Recent Advances in PARSEC for Performing Large-scale Electronic Structure Calculations in Real Space

The electronic structure of various types of materials, including complex biomolecules, nanostructures, and interfacial systems can be obtained by solving the Kohn–Sham (KS) equations. PARSEC, a real-space pseudopotential density functional theory KS equation solver, can routinely tackle systems with thousands of atoms using a Chebyshev-filtered subspace iteration (CheFSI) method. We will present a number of recent advances made in PARSEC that allow users to tackle larger systems that contain tens of thousands of atoms. These new advances include new parallelization strategies that significantly improve the scalability of orthogonalization and the Rayleigh–Ritz steps in the CheFSI framework and a more efficient way to perform the previously proposed spectrum slicing method. We will demonstrate the scalability of both the CheFSI and spectrum slicing methods on modern high performance computers and discuss the remaining challenges.