Section CPHF

• Parameters influencing the solution of the Z-vector equations in low-scaling Laplace-SOS-MP2 gradients calculations.

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / ENERGY_CORRECTION / XC / WF_CORRELATION / LOW_SCALING / CPHF

• This section cannot be repeated.

• Subsections

  • none

• Keywords

  • ENERGY_GAP
  • EPS_CONV
  • MAX_ITER
  • PRECONDITIONER

• Keyword descriptions

  ENERGY_GAP
  	ENERGY_GAP {Real}
  	Energy gap estimate [a.u.] for preconditioning
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 2.00000000E-001

  EPS_CONV
  	EPS_CONV {Real}
  	Target accuracy for Z-vector euation solution.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-006

  MAX_ITER
  	MAX_ITER {Integer}
  	Maximum number of conjugate gradient iteration to be performed for one optimization.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 50

  PRECONDITIONER
  	PRECONDITIONER {Keyword}
  	Type of preconditioner to be used with all minimization schemes. They differ in effectiveness, cost of construction, cost of application. Properly preconditioned minimization can be orders of magnitude faster than doing nothing.
  	This 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, requires the ENERGY_GAP parameter to be an underestimate of the HOMO-LUMO gap. This preconditioner is recommended for almost all systems, except very large systems where make_preconditioner would dominate the total computational cost. FULL_KINETIC Cholesky inversion of S and T, fast construction, robust, and relatively good, use for very large systems. FULL_SINGLE Based on H-eS diagonalisation, not as good as FULL_ALL, but somewhat cheaper to apply. 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. FULL_S_INVERSE Cholesky inversion of S, not as good as FULL_KINETIC, yet equally expensive. NONE skip preconditioning