We describe the object-oriented implementation of a higher-order
finite-difference density-functional code in Fortran 90. Object-oriented models
of grid and related objects are constructed and employed for the implementation
of an efficient one-way multigrid method we have recently proposed for the
density-functional electronic-structure calculations. Detailed analysis of
performance and strategy of the one-way multigrid scheme will be presented.Comment: 24 pages, 6 figures, to appear in Comput. Phys. Com
