Section LS_SCF

• Specifies the parameters of the linear scaling SCF routines

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / LS_SCF

• This section cannot be repeated and can be optional.

• Subsections

  • none

• Keywords

  • DYNAMIC_THRESHOLD
  • EPS_FILTER
  • EPS_SCF
  • FIXED_MU
  • MATRIX_CLUSTER_TYPE
  • MAX_SCF
  • MIXING_FRACTION
  • MU
  • PERFORM_MU_SCAN
  • PURIFICATION_METHOD
  • REPORT_ALL_SPARSITIES
  • SIGN_SQRT_ORDER
  • SINGLE_PRECISION_MATRICES
  • S_INVERSION
  • S_PRECONDITIONER

• Keyword descriptions

  DYNAMIC_THRESHOLD
  	DYNAMIC_THRESHOLD .TRUE.
  	Should the threshold for the purification be chosen dynamically
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  EPS_FILTER
  	EPS_FILTER 1.0E-7
  	Threshold used for filtering matrix operations.
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-06

  EPS_SCF
  	EPS_SCF 1.E-6
  	target accuracy for the scf convergence. Change of the total energy per electron
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-07

  FIXED_MU
  	FIXED_MU .TRUE.
  	Should the calculation be performed at fixed chemical potential, or should it be found fixing the number of electrons
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  MATRIX_CLUSTER_TYPE
  	MATRIX_CLUSTER_TYPE MOLECULAR
  	Specify how atomic blocks should be clustered in the used matrices, in order to improve flop rate, and possibly speedup the matrix multiply. Note that the atomic s_preconditioner can not be used.Furthermore, since screening is on matrix blocks, slightly more accurate results can be expected with molecular.
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: ATOMIC
  	List of valid keywords: ATOMIC Using atomic blocks MOLECULAR Using molecular blocks.

  MAX_SCF
  	MAX_SCF 200
  	Maximum number of SCF iteration to be performed for one optimization
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 20

  MIXING_FRACTION
  	MIXING_FRACTION 0.4
  	Mixing density matrices uses the specified fraction in the SCF procedure.
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 4.50000000E-01

  MU
  	MU 0.0
  	Value (or initial guess) for the chemical potential, i.e. some suitable energy between HOMO and LUMO energy.
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: -1.00000000E-01

  PERFORM_MU_SCAN
  	PERFORM_MU_SCAN
  	Do a scan of the chemical potential after the SCF
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  PURIFICATION_METHOD
  	PURIFICATION_METHOD TRS4
  	Scheme used to purify the Kohn-Sham matrix into the density matrix.
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: SIGN_MATRIX
  	List of valid keywords: SIGN_MATRIX Newton-Schulz sign matrix iteration. TRS4 Trace resetting 4th order scheme

  REPORT_ALL_SPARSITIES
  	REPORT_ALL_SPARSITIES
  	Run the sparsity report at the end of the SCF
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .TRUE.

  SIGN_SQRT_ORDER
  	SIGN_SQRT_ORDER 5
  	Order of the sqrt iteration, should be 2..5, 3 or 5 recommended
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 3

  SINGLE_PRECISION_MATRICES
  	SINGLE_PRECISION_MATRICES
  	Matrices used within the LS code can be either double or single precision.
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  S_INVERSION
  	S_PRECONDITIONER MOLECULAR
  	Method used to compute the inverse of S.
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: SIGN_SQRT
  	List of valid keywords: HOTELLING Using the Hotellign iteration. SIGN_SQRT Using the inverse sqrt as obtained from sign function iterations.

  S_PRECONDITIONER
  	S_PRECONDITIONER MOLECULAR
  	Preconditions S with some appropriate form.
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: ATOMIC
  	List of valid keywords: ATOMIC Using atomic blocks MOLECULAR Using molecular sub-blocks. Recommended if molecules are defined and not too large. NONE No preconditioner