LBFGS

References: Byrd1995

Provides parameters to tune the limited memory BFGS (LBFGS) optimization [Edit on GitHub]

Keywords

MAX_F_PER_ITER
MAX_H_RANK
PRINT_LEVEL
TRUST_RADIUS
WANTED_PROJ_GRADIENT
WANTED_REL_F_ERROR
__CONTROL_VAL

Keyword descriptions

MAX_F_PER_ITER

Type: integer
Default: 20
Usage: MAX_F_PER_ITER {integer}

Description: Maximum number of force evaluations per iteration (used for the line search)

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MAX_H_RANK

Type: integer
Default: 5
Usage: MAX_H_RANK {integer}

Description: Maximum rank (and consequently size) of the approximate Hessian matrix used by the LBFGS optimizer. Larger values (e.g. 30) will accelerate the convergence behaviour at the cost of a larger memory consumption.

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PRINT_LEVEL

Type: enum
Default: LOW
Usage: PRINT_LEVEL MEDIUM

Description: How much output is written out by the LBFGS algorithm. Currently this is independent of the &GLOBAL/PRINT_LEVEL setting.

Valid values:

SILENT Almost no output
LOW Little output about f and |proj g| every iteration
MEDIUM Quite some output about details every iteration
HIGH Lots of output about changes of active set and final x
DEBUG Everything is written out, useful for debugging purposes only

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TRUST_RADIUS

Type: real
Default: -5.29177209E-001 [angstrom]
Usage: TRUST_RADIUS {real}

Description: Trust radius used in LBFGS. Not completely in depth tested. Negativ values means no trust radius is used.

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WANTED_PROJ_GRADIENT

Type: real
Default: 1.00000000E-016 [internal_cp2k]
Usage: WANTED_PROJ_GRADIENT {real}

Description: Convergence criterion (overrides the general ones): Requested norm threshold of the gradient multiplied by the approximate Hessian.

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WANTED_REL_F_ERROR

Type: real
Default: 1.00000000E-016 [internal_cp2k]
Usage: WANTED_REL_F_ERROR {real}

Description: Convergence criterion (overrides the general ones): Requested relative error on the objective function of the optimizer (the energy)

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__CONTROL_VAL

Type: integer
Default: -1

Description: Hidden parameter that controls the printing behavior of the LBFGS optimizer for advanced debug purposes. This option overrides PRINT_LEVEL setting if explicit.

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