An Integrated Science Environment for Astrophysical Simulations

天体物理模拟代码以及天体物理数据变得越来越复杂：模拟现在能够探测恒星、星系、黑洞和许多其他不同现象的形成。然而，随着模拟变得越来越大，管理这些模拟的物理模型变得越来越复杂，开发模拟代码和分析这些模拟输出的数据的固有困难也相应增加。许多不同的、经常相互竞争的小组使用独立的模拟平台，这使得由于技术不兼容而无法进行实质性的协作。为了缓解这种碎片化，这项研究涉及为天体物理计算和可视化创建一个综合科学环境。这种综合科学环境被设计成同样适用于新用户以及在NSF资助的Blue Waters等平台上进行的千万亿级模拟。这项研究产生的综合科学环境由三个主要组件组成：模拟平台界面、初始条件生成器以及分析和可视化引擎。仿真平台接口将各个仿真平台的内部数据结构和单元处理抽象为与物理相关的量，提供兼容层，使微物理解算器(如化学、辐射冷却和流体力学)能够原封不动地应用于多个平台。初始条件生成器创建天体物理模拟的起点，从而实现直观的初始条件生成和结果的直接跨代码比较和验证。最后，分析引擎产生高质量的定量结果和可视化，包括天文馆质量的可视化工具。集成科学环境是完全MPI并行化的，主要是用Python语言编写的，带有用于在模拟过程中进行现场或并发分析和可视化的API，可扩展到数十万个处理器。

Astrophysical simulation codes, as well as astrophysical data, have grown increasingly complex: simulations are now able to probe the formation of stars, galaxies, black holes and many other disparate phenomena. However, as simulations become larger, and the physical models governing those simulations become more complex, the inherent difficulties in developing simulation codes and analyzing the data output from these simulations grow commensurately. Many different, often competing, groups utilize independent simulation platforms, which prevents substantial collaboration as a result of technical incompatibilities. To mitigate this fragmentation, this research involves the creation of an Integrated Science Environment for both astrophysical computation and visualization. This Integrated Science Environment is designed to work equally well for new users as well as for petascale simulations on platforms such as the NSF-funded Blue Waters. The Integrated Science Environment produced by this research is constructed out of three primary components: a simulation platform interface, an initial conditions generator, and an analysis and visualization engine. The simulation platform interface abstracts the internal data structures and unit-handling of individual simulation platforms into physically-relevant quantities, providing a compatibility layer enabling microphysical solvers (such as chemistry, radiative cooling, and hydrodynamics) to be applied to multiple platforms unmodified. The initial conditions generator creates the starting points for astrophysical simulations, enabling both intuitive initial conditions generation and straightforward cross-code comparison and validation of results. Finally, the analysis engine produces high-quality quantitative results and visualizations, including planetarium-quality visualization tools. The Integrated Science Environment is fully MPI-parallelized and is written primarily in Python with APIs for in situ or concurrent analysis and visualization to be conducted during the course of a simulation, scaling up to hundreds of thousands of processors.