Many-core acceleration of the first-principles all-electron quantum perturbation calculations

The first-principles quantum perturbation theory, also called density-functional perturbation theory (DFPT), is the state-of-the-art formalism to directly link the experimental response properties of the materials with the quantum modeling of the electrons. Here in this work, we present an implementation of all-electron DFPT for massively parallel Sunway many-core architectures to accelerate DFPT calculation. We have paid special attention to the calculation of the response density matrix, the real-space integration of the response density as well as the response Hamiltonian matrix. We also employ the fast and massively parallel linear scaling scheme together with the load balance algorithm for the DFPT calculations to improve the scalability. Using the above approaches, the accurate first-principles quantum perturbation calculations can be extended over millions of cores.