D1.1 First report on MAX software architecture and implementation planning

This report describes the main developments that will be performed on the M A X codes –B IG DFT, FLEUR, Q UANTUM ESPRESSO, SIESTA, and YAMBO– to extend their portability, improve their efficiency and scalability, streamline their deployment and main- tenance, enable selected new features and a common M A X interoperability layer. The final objective of this work is to make the codes able to operate at full efficiency on pre-exascale and exascale machines and to pave the way for the realisation of the M A X Lighthouse applications that will be deployed on the EuroHPC clusters. We have struc- tured the four year work-plan into three main stages: • The initial phase will address all preliminary work needed to ensure the availability of stable and efficient production versions of the codes and develop a software engineering framework to streamline the development activities. We will reach these objectives with the M12 release. We will realise proofs-of-concept, testing, and early deployment solutions for specific machines and architectures. The output of this work will serve as a base for preparing the D1.3 deliverable at M18, which will update this Software Development Plan and conclude the initial phase. • In the second stage, we will implement the core part of our plan, which, at least as test/beta features, will be part of the M30 release, representing the second mile- stone of our work plan. • In the final stage, we will work on the finalisation of our plan, improving code robustness and resilience, and inserting the improvements and technical solutions indicated by the other work packages: WP2 for what concerns the Lighthouse applications and the interoperability, and WP3 and WP4 for fine-tuning and op- timisation of our codes and libraries in the different platforms of interest. These outcomes and the Lighthouse application apparel will be delivered with the M48 release. [...]