# extrapolation

Specify details of the Fock/density/wavefunction extrapolation scheme for accelerating ab initio molecular dynamics simulations. This command can appear in the global context.

### Options

n_steps

Number of previous MD steps used for extrapolation.

• The type is int
• The default is 12
• The value must be nonnegative
polynomial_degree

The degree of the polynomial used for extrapolation.

• The type is int
• The default is 6
• The value must be nonnegative
type

Specify the type of extrapolation.

• The type is string
• The default is FMD
• The value must be one of:
• none - Do not use extrapolation. Use the SAD guess at every step.
• FMD - Use the Fock matrix dynamics (FMD) of Pulay and Fogarasi (CPL, 386, 272–278 (2004)).
• TR - Use the time-reversible extrapolation of Niklasson et al. (PRL, 97, 123001 (2006)).
• ASPC - Use the Always-Stable-Predictor-Corrector method (Comp. Phys. Comm. 167 : 103–128 (2005))