[BANANA] LA/Opt seminar Wed May 14 (Osni Marques)

[Michael A. Saunders]

   Linear Algebra and Optimization Seminar (CME510)
   iCME, Stanford University
   http://icme.stanford.edu/seminars/seminars.php

   4:15pm Wed May 14, 2008
   Room GESB 134 (Green Earth Sciences Building)

   Dr Osni Marques
   Computational Research Division, Lawrence Berkeley National Lab
   http://crd.lbl.gov/~osni/
   OAMarques at lbl.gov

A Comparison of Eigensolvers for Electronic Structure Calculations

The solution of the single-particle Schrodinger equation that arises
in electronic structure calculations often requires solving for
interior eigenstates of a large Hamiltonian.  The states at the top of
the valence band and at the bottom of the conduction band determine
the band gap that relates to important physical characteristics such
as optical or transport properties.  In order to avoid the explicit
computation of all eigenstates below the interesting ones, a folded
spectrum method has usually been employed to compute only the
eigenstates near the band gap.  In this talk, we compare the conjugate
gradient minimization, the optimal block preconditioned conjugate
gradient, the implicit restarted Lanczos, and variants of the
(Jacobi-)Davidson algorithms applied to the folded spectrum matrix for
the computation of eigenstates of interest.  We also show results for
when some of these algorithms are applied to the unfolded spectrum.

Acknowledgments: A. Canning, J. Langou, S. Tomov, C. Voemel, L.-W. Wang