
DIAG_METHODΒΆ
This specifies which method is to be used in diagonalizing the Hamiltonian. The valid options are:
RSP
, to form the entire H matrix and diagonalize using libciomr to obtain all eigenvalues (n.b. requires HUGE memory);OLSEN
, to use Olsen’s preconditioned inverse subspace method (1990);MITRUSHENKOV
, to use a 2x2 Olsen/Davidson method; andDAVIDSON
(orSEM
) to use Liu’s Simultaneous Expansion Method, which is identical to the Davidson method if only one root is to be found. There also exists a SEM debugging mode,SEMTEST
. TheSEM
method is the most robust, but it also requiresCI vectors on disk, where
is the maximum number of iterations and
is the number of roots.
- Type: string
- Possible Values: RSP, OLSEN, MITRUSHENKOV, DAVIDSON, SEM, SEMTEST
- Default: SEM