Section OUTER_SCF

• parameters controlling the outer SCF loop

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / XAS / SCF / OUTER_SCF

• This section cannot be repeated.

• Subsections

  • CDFT_OPT

• Keywords

  • SECTION_PARAMETERS
  • BISECT_TRUST_COUNT
  • DIIS_BUFFER_LENGTH
  • EPS_SCF
  • EXTRAPOLATION_ORDER
  • MAX_SCF
  • OPTIMIZER
  • STEP_SIZE
  • TYPE

• Keyword descriptions

  SECTION_PARAMETERS
  	&OUTER_SCF {Logical}
  	controls the activation of the outer SCF loop
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  BISECT_TRUST_COUNT
  	BISECT_TRUST_COUNT {Integer}
  	Maximum number of times the same point will be used in bisection, a small number guards against the effect of wrongly converged states.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 10

  DIIS_BUFFER_LENGTH
  	DIIS_BUFFER_LENGTH {Integer}
  	Maximum number of DIIS vectors used
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 3

  EPS_SCF
  	EPS_SCF {Real}
  	The target gradient of the outer SCF variables. Notice that the EPS_SCF of the inner loop also determines the value that can be reached in the outer loop, typically EPS_SCF of the outer loop must be smaller than or equal to EPS_SCF of the inner loop.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-005

  EXTRAPOLATION_ORDER
  	EXTRAPOLATION_ORDER {Integer}
  	Number of past states used in the extrapolation of the variables during e.g. MD
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 3

  MAX_SCF
  	MAX_SCF {Integer}
  	The maximum number of outer loops
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 50

  OPTIMIZER
  	OPTIMIZER {Keyword}
  	Method used to bring the outer loop to a stationary point
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: NONE
  	List of valid keywords: BISECT Bisection of the gradient, useful for difficult one dimensional cases BROYDEN Broyden's method. Variant defined in BROYDEN_TYPE. DIIS Uses a Direct Inversion in the Iterative Subspace method NEWTON Newton's method. Only compatible with CDFT constraints. NEWTON_LS Newton's method with backtracking line search to find the optimal step size. Only compatible with CDFT constraints. Starts from the regular Newton solution and successively reduces the step size until the L2 norm of the CDFT gradient decreases or MAX_LS steps is reached. Potentially very expensive because each iteration performs a full SCF calculation. NONE Do nothing, useful only with the none type SD Takes steps in the direction of the gradient, multiplied by step_size SECANT Secant method. Only for one dimensional cases. See Broyden for multidimensional cases.

  STEP_SIZE
  	STEP_SIZE {Real}
  	The initial step_size used in the optimizer (currently steepest descent). Note that in cases where a sadle point is sought for (constrained DFT), this can be negative. For Newton and Broyden optimizers, use a value less/higher than the default 1.0 (in absolute value, the sign is not significant) to active an under/overrelaxed optimizer.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 5.00000000E-001

  TYPE
  	TYPE {Keyword}
  	Specifies which kind of outer SCF should be employed
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: NONE
  	List of valid keywords: BASIS_CENTER_OPT Optimize positions of basis functions, if atom types FLOATING_BASIS_CENTER are defined CDFT_CONSTRAINT Enforce a constraint on a generic CDFT weight population. Requires the corresponding section QS&CDFT which determines the type of weight used. DDAPC_CONSTRAINT Enforce a constraint on the DDAPC, requires the corresponding section NONE Do nothing in the outer loop, useful for resetting the inner loop, S2_CONSTRAINT Enforce a constraint on the S2, requires the corresponding section