Section CPHF

• Parameters influencing the solution of the Z-vector equations in MP2 gradients calculations.

• Section path: CP2K_INPUT / ATOM / METHOD / XC / WF_CORRELATION / CANONICAL_GRADIENTS / CPHF

• This section cannot be repeated.

• This section cites the following reference: [DelBen2013]

• Subsections

  • none

• Keywords

  • DO_POLAK_RIBIERE
  • ENFORCE_DECREASE
  • EPS_CONV
  • MAX_ITER
  • RECALC_RESIDUAL
  • RESTART_EVERY
  • SCALE_STEP_SIZE
  • SOLVER_METHOD

• Keyword descriptions

  DO_POLAK_RIBIERE
  	DO_POLAK_RIBIERE {Logical}
  	Use a Polak-Ribiere update of the search vector in CG instead of the Fletcher Reeves update. Improves the convergence with modified step sizes. Ignored with other methods than CG.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  ENFORCE_DECREASE
  	ENFORCE_DECREASE {Logical}
  	Restarts if residual does not decrease.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  EPS_CONV
  	EPS_CONV {Real}
  	Convergence threshold for the solution of the Z-vector equations. The Z-vector equations have the form of a linear system of equations Ax=b, convergence is achieved when |Ax-b|<=EPS_CONV.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-004

  MAX_ITER
  	MAX_ITER {Integer}
  	Maximum number of iterations allowed for the solution of the Z-vector equations.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 30
  	Alias names for this keyword: MAX_NUM_ITER

  RECALC_RESIDUAL
  	RECALC_RESIDUAL {Logical}
  	Recalculates residual in every step.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  RESTART_EVERY
  	RESTART_EVERY {Integer}
  	Restart iteration every given number of steps.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 5

  SCALE_STEP_SIZE
  	SCALE_STEP_SIZE {Real}
  	Scaling factor of each step.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E+000

  SOLVER_METHOD
  	SOLVER_METHOD {Keyword}
  	Chose solver of the z-vector equations.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: POPLE
  	List of valid keywords: CG Conjugated gradient method (equivalent to Pople). POPLE Pople's method (Default). RICHARDSON Richardson iteration SD Steepest Descent iteration