Methods for Large Scale Density Functional Calculations

There are two scalability bottlenecks in conventional density functional calculations. One is the calculation of the Kohn-Sham matrix elements (mostly the electrostatic part), the other the update of the wavefunctions in the self-consistency cycle (diagonalization). Both parts scale nominally with the third power of the system size. It has been shown that all parts of the calculation can be made linearly scaling by making use of locality principles. We have developed the Gaussian and Augmented-Plane Wave (GAPW) method that serves as a basic tool to achieve overall linear scaling in accurate density functional calculations. Current projects focus on the implementation of new algorithms to improve the performance of the Kohn-Sham matrix build up and on stable and general algorithms for fast wavefunction update methods. In addition methods for frozen density descriptions of molecular liquids are developed.

All developments are incorporated into the CP2K computer code (cp2k.berlios.de).