Section BFGS

• Provides parameters to tune the BFGS optimization

• Section path: CP2K_INPUT / MOTION / GEO_OPT / TRANSITION_STATE / DIMER / ROT_OPT / BFGS

• This section cannot be repeated and can be optional.

• Subsections

  • RESTART

• Keywords

  • RESTART_FILE_NAME
  • RESTART_HESSIAN
  • TRUST_RADIUS
  • USE_MODEL_HESSIAN
  • USE_RAT_FUN_OPT

• Keyword descriptions

  RESTART_FILE_NAME
  	RESTART_FILE_NAME {FILENAME}
  	Specifies the name of the file used to read the initial Hessian.
  	This optional keyword cannot be repeated and it expects precisely one string.

  RESTART_HESSIAN
  	RESTART_HESSIAN
  	Controls the reading of the initial Hessian from file.
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  TRUST_RADIUS
  	TRUST_RADIUS {REAL}
  	Trust radius used in BFGS. Previously set to 0.1. Large values can lead to instabilities
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 2.50000000E-01
  	Default unit: [angstrom]

  USE_MODEL_HESSIAN
  	USE_RAT_FUN_OPT
  	Uses a model Hessian as initial guess instead of a unit matrix. Should lead in general to improved convergence might be switched off for exotic cases
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .FALSE.
  	Default value: .TRUE.

  USE_RAT_FUN_OPT
  	USE_RAT_FUN_OPT
  	Includes a rational function optimization to determine the step. Previously default but did not improve convergence in many cases
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.