Convergence

Name ConvAbsDens
Section SCF::Convergence
Type float
Default 0.0

Absolute convergence of the density:

$\varepsilon = \int {\rm d}^3r \left| \rho^{out}(\bf r) -\rho^{inp}(\bf r) \right|$.

A zero value (the default) means do not use this criterion.

If this criterion is used, the SCF loop will only stop once it is fulfilled for two consecutive iterations.

Name ConvAbsEv
Section SCF::Convergence
Type float
Default 0.0

Absolute convergence of the sum of the eigenvalues:

$ \varepsilon = \left| \sum_{j=1}^{N_{occ}} \varepsilon_j^{out} - \sum_{j=1}^{N_{occ}} \varepsilon_j^{inp} \right| $

A zero value (the default) means do not use this criterion.

If this criterion is used, the SCF loop will only stop once it is fulfilled for two consecutive iterations.

Name ConvEigenError
Section SCF::Convergence
Type logical
Default false

If true, the calculation will not be considered converged unless all states have individual errors less than EigensolverTolerance.

If this criterion is used, the SCF loop will only stop once it is fulfilled for two consecutive iterations.

Name ConvEnergy
Section SCF::Convergence
Type float
Default 0.0

Stop the SCF when the magnitude of change in energy during at one SCF iteration is smaller than this value.

If this criterion is used, the SCF loop will only stop once it is fulfilled for two consecutive iterations.

Name ConvRelDens
Section SCF::Convergence
Type float
Default 1e-6

Relative convergence of the density:

$\varepsilon = \frac{1}{N} \mathrm{ConvAbsDens}$.

N is the total number of electrons in the problem. A zero value means do not use this criterion.

If you reduce this value, you should also reduce EigensolverTolerance to a value of roughly 1/10 of ConvRelDens to avoid convergence problems.

If this criterion is used, the SCF loop will only stop once it is fulfilled for two consecutive iterations.

Name ConvRelEv
Section SCF::Convergence
Type float
Default 0.0

Relative convergence of the sum of the eigenvalues:

$\varepsilon = \frac{ \left| \sum_{j=1}^{N_{occ}} ( \varepsilon_j^{out} - \varepsilon_j^{inp} ) \right|} {\left| \sum_{j=1}^{N_{occ}} \varepsilon_j^{out} \right|} $

If this criterion is used, the SCF loop will only stop once it is fulfilled for two consecutive iterations.

Name MaximumIter
Section SCF::Convergence
Type integer
Default 200

Maximum number of SCF iterations. The code will stop even if convergence has not been achieved. -1 means unlimited. 0 means just do LCAO (or read from restart), compute the eigenvalues and energy, and stop, without updating the wavefunctions or density.

If convergence criteria are set, the SCF loop will only stop once the criteria are fulfilled for two consecutive iterations.

Note that this variable is also used in the section Calculation Modes::Unoccupied States, where it denotes the maximum number of calls of the eigensolver. In this context, the default value is 50.

Name MaximumIterBerry
Section SCF::Convergence
Type integer
Default 10

Maximum number of iterations for the Berry potential, within each SCF iteration. Only applies if a StaticElectricField is applied in a periodic direction. The code will move on to the next SCF iteration even if convergence has not been achieved. -1 means unlimited.