New developments in SIESTA for high-performance materials simulations

For over two-decades, SIESTA has enabled the treatment of large systems with first-principles electronic-structure methods, bringing new opportunities to many disciplines. At the core of SIESTA's efficiency is the use of a basis of strictly-localized atomic orbitals. The reduced cardinality of the basis and the sparsity of the Hamiltonian means that systems composed of dozens to hundreds of atoms can be treated with modest hardware, and that the programme can employ novel algorithms to extend its applicability to even larger systems. Within the MaX project, which is preparing materials-simulation codes for the upcoming extreme-scale HPC systems, this baseline efficiency has been extended, alongside the domain of applicability of SIESTA with the addition of new features. These extensions will be the focus of this webinar. A very important aspect of these improvements to the usability and performance of the programme is that they are an example of the power of modularization and code reuse, which have been espoused by MaX and by other international initiatives, such as the Electronic Structure Library and the ELSI project. This webinar will cover in particular the new developments in the area of electronic structure solvers, notably the incorporation of an interface to the ELSI library, which has enabled significant performance enhancements, including GPU acceleration. Another representative area of SIESTA's use domain is ballistic electronic transport. In the webinar we will present an overview of the TranSIESTA built-in module, which implements a formalism based on non-equilibrium Green's functions, and the latest improvements in its functionality (in particular multi-electrode support) and optimisation. The webinar will also highlight the efforts being made in enhancing user support within the SIESTA ecosystem, an area of great relevance in view of the extra complexity that emerges when considering the variety of novel architectures and features.