Open AccessUnconstrained energy functionals for electronic structure calculations
Author(s) -
Bernd Pfrommer,
James Demmel,
Horst D. Simon
Publication year - 1998
Language(s) - English
Resource type - Reports
DOI - 10.2172/663269
Subject(s) - orthonormality , convergence (economics) , conjugate gradient method , context (archaeology) , energy functional , energy (signal processing) , electronic structure , mathematics , statistical physics , computer science , algorithm , physics , mathematical analysis , quantum mechanics , orthonormal basis , paleontology , statistics , economics , biology , economic growth
The performance of conjugate gradient schemes for minimizing unconstrained energy functionals in the context of electronic structure calculations is studied. The unconstrained functionals allow a straightforward application of conjugate gradients by removing the explicit orthonormality constraints on the quantum-mechanical wave functions. However, the removal of the constraints can lead to slow convergence, in particular when preconditioning is used. The convergence properties of two previously suggested energy functionals are analyzed, and a new functional is proposed, which unifies some of the advantages of the other functionals. A numerical example confirms the analysis