CheFSI input documentation

Initialize with stopping criteria and filter order.

Used to initialize class qimpy.electrons.CheFSI.

YAML template:

n-iterations: 100     # Number of diagonalization iterations.
eig-threshold: 1e-08  # Convergence threshold on eigenvalues in Hartrees.
filter-order: 10      # Order of the Chebyshev filter.
init-threshold: 0.1   # Eigenvalue threshold for initial Davidson steps.

Parameters:

n-iterations

Type: int, Default: 100

Number of diagonalization iterations. This only affects fixed-Hamiltonian calculations because the self-consistent field method overrides this when diagonalizing in an inner loop.

eig-threshold

Type: float, Default: 1e-08

Convergence threshold on eigenvalues in Hartrees. Stop when the maximum change in any eigenvalue between iterations falls below this threshold. This only affects fixed-Hamiltonian calculations because the self-consistent field method overrides this when diagonalizing in an inner loop.

filter-order

Type: int, Default: 10

Order of the Chebyshev filter. This amounts to the number of Hamiltonian evaluations per band per eigenvalue iteration.

init-threshold

Type: float, Default: 0.1

Eigenvalue threshold for initial Davidson steps. This controls the accuracy of a coarse Davidson diagonalization that creates a reasonable starting point for CheFSI.