MPI parallelization of the first-principles pseudopotential method program with respect to each band

We have developed an efficient parallelized program for large-scale calculations in the framework of the first-principles pseudopotential method. This program uses the residual minimization method-direct inversion in the iterative subspace method which was originally proposed by Pulay and recently implemented by Kresse and Furthmuller, to efficiently obtain the electronic ground state. This method is more suitable for parallel computations with respect to each band than other algorithms such as Car-Parrinello or conjugate-gradient schemes. We have tested the message passing interface (MPI)-parallel computations of the program applied to relatively large systems using two kinds of parallel computer, the multinode supercomputer and the personal computer cluster. We have found that the developed program can attain a very high efficiency of parallelization for the two kinds of computers.