Section LS_SOLVER

• Specifies the parameters of the linear scaling solver routines

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / ENERGY_CORRECTION / LS_SOLVER

• This section cannot be repeated.

• This section cites the following reference: [VandeVondele2012]

• Subsections

  • none

• Keywords

  • CHECK_S_INV
  • DYNAMIC_THRESHOLD
  • EPS_FILTER
  • EPS_LANCZOS
  • EXTRAPOLATION_ORDER
  • FIXED_MU
  • MATRIX_CLUSTER_TYPE
  • MAX_ITER_LANCZOS
  • MU
  • NON_MONOTONIC
  • REPORT_ALL_SPARSITIES
  • SIGN_METHOD
  • SIGN_ORDER
  • SINGLE_PRECISION_MATRICES
  • S_INVERSION
  • S_PRECONDITIONER
  • S_SQRT_METHOD
  • S_SQRT_ORDER

• Keyword descriptions

  CHECK_S_INV
  	CHECK_S_INV {Logical}
  	Perform an accuracy check on the inverse/sqrt of the s matrix.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  DYNAMIC_THRESHOLD
  	DYNAMIC_THRESHOLD {Logical}
  	Should the threshold for the purification be chosen dynamically
  	This 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 {Real}
  	Threshold used for filtering matrix operations.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-006

  EPS_LANCZOS
  	EPS_LANCZOS {Real}
  	Threshold used for lanczos estimates.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-003

  EXTRAPOLATION_ORDER
  	EXTRAPOLATION_ORDER {Integer}
  	Number of previous matrices used for the ASPC extrapolation of the initial guess. 0 implies that an atomic guess is used at each step. low (1-2) will result in a drift of the constant of motion during MD. high (>5) might be somewhat unstable, leading to more SCF iterations.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 4

  FIXED_MU
  	FIXED_MU {Logical}
  	Should the calculation be performed at fixed chemical potential, or should it be found fixing the number of electrons
  	This 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 {Keyword}
  	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 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_ITER_LANCZOS
  	MAX_ITER_LANCZOS {Integer}
  	Maximum number of lanczos iterations.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 128

  MU
  	MU {Real}
  	Value (or initial guess) for the chemical potential, i.e. some suitable energy between HOMO and LUMO energy.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: -1.00000000E-001

  NON_MONOTONIC
  	NON_MONOTONIC {Logical}
  	Should the purification be performed non-monotonically. Relevant for TC2 only.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .TRUE.

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

  SIGN_METHOD
  	SIGN_METHOD {Keyword}
  	Method used for the computation of the sign matrix.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: NEWTONSCHULZ
  	List of valid keywords: NEWTONSCHULZ Newton-Schulz iteration. PROOT p-th order root iteration
  	This keyword cites the following references: [Niklasson2003] [VandeVondele2012]

  SIGN_ORDER
  	SIGN_ORDER {Integer}
  	Order of the method used for the computation of the sign matrix.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 2

  SINGLE_PRECISION_MATRICES
  	SINGLE_PRECISION_MATRICES {Logical}
  	Matrices used within the LS code can be either double or single precision.
  	This 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_INVERSION {Keyword}
  	Method used to compute the inverse of S.
  	This 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 {Keyword}
  	Preconditions S with some appropriate form.
  	This 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

  S_SQRT_METHOD
  	S_SQRT_METHOD {Keyword}
  	Method for the caclulation of the sqrt of S.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: NEWTONSCHULZ
  	List of valid keywords: NEWTONSCHULZ Using a Newton-Schulz-like iteration PROOT Using the p-th root method.

  S_SQRT_ORDER
  	S_SQRT_ORDER {Integer}
  	Order of the iteration method for the calculation of the sqrt of S.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 3
  	Alias names for this keyword: SIGN_SQRT_ORDER