Section CDFT

• Parameters needed to set up a constrained DFT calculation. The constraint(s) is (are) converged in a separate external SCF loop with settings read from the OUTER_SCF section. Supported constraints: Gaussian Hirshfeld (partial) and Becke.

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / QS / CDFT

• This section cannot be repeated.

• This section cites the following reference: [Holmberg2017]

• Subsections

  • HIRSHFELD_CONSTRAINT
  • OUTER_SCF

• Keywords

  • COUNTER
  • MAX_REUSE
  • PRECOND_FREQ
  • PURGE_FREQ
  • PURGE_HISTORY
  • PURGE_OFFSET
  • REUSE_PRECOND
  • TYPE_OF_CONSTRAINT

• Keyword descriptions

  COUNTER
  	COUNTER {Integer}
  	A counter to track the total number of energy evaluations. Needed by some optimizers to print information. Useful mainly for restarts.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0

  MAX_REUSE
  	MAX_REUSE {Integer}
  	Determines how many times a previously built preconditioner can be reused.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0

  PRECOND_FREQ
  	PRECOND_FREQ {Integer}
  	See REUSE_PRECOND.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0

  PURGE_FREQ
  	PURGE_FREQ {Integer}
  	See PURGE_HISTORY.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 1

  PURGE_HISTORY
  	PURGE_HISTORY {Logical}
  	Purge wavefunction and constraint history to improve SCF convergence during MD.Counts how often the convergence of the first CDFT SCF iteration takes 2 or more outer SCF iterations and purges the history if the counter exceeds PURGE_FREQ, and PURGE_OFFSET MD steps have passed since the last purge. The counter is zeroed after each purge.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  PURGE_OFFSET
  	PURGE_OFFSET {Integer}
  	See PURGE_HISTORY.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 1

  REUSE_PRECOND
  	REUSE_PRECOND {Logical}
  	Reuse a previously built OT preconditioner between subsequent CDFT SCF iterations if the inner OT SCF loop converged in PRECOND_FREQ steps or less. Intended mainly for MD simulations with the FULL_ALL preconditioner to speed up the final iterations of the CDFT 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.

  TYPE_OF_CONSTRAINT
  	TYPE_OF_CONSTRAINT {Keyword}
  	Specifies the type of constraint used.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: NONE
  	List of valid keywords: BECKE Becke constraint. Requires corresponding section in &QS. HIRSHFELD Hirshfeld-type constraint defined by constraint atom centered spherical Gaussians Partial implementation: no forces or coupling. Requires corresponding section. NONE No constraint (disables section).