Minimisation methods

$\{ \phi_i({\bf r}) \}$ variation:

• account for non-orthogonal localised functions (not shown here)
• and non-orthogonal basis set
• kinetic energy preconditioningused to compress eigenvalue spectrum
• currently investigating use of methods based upon the Arnoldi factorisation to solve unsymmetric eigenvalue problem for the $\{ \phi_i({\bf r}) \}$