title: A Sparse Self-Consistent Field Algorithm and Its Parallel Implementation: Application to Density-Functional-Based Tight Binding.
abstract: We present an algorithm and its parallel implementation for solving a self-consistent problem as encountered in Hartree-Fock or density functional theory. The algorithm takes advantage of the sparsity of matrices through the use of local molecular orbitals. The implementation allows one to exploit efficiently modern symmetric multiprocessing (SMP) computer architectures. As a first application, the algorithm is used within the density-functional-based tight binding method, for which most of the computational time is spent in the linear algebra routines (diagonalization of the Fock/Kohn-Sham matrix). We show that with this algorithm (i) single point calculations on very large systems (millions of atoms) can be performed on large SMP machines, (ii) calculations involving intermediate size systems (1000-100 000 atoms) are also strongly accelerated and can run efficiently on standard servers, and (iii) the error on the total energy due to the use of a cutoff in the molecular orbital coefficients can be controlled such that it remains smaller than the SCF convergence criterion.
authors.affiliation: Laboratoire de Chimie et Physique Quantiques, Université de Toulouse-CNRS-IRSAMC , 31062 Toulouse Cedex 04, France.
authors.forename: Anthony
authors.initials: A
authors.lastname: Scemama
authors.affiliation: CALMIP, Université de Toulouse-CNRS-INPT-INSA-UPS , F-31062 Toulouse Cedex 4, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Renon
authors.affiliation: Laboratoire de Chimie et Physique Quantiques, Université de Toulouse-CNRS-IRSAMC , 31062 Toulouse Cedex 04, France.
authors.forename: Mathias
authors.initials: M
authors.lastname: Rapacioli