# KRYLOV

[Edit on GitHub]

## Keywords

- CHECK_MOS_CONV

- EPS_KRYLOV

- EPS_STD_DIAG

- NBLOCK

- NKRYLOV

## Keyword descriptions

CHECK_MOS_CONV: logical = F

  Lone keyword: `T`

  Usage: CHECK_MOS_CONV T

  This requires to check the convergence of MOS also when standard diagonalization steps are performed, if the block krylov approach is active. [Edit on GitHub]

EPS_KRYLOV: real = 1.00000000E-007

  Usage: EPS_KRYLOV 0.00001

  Convergence criterion for the MOs [Edit on GitHub]

EPS_STD_DIAG: real = -1.00000000E+000

  Usage: EPS_STD_DIAG 0.001

  Level of convergence to be reached before starting the Lanczos procedure. Above this threshold a standard diagonalization method is used. If negative Lanczos is started at the first iteration [Edit on GitHub]

NBLOCK: integer = 32

  Usage: NBLOCK 1

  Size of the block of vectors refined simultaneously by the Lanczos procedure [Edit on GitHub]

NKRYLOV: integer = 4

  Usage: NKRYLOV 20

  Dimension of the Krylov space used for the Lanczos refinement [Edit on GitHub]