Section DAVIDSON

• Without description, yet.

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / SCF / DIAGONALIZATION / DAVIDSON

• This section cannot be repeated and can be optional.

• Subsections

  • none

• Keywords

  • CONV_MOS_PERCENT
  • ENERGY_GAP
  • FIRST_PREC
  • NEW_PREC_EACH
  • PRECONDITIONER
  • PRECOND_SOLVER
  • SPARSE_MOS

• Keyword descriptions

  CONV_MOS_PERCENT
  	CONV_MOS_PERCENT 0.8
  	Minimal percent of MOS that have to converge within the Davidson loop before the SCF iteration is completed and a new Hamiltonian is computed
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 5.00000000E-01

  ENERGY_GAP
  	ENERGY_GAP 0.001
  	Should be an estimate for the energy gap [a.u.] (HOMO-LUMO) and is used in preconditioning, especially effective with the FULL_ALL preconditioner, in which case it should be an underestimate of the gap (0.001 doing normally fine). For the other preconditioners, making this value larger (0.2) will tame the preconditioner in case of poor initial guesses.
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 2.00000000E-01

  FIRST_PREC
  	FIRST_PREC 1
  	First SCF iteration at which a Preconditioner is employed
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 1

  NEW_PREC_EACH
  	NEW_PREC_EACH 10
  	Number of SCF iterations after which a new Preconditioner is computed
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 20

  PRECONDITIONER
  	PRECONDITIONER FULL_ALL
  	Type of preconditioner to be used with all minimization schemes.
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: FULL_ALL
  	List of valid keywords: FULL_ALL Most effective state selective preconditioner based on diagonalization FULL_SINGLE_INVERSE Based on H-eS cholesky inversion, similar to FULL_SINGLE in preconditioning efficiency but cheaper to construct, might be somewhat less robust. Recommended for large systems. NONE skip preconditioning
  	This keyword cites the following reference: [VandeVondele2003]

  PRECOND_SOLVER
  	PRECOND_SOLVER DIRECT
  	How the preconditioner is applied to the residual.
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: DEFAULT
  	List of valid keywords: DEFAULT the default DIRECT Cholesky decomposition followed by triangular solve (works for FULL_KINETIC/SINGLE_INVERSE/S_INVERSE) INVERSE_CHOLESKY Cholesky decomposition followed by explicit inversion (works for FULL_KINETIC/SINGLE_INVERSE/S_INVERSE) SAINV SAINV inversion (works for FULL_KINETIC/SINGLE_INVERSE/S_INVERSE)

  SPARSE_MOS
  	SPARSE_MOS
  	Use MOS as sparse matrix and avoid as much as possible multiplications with full matrices
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .TRUE.