Coupled-cluster Green's function (GFCC) calculation has drawn much attention in the recent years for targeting the molecular and material electronic structure problems from a many-body perspective in a systematically improvable way. However, GFCC calculations on scientific computing clusters usually suffer from expensive higher dimensional tensor contractions in the complex space, expensive inter-process communication, and severe load imbalance, which limits it's use for tackling electronic structure problems. Here we present a numerical library prototype that is specifically designed for large-scale GFCC calculations. The design of the library is focused on a systematically optimal computing strategy to improve its scalability and efficiency. The performance of the library is demonstrated by the relevant profiling analysis of running GFCC calculations on remote giant computing clusters. The capability of the library is highlighted by computing a wide near valence band of a fullerene C60 molecule for the first time at the GFCCSD level that shows excellent agreement with the experimental spectrum.

Program summary

Program Title: GFCCLib

CPC Library link to program files: https://doi.org/10.17632/j594wydctd.1

Code Ocean capsule: https://doi.org/10.24433/CO.5131827.v1

Licensing provisions: MIT License

Programming language: C++

Nature of problem: The applications of coupled cluster Green's function on large scale molecular electronic structure problems suffer from expensive higher dimensional tensor contractions in the complex space, expensive inter-process communication, and severe load imbalance. Tackling these issues are a key step in building high-performance coupled cluster Green's function library for its routine use in large scale molecular science.

Solution method: We have developed a C++ library for large scale molecular GFCC calculations on high-performance computing clusters. We provide implementations for high dimensional tensor algebra for many-body methods (TAMM), Cholesky decomposition of high dimensional electron repulsion integral tensors, process group technique for mitigating load imbalance. The library is written in C++. The source code, tutorials and documentation are provided online. A continuous integration mechanism is set up to automatically run a series of regression tests and check code coverage when the codebase is updated.

中文翻译：

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GFCCLib：可扩展且高效的耦合集群格林函数库，用于准确解决多体电子结构问题

近年来，耦合簇格林函数（GFCC）的计算已引起人们的广泛关注，它们以系统地改进的方式从多体角度解决了分子和材料的电子结构问题。但是，在科学计算集群上进行GFCC计算时，通常会遇到复杂空间中昂贵的高维张量收缩，昂贵的进程间通信以及严重的负载不平衡的情况，这限制了它在解决电子结构问题中的用途。这里我们提供一个数值库专为大规模GFCC计算而设计的原型。库的设计侧重于系统地优化计算策略，以提高其可伸缩性和效率。通过在远程巨型计算集群上运行GFCC计算的相关配置文件分析，可以证明该库的性能。该库的功能通过在GFCCSD水平上首次计算富勒烯C60分子的宽近价带来突出显示，与实验光谱显示出极好的一致性。

计划摘要

节目名称： GFCCLib

CPC库链接到程序文件： https : //doi.org/10.17632/j594wydctd.1

代码海洋舱： https : //doi.org/10.24433/CO.5131827.v1

许可条款： MIT许可

编程语言： C ++

问题的性质：耦合簇格林函数在大规模分子电子结构问题上的应用受到复杂空间中昂贵的高维张量收缩，昂贵的进程间通信以及严重的负载不平衡的困扰。解决这些问题是构建高性能耦合簇Green的函数库的关键步骤，该函数库可在大规模分子科学中常规使用。

解决方法：我们开发了一个C ++库，用于在高性能计算集群上进行大规模分子GFCC计算。我们提供了用于多体方法（TAMM）的高维张量代数，高维电子排斥积分张量的Cholesky分解，减轻负载不平衡的过程组技术的实现。该库是用C ++编写的。在线提供了源代码，教程和文档。设置了一种持续集成机制，以在代码库更新时自动运行一系列回归测试并检查代码覆盖率。