CURVY_STEPS

References: Shao2003

Specifies the parameters of the linear scaling SCF routines [Edit on GitHub]

Keywords

FILTER_FACTOR
FILTER_FACTOR_SCALE
LINE_SEARCH
MIN_FILTER
MIN_HESSIAN_SHIFT
N_BCH_HISTORY

Keyword descriptions

FILTER_FACTOR

Type: real
Default: 1.00000000E+000
Usage: FILTER_FACTOR 10.0

Description: Allows to set a separate EPS_FILTER in the newton iterations. The new EPS is EPS_FILTER*FILTER_FACTOR.

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FILTER_FACTOR_SCALE

Type: real
Default: 1.00000000E+000
Usage: FILTER_FACTOR_SCALE 0.5

Description: Allows for dynamic EPS_FILTER. Updates the filter factor every SCF-Newton step by FILTER_FACTOR=FILTER_FACTOR*FILTER_FACTOR_SCALE

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LINE_SEARCH

Type: enum
Default: 3POINT
Usage: LINE_SEARCH 3POINT

Description: Line serch type used in the curvy_setp optimization.

Valid values:

3POINT Performs a three point line search
3POINT_2D Only for spin unrestricted calcualtions. Separate step sizes for alpha and beta spin using a fit to a 2D parabolic function

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MIN_FILTER

Type: real
Default: 1.00000000E+000
Usage: MIN_FILTER 1.0

Description: Lowest EPS_FILTER in dynamic filtering. Given as multiple of EPS_FILTER: EPS_FILTER_MIN=EPS_FILTER*MIN_FILTER

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MIN_HESSIAN_SHIFT

Type: real
Default: 0.00000000E+000
Usage: MIN_HESSIAN_SHIFT 0.0

Description: Minimal eigenvalue shift for the Hessian in the Newton iteration. Useful for small band gap systems (0.5-1.0 recommended).

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N_BCH_HISTORY

Type: integer
Default: 7
Usage: N_BCH_HISTORY 5

Description: Number of stored matrices in the Baker-Campbell-Hausdorff series. Reduces the BCH evaluation during line search but can be memory intense.

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