Materials and Molecular Modelling Exascale Design and Development Working Group

高性能计算机(HPC)或超级计算机通过原子学和电子结构建模，在理解、开发和越来越多地预测复杂材料的性质方面提供了令人兴奋的机会；随着硬件能力的增长，我们计算技术的范围和能力不断扩大。艾级系统的出现是这一演变的下一个戏剧性步骤。购买和运行这样一个系统的成本都很高，因此在用户使用艾斯卡设施之前，必须开发适当的软件。该项目的研究人员是国际领先的专家，致力于开发(使新科学成为可能)和优化(使模拟更高效)最先进的材料软件，用于在国内外的HPC上运行模拟。我们开发的软件在学术界和工业界都有使用。目前，我们的社区消耗了英国高性能计算设施(Archer)中约120,000个内核的三分之一以上(峰值性能为2.5x10^15 Flop/S)，我们预计不会有任何延误立即充分利用Archer的继任者，当它于今年晚些时候向英国学术界推出时，将由大约750,000个内核组成(估计为~28x10^15 Flop/S)。艾级计算机(根据定义&gt；10^18 flp/S)将由更多核心组成。然而，预计下一代国家计算机将不会提供从现有基础设施的平稳过渡，而是将经历英国国家设施的阶段性变化，从传统的基于CPU的体系结构转变为托管(多)多核加速器的CPU。在充分利用这些体系结构之前，我们的许多(如果不是全部)软件包将需要进行重大更改。软件的适当改动将减少核心之间的数据交换，管理CPU和加速器之间的通信，此外，还将适应我们处理输入和输出数据的程序。按照电话会议的要求，我们将通过汇集研究软件工程师(RSE)和来自数学和计算机科学的专家以及广泛的材料和分子建模(MMM)领域的专家，组成一个设计和开发工作组(DDWG)。我们代表着一个非常庞大和重要的共同体，这个共同体长期以来已经建立了发展、资源管理和传播最佳做法的机制，发展与发展工作组将加以利用。为了最大限度地发挥英国可用资金用于亿级计算的影响，我们确定了将使大多数社区受益的解决方案。我们的DDWG旨在将问题的基本数学与实现的计算机科学分开。我们将利用本领域和其他学科中的最佳当前实践和正在开发的实践，特别是以可被许多材料软件调用的库为目标，并提供通向异类体系结构的途径。作为补充，我们将处理新的工作流来管理和分析海量的模拟数据。我们将从我们与其他发展援助工作组的定期会议和会议以及与我们的国家和国际项目伙伴的知识转让中获得宝贵的经验。开展初步工作并确定需要什么(指定为下一个资助阶段的一部分)将丰富我们的专业知识，并促进与材料软件开发商和海外亿级计算机用户的国际合作。这项工作使英国MMM社区能够有效地利用亿级HPC资源来应对许多EPSRC重大挑战，包括功能材料的浮现和纳米级设计(物理学)；拨号分子和具有目标特性的扩展结构的定向组装(化学科学)；以及从原子到应用的工程(工程学)。

High Performance Computers (HPC), or supercomputers, offer exciting opportunities in understanding, developing and increasingly predicting the properties of complex materials through atomistic and electronic structure modelling; and the scope and power of our computational techniques continue to expand as the capability of the hardware grows. The advent of exascale systems is the next dramatic step in this evolution. There is a high cost of both purchasing and running such a system, so it is imperative that appropriate software is developed before users gain access to exascale facilities. The investigators of this project are internationally leading experts in developing (enabling new science) and optimising (making simulations more efficient) state-of-the-art materials software for running simulations on HPC, based here and abroad. Software that we have developed is used both in academia and in industry. Currently, our community consumes over a third of the UK's HPC facility (ARCHER) of approximately 120,000 cores (with a peak performance of 2.5x10^15 Flop/s) and we do not anticipate any delays in immediately getting the most out of the successor to ARCHER, which will be composed of approximately 750,000 cores (estimated at ~ 28x10^15 Flop/s) when it becomes available later this year to the UK academic community. Exascale computers (by definition >10^18 Flop/s) will be composed of many more cores. However, it is anticipated that the next generations of national computers will not provide a smooth transition from the existing infrastructures, but instead will undergo a step change for the UK national facilities, with a shift from conventional CPU based architectures to CPUs hosting (multiple) many-core accelerators. Many, if not all, of our software packages will require major changes before these architectures can be fully exploited. Appropriate changes to the software will effect a reduction in data exchange between cores, management of communications between CPU and accelerators, and, moreover, adaptation in our procedures for handling input and output data.As requested in the Call, we will form a design and development working group (DDWG) by bringing together Research Software Engineers (RSEs) and experts from mathematics and computer science with a wide range of domain experts in Materials and Molecular Modelling (MMM). We represent a very large and important community which has long established mechanisms for development, resource management, and disseminating best practices that the DDWG will exploit. To maximise the impact of the available UK funds for exascale computing, we identify solutions that will benefit most of our community.Our DDWG aims to separate out the fundamental mathematics of the problem from the computer science of implementation. We will exploit best current practices and those under development in our domain and across other disciplines in particular targeting libraries that can be called by many materials software and offer a route to heterogeneous architectures. In a complementary development, we will tackle new workflows to manage and analyse vast volumes of simulation data. We will gain valuable experience from our regular meetings and meetings with other DDWGs; and knowledge transfer with our national and international project partners. Undertaking of the initial work and identifying what is required (work earmarked as part of the next funding stage) will enrich our expertise and facilitate international collaborations with developers of materials software and users of overseas exascale computers.This work enables the UK MMM community to use exascale HPC resources efficiently to address many EPSRC Grand Challenges, including Emergence and Nanoscale Design of Functional Materials (Physics); Dial a Molecule and Directed Assembly of Extended Structures with Targeted Properties (Chemical Sciences); and Engineering From Atoms to Applications (Engineering).