Development of Cello/Enzo-P: An Extremely Scalable Adaptive Mesh Refinement Framework and Code for Astrophysics and Cosmology

该奖项支持Cello的开发，Cello是一种新的并行自适应网格细化（AMR）软件框架。Cello的目的是使研究人员能够编写多物理AMR应用程序，这些应用程序可以利用当前和未来世界级高性能计算（HPC）平台的巨大计算能力。相对于现有AMR框架的显著特征是在软件数据结构和硬件并行性方面对极端可扩展性的积极追求。开发Cello不可或缺的一部分是开发Enzo-P，这是一个基于Cello框架构建的千万亿次天体物理学和宇宙学应用程序。Enzo-P不仅有助于推动底层Cello框架的开发，而且它将作为Enzo terascale天体物理学和宇宙学社区代码的高度可扩展变体。Enzo-P科学应用程序和底层独立的Cello并行AMR软件框架将作为社区软件发布和支持。软件可持续性将在加州圣地亚哥大学计算天体物理实验室（LCA）和圣地亚哥超级计算机中心的双重支持下实现。致力于社区科学代码和HPC网络基础设施的长期维护和用户支持的组织。软件自我管理将是Cello软件设计的一个组成部分，软件弹性是一个高度优先事项。Cello框架将被设计为检测硬件和软件故障，识别性能和数值问题，并动态重新配置，以始终在当前可用的硬件组件上以最高的效率执行。能量效率可以被认为隐含在底层自适应网格细化方法中，该方法动态地将计算资源定位在需要的地方，并避免在不需要的地方消耗资源。AMR的适应性直接转化为节能。该项目综合了现有并行AMR框架的最佳实践，并增加了几项创新，提高了各种类型模拟的网格质量。并行和负载平衡的分层方法，同时执行本地性的最大限度，而放宽全球同步到最低限度。这将使AMR应用程序的前所未有的空间和时间动态范围的建设明天的分层HPC架构。 自适应网格加密已被证明是一个强大的数值技术，在各种学科的纯和应用科学和工程。现有的框架可能无法扩展到数千万或数亿个核心，这意味着构建在它们之上的现有应用程序将需要迁移到更具可扩展性和容错性的框架。Cello是在考虑这些应用程序的情况下构建的。这种软件开发的更广泛影响将来自Cello支持的科学和工程应用，以及它所体现的新颖设计原则。

This award supports the development of Cello, a new parallel adaptive mesh refinement (AMR) software framework. The purpose of Cello is to enable researchers to write multi-physics AMR applications that can harness the enormous computing power of current and future world-class high- performance computing (HPC) platforms. The distinguishing characteristic relative to existing AMR frameworks is the aggressive pursuit at the onset of extreme scalability, both in terms of software data structures and hardware parallelism. Integral to developing Cello will be developing Enzo-P, a petascale astrophysics and cosmology application built on top of the Cello framework. Enzo-P will not only help drive development of the underlying Cello framework, but it will serve as a highly scalable variant of the Enzo terascale astrophysics and cosmology community code. Both the Enzo-P science application, and the underlying independent Cello parallel AMR software framework, will be released and supported as community software.Software sustainability will be realized under the dual support of the Laboratory for Computational Astrophysics (LCA) at the University of California San Diego, and the San Diego Supercomputer Center, organizations devoted to the long-term maintenance of---and user support for---community scientific codes and HPC cyberinfrastructure. Software self-management will be an integral component of the Cello software design, with software resilience a high priority. The Cello framework will be designed to detect hardware and software faults, identify performance and numerical issues, and dynamically reconfigure to always perform with the highest possible efficiency on currently available hardware components. Energy efficiency can be considered implicit in the underlying adaptive mesh refinement approach, which dynamically targets computational resources where they are required, and avoids expending resources where they are not. The adaptivity of AMR translates directly to energy savings. This project synthesizes the best practices of existing parallel AMR frameworks and adds several innovations that improve the quality of the mesh for various types of simulations. A hierarchical approach to parallelism and load balancing is taken while enforcing locality to the maximum while relaxing global synchronization to a minimum. This will enable the construction of AMR applications of unprecedented spatial and temporal dynamic range on tomorrow's hierarchical HPC architectures. Adaptive mesh refinement has proven to be a powerful numerical technique in a wide variety of disciplines in the pure and applied sciences and engineering. Existing frameworks will probably not be scalable to tens and hundreds of millions of cores, meaning that existing applications built on them will need to move to more scalable and fault tolerant frameworks. Cello is being built with these applications in mind. The broader impacts of this software development will come through the science and engineering applications that Cello supports, as well as novel design principles it embodies.