Towards fast and accurate exascale density functional theory calculations using DFT-FE -- a massively parallel real-space code using adaptive finite-element discretization

Kohn-Sham density functional theory (DFT) calculations have been instrumental in providing many crucial insights into materials behavior and occupy a sizable fraction of world’s computational resources today. However, the stringent accuracy requirements in DFT needed to compute meaningful material properties, in conjunction with the asymptotic cubic-scaling computational complexity with number of electrons, demand huge computational resources. Thus, these calculations are routinely limited to material systems with at most few thousands of electrons. In this talk, we present a significant advance in the state-of-the-art for accurate DFT calculations -via- the development of DFT-FE, that has enabled fast, scalable and accurate large-scale DFT calculations on material systems with tens of thousands of electrons. This has been facilitated by (i) the development of efficient and accurate spatially adaptive discretization strategies using higher-order finite-element discretization; (ii) developing efficient and scalable algorithms in conjunction with mixed-precision strategies; (iii) implementation innovations, both on many core and hybrid architectures, that significantly improve performance.