DIAGONALIZATION

Set up type and parameters for Kohn-Sham matrix diagonalization. [Edit on GitHub]

Subsections

• DAVIDSON
• DIAG_SUB_SCF
• FILTER_MATRIX
• KRYLOV
• OT

Keywords

• SECTION_PARAMETERS

• ALGORITHM

• EPS_ADAPT

• EPS_ITER

• EPS_JACOBI

• JACOBI_THRESHOLD

• MAX_ITER

• UPDATE_METHOD

Keyword descriptions

SECTION_PARAMETERS

Type: logical
Default: F
Lone keyword: T
Usage: &DIAGONALIZATION T

Description: controls the activation of the diagonalization method [Edit on GitHub]

ALGORITHM

Type: enum
Default: STANDARD
Usage: ALGORITHM STANDARD

Description: Algorithm to be used for diagonalization [Edit on GitHub]

Valid values:

• STANDARD AO-basis Kohn-Sham diagonalization using LAPACK-compatible methods or a late-SCF Jacobi sweep.

• OT Iterative diagonalization using OT method

• LANCZOS Block Krylov-space approach to self-consistent diagonalisation

• DAVIDSON Preconditioned blocked Davidson

• FILTER_MATRIX Filter matrix diagonalization

EPS_ADAPT

Type: real
Default: 0.00000000E+000
Usage: EPS_ADAPT 0.01

Description: Tolerance of the iterative diagonalization relative to the current SCF convergence. A positive value makes the inner tolerance the looser of EPS_ITER and this factor times the SCF error: loose while the density is far from self-consistency, tightening as the SCF converges. The value 0 disables the tracking. [Edit on GitHub]

EPS_ITER

Type: real
Default: 1.00000000E-008
Usage: EPS_ITER 1.e-8

Description: Required accuracy in iterative diagonalization [Edit on GitHub]

EPS_JACOBI

Type: real
Default: 0.00000000E+000
Usage: EPS_JACOBI 1.0E-5

Description: Below this threshold value for the SCF convergence the pseudo-diagonalization method using Jacobi rotations is activated. This method is much faster than a real diagonalization and it is even speeding up while achieving full convergence. However, it needs a pre-converged wavefunction obtained by at least one real diagonalization which is further optimized while keeping the original eigenvalue spectrum. The MO eigenvalues are NOT updated. The method might be useful to speed up calculations for large systems e.g. using a semi-empirical method. [Edit on GitHub]

References: Stewart1982

JACOBI_THRESHOLD

Type: real
Default: 1.00000000E-007
Usage: JACOBI_THRESHOLD 1.0E-6

Description: Controls the accuracy of the pseudo-diagonalization method using Jacobi rotations [Edit on GitHub]

References: Stewart1982

MAX_ITER

Type: integer
Default: 2
Usage: MAX_ITER 20

Description: Maximum number of iterations in iterative diagonalization [Edit on GitHub]

UPDATE_METHOD

Type: enum
Default: MIXING
Usage: UPDATE_METHOD ADIIS

Description: Selects the SCF update method used with diagonalization. MIXING uses the existing density-mixing and DIIS workflow; ADIIS uses augmented-DIIS Fock-space interpolation and accepts the diagonalized density directly. [Edit on GitHub]

Valid values:

• MIXING Use the existing density-mixing SCF workflow

• ADIIS Use augmented-DIIS Fock-space interpolation

References: Hu2010