Software design of ACES III with the super instruction architecture

The Advanced Concepts in Electronic Structure (ACES) III software is a completely rewritten implementation for parallel computer architectures of the most used capabilities in ACES II, including the calculation of the electronic structure of molecular ground states and excited states, and determination of molecular geometries and of vibrational frequencies using many‐body and coupled cluster methods. To achieve good performance on modern parallel systems while simultaneously offering a software development environment that allows rapid implementation of new methods and algorithms, ACES III was written using a new software infrastructure, the super instruction architecture comprising a domain‐specific language, super instruction assembly language (SIAL), and a sophisticated runtime environment, super instruction processor (SIP). The architecture of ACES III is described as well as the inner workings of SIAL and SIP. The execution performance of ACES III and the productivity of programming in SIAL are discussed.