CPHF

Parameters influencing the solution of the Z-vector equations in low-scaling Laplace-SOS-MP2 gradients calculations. [Edit on GitHub]

Keywords

• ENERGY_GAP

• EPS_CONV

• MAX_ITER

• PRECONDITIONER

Keyword descriptions

ENERGY_GAP: real = 2.00000000E-001

Usage: ENERGY_GAP 0.1

Energy gap estimate [a.u.] for preconditioning [Edit on GitHub]

EPS_CONV: real = 1.00000000E-006

Usage: EPS 1.e-6

Target accuracy for Z-vector euation solution. [Edit on GitHub]

MAX_ITER: integer = 50

Usage: MAX_ITER 200

Maximum number of conjugate gradient iteration to be performed for one optimization. [Edit on GitHub]

PRECONDITIONER: enum = FULL_ALL

Usage: PRECONDITIONER FULL_ALL

Valid values:

• 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_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_SINGLE Based on H-eS diagonalisation, not as good as FULL_ALL, but somewhat cheaper to apply.

• FULL_KINETIC Cholesky inversion of S and T, fast construction, robust, and relatively good, use for very large systems.

• FULL_S_INVERSE Cholesky inversion of S, not as good as FULL_KINETIC, yet equally expensive.

• NONE skip preconditioning

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. [Edit on GitHub]