和可达到的精度。在本文中，我们展示了方向离散化方案和空间模型网格的适当选择如何有助于减轻计算成本，同时在很大程度上保持准确性。首先，我们讨论在 3D 辐射传输库 Magritte 中实现的自适应光线追踪方案，该方案使光线适应空间网格，并使用基于 Healpix 的分层方向离散化。其次，我们演示如何使用免费开源软件库 gmsh 生成可以轻松为 Magritte 定制的高质量网格。特别是，我们展示了如何使用网格的局部元素尺寸分布来优化分析和数值定义模型的采样。此外，我们表明，当使用流体动力学模拟的输出作为辐射传输模拟的输入时，输入模型中的元素数量通常可以减少一个数量级，而不会显着损失辐射场的精度。我们针对基于自适应网格细化产生的分层八叉树网格的两个模型以及基于平滑粒子流体动力学数据的两个模型演示了这一点。
Radiative transfer is a notoriously difficult and computationally demanding problem. Yet, it is an indispensable ingredient in nearly all astrophysical and cosmological simulations. Choosing an appropriate discretization scheme is a crucial part of the simulation, since it not only determines the direct memory cost of the model but also largely determines the computational cost and the achievable accuracy. In this paper, we show how an appropriate choice of directional discretization scheme as well as spatial model mesh can help alleviate the computational cost, while largely retaining the accuracy. First, we discuss the adaptive ray-tracing scheme implemented in our 3D radiative transfer library magritte, that adapts the rays to the spatial mesh and uses a hierarchical directional discretization based on healpix. Second, we demonstrate how the free and open-source software library gmsh can be used to generate high-quality meshes that can be easily tailored for magritte. In particular, we show how the local element size distribution of the mesh can be used to optimize the sampling of both analytically and numerically defined models. Furthermore, we show that when using the output of hydrodynamics simulations as input for a radiative transfer simulation, the number of elements in the input model can often be reduced by an order of magnitude, without significant loss of accuracy in the radiation field. We demonstrate this for two models based on a hierarchical octree mesh resulting from adaptive mesh refinement, as well as two models based on smoothed particle hydrodynamics data.
Magritte，一个用于 3D 辐射传输的现代软件库：I. 非 LTE 原子和分子线建模
影响因子：
4.8
作者：
De Ceuster F
通讯作者：
De Ceuster F