Mixing self-consistent quantities

Mixing various quantities in self-consistent manners are quite frequent. This module enables a variety of methods based on the Pulay (DIIS) mixing methods and may be used for externally driven SC cycles.

Container classes

Mixing makes use of so called metrics and several steps of quantities stored in history.

The basic classes that are used internally are

History([history])	A history class for retaining a set of history elements
BaseMixer([weight])	Base class mixer
BaseHistoryMixer([weight, history])	Base class mixer with history

Mixing algorithms

LinearMixer([weight])	Linear mixing
DIISMixer([weight, history, metric])	Direct inversion of the iterative subspace (DIIS mixing)
PulayMixer([weight, history, metric])
AdaptiveDIISMixer([weight, history, metric])	Adapt the mixing weight according to the Lagrange multiplier
AdaptivePulayMixer([weight, history, metric])