Section PAO

• Polarized Atomic Orbital Method

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / LS_SCF / PAO

• This section cannot be repeated.

• This section cites the following references: [Berghold2002] [Schuett2018]

• Subsections

  • LINE_SEARCH
  • MACHINE_LEARNING
  • PRINT

• Keywords

  • CG_INIT_STEPS
  • CG_RESET_LIMIT
  • CHECK_GRADIENT_TOL
  • CHECK_UNITARY_TOL
  • EPS_PAO
  • EPS_PGF
  • LINPOT_INITGUESS_DELTA
  • LINPOT_PRECONDITION_DELTA
  • LINPOT_REGULARIZATION_DELTA
  • LINPOT_REGULARIZATION_STRENGTH
  • MAX_CYCLES
  • MAX_PAO
  • MIXING
  • NUM_GRADIENT_EPS
  • NUM_GRADIENT_ORDER
  • OPTIMIZER
  • PARAMETERIZATION
  • PENALTY_DISTANCE
  • PENALTY_STRENGTH
  • PRECONDITION
  • PREOPT_DM_FILE
  • REGULARIZATION
  • RESTART_FILE

• Keyword descriptions

  CG_INIT_STEPS
  	CG_INIT_STEPS {Integer}
  	Number of steepest descent steps before starting the conjugate gradients optimization.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 2

  CG_RESET_LIMIT
  	CG_RESET_LIMIT {Real}
  	The CG is reseted if the cosine of the angle between the last search direction and the new gradient is larger that the limit.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-001

  CHECK_GRADIENT_TOL
  	CHECK_GRADIENT_TOL {Real}
  	Tolerance for check of full analytic gradient against the numeric one. Negative values mean don't check at all.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: -1.00000000E+000

  CHECK_UNITARY_TOL
  	CHECK_UNITARY_TOL {Real}
  	Check if rotation matrix is unitary. Negative values mean don't check at all.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: -1.00000000E+000

  EPS_PAO
  	EPS_PAO {Real}
  	Convergence criteria for PAO optimization.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-005

  EPS_PGF
  	EPS_PGF {Real}
  	Sets precision for potential and descriptor matrix elements. Overrides DFT/QS/EPS_DEFAULT value.
  	This keyword cannot be repeated and it expects precisely one real.

  LINPOT_INITGUESS_DELTA
  	LINPOT_INITGUESS_DELTA {Real}
  	Eigenvalue threshold used for calculating initial guess.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000

  LINPOT_PRECONDITION_DELTA
  	LINPOT_PRECONDITION_DELTA {Real}
  	Eigenvalue threshold used for preconditioning.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000

  LINPOT_REGULARIZATION_DELTA
  	LINPOT_REGULARIZATION_DELTA {Real}
  	Eigenvalue threshold used for regularization.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000

  LINPOT_REGULARIZATION_STRENGTH
  	LINPOT_REGULARIZATION_STRENGTH {Real}
  	Strength of regularization on linpot layer.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000

  MAX_CYCLES
  	MAX_CYCLES {Integer}
  	Maximum number of PAO line search cycles for a given hamiltonian.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 1000

  MAX_PAO
  	MAX_PAO {Integer}
  	Maximum number of PAO basis optimization steps.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 1000

  MIXING
  	MIXING {Real}
  	Mixing fraction of new and old optimizied solutions.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 5.00000000E-001

  NUM_GRADIENT_EPS
  	NUM_GRADIENT_EPS {Real}
  	Step length used for the numeric derivative when checking the gradient.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-008

  NUM_GRADIENT_ORDER
  	NUM_GRADIENT_ORDER {Integer}
  	Order of the numeric derivative when checking the gradient. Possible values are 2, 4, and 6.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 2

  OPTIMIZER
  	OPTIMIZER {Keyword}
  	Optimizer used to find PAO basis.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: CG
  	List of valid keywords: BFGS Broyden-Fletcher-Goldfarb-Shanno algorithm CG Conjugate gradient algorithm

  PARAMETERIZATION
  	PARAMETERIZATION {Keyword}
  	Parametrization of the mapping between the primary and the PAO basis.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: ROTINV
  	List of valid keywords: EQUIVARIANT Equivariant parametrization EXP Original matrix exponential parametrization FOCK Fock matrix parametrization GTH Parametrization based on GTH pseudo potentials ROTINV Rotational invariant parametrization (machine learnable)

  PENALTY_DISTANCE
  	PENALTY_DISTANCE {Real}
  	Distance at which approaching eigenvalues are penalized to prevent degeneration.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-001

  PENALTY_STRENGTH
  	PENALTY_STRENGTH {Real}
  	Strength of the penalty term which prevents degenerate eigenvalues.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 5.00000000E-003

  PRECONDITION
  	PRECONDITION {Logical}
  	Apply a preconditioner to the parametrization.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  PREOPT_DM_FILE
  	PREOPT_DM_FILE {Word}
  	Read pre-optimized density matrix from given file.
  	This keyword cannot be repeated and it expects precisely one word.

  REGULARIZATION
  	REGULARIZATION {Real}
  	Strength of regularization term which ensures parameters remain small.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000

  RESTART_FILE
  	RESTART_FILE {Word}
  	Reads given files as restart for PAO basis
  	This keyword cannot be repeated and it expects precisely one word.