Section RI

• Parameters for RI method in HFX (experimental, forces not yet implemented).

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / XC / HF / RI

• This section cannot be repeated.

• Subsections

  • LOCALIZE
  • RI_INFO

• Keywords

  • SECTION_PARAMETERS
  • 2C_MATRIX_FUNCTIONS
  • CALC_COND_NUM
  • CHECK_2C_MATRIX
  • CUTOFF_RADIUS
  • EPS_EIGVAL
  • EPS_FILTER
  • EPS_FILTER_2C
  • EPS_FILTER_MO
  • EPS_LANCZOS
  • EPS_PGF_ORB
  • EPS_STORAGE_SCALING
  • MAX_ITER_LANCZOS
  • MEMORY_CUT
  • MIN_BLOCK_SIZE
  • MIN_BLOCK_SIZE_MO
  • OMEGA
  • RI_FLAVOR
  • RI_METRIC
  • SQRT_ORDER

• Keyword descriptions

  SECTION_PARAMETERS
  	&RI {Logical}
  	controls the activation of RI
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  2C_MATRIX_FUNCTIONS
  	2C_MATRIX_FUNCTIONS {Keyword}
  	Methods for matrix inverse and matrix square root.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: CHOLESKY
  	List of valid keywords: CHOLESKY Cholesky: not stable in case of ill-conditioned RI basis DIAG Diagonalization with eigenvalue quenching: stable ITER Iterative algorithms: linear scaling Hotelling's method for inverse and Newton-Schulz iteration for matrix square root

  CALC_COND_NUM
  	CALC_COND_NUM {Logical}
  	Calculate the condition number of integral matrices.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.
  	Alias names for this keyword: CALC_CONDITION_NUMBER

  CHECK_2C_MATRIX
  	CHECK_2C_MATRIX {Logical}
  	Report accuracy for the inverse/sqrt of the 2-center integral matrix.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  CUTOFF_RADIUS
  	CUTOFF_RADIUS {Real}
  	The cutoff radius (in Angstrom) for the truncated Coulomb operator. Default is CUTOFF_RADIUS from INTERACTION_POTENTIAL.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [angstrom]

  EPS_EIGVAL
  	EPS_EIGVAL {Real}
  	Throw away linear combinations of RI basis functions with a small eigenvalue, this is applied only if 2C_MATRIX_FUNCTIONS DIAG
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-007

  EPS_FILTER
  	EPS_FILTER {Real}
  	Filter threshold for DBCSR tensor contraction.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-009

  EPS_FILTER_2C
  	EPS_FILTER_2C {Real}
  	Filter threshold for 2c integrals. Default should be kept.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-012

  EPS_FILTER_MO
  	EPS_FILTER_MO {Real}
  	Filter threshold for contraction of 3-center integrals with MOs. Default should be kept.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-012

  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

  EPS_PGF_ORB
  	EPS_PGF_ORB {Real}
  	Sets precision of the integral tensors.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-005

  EPS_STORAGE_SCALING
  	EPS_STORAGE_SCALING {Real}
  	Scaling factor to scale EPS_FILTER for storage of 3-center integrals. Storage threshold will be EPS_FILTER*EPS_STORAGE_SCALING.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-002

  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: 500

  MEMORY_CUT
  	MEMORY_CUT {Integer}
  	Memory reduction factor. For RI_FLAVOR RHO, this should be a square number (if not, the next greater square number is used).
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 9

  MIN_BLOCK_SIZE
  	MIN_BLOCK_SIZE {Integer}
  	Minimum tensor block size.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 3

  MIN_BLOCK_SIZE_MO
  	MIN_BLOCK_SIZE_MO {Integer}
  	Minimum tensor block size for MOs.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 64

  OMEGA
  	OMEGA {Real}
  	The range parameter for the short range operator (in 1/a0). Default is OMEGA from INTERACTION_POTENTIAL.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000

  RI_FLAVOR
  	RI_FLAVOR {Keyword}
  	Flavor of RI: how to contract 3-center integrals
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: RHO
  	List of valid keywords: MO with MO coefficients RHO with density matrix

  RI_METRIC
  	RI_METRIC {Keyword}
  	The type of RI operator. Default is POTENTIAL_TYPE from INTERACTION_POTENTIAL. The standard Coulomb operator cannot be used in periodic systems.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: HFX
  	List of valid keywords: COULOMB Standard Coulomb operator: 1/r HFX Same as HFX operator IDENTITY Overlap SHORTRANGE Short range: erfc(omega*r)/r TRUNCATED Truncated Coulomb operator: 1/r if (r

  SQRT_ORDER
  	SQRT_ORDER {Integer}
  	Order of the iteration method for the calculation of the sqrt of 2-center integral matrix.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 3