========
davidson
========
Abstract module for Davidson's diagonalization.
It contains everything required for the Davidson algorithm, dressed or
not. If a dressing is used, the dressing column should be defined and
the :ref:`module_davidson_dressed` module should be used. If no dressing
is required, the :ref:`module_davidson` module should be used, and it
has a default zero dressing vector.
The important providers for that module are:
#. :c:data:`psi_energy` which is the expectation value over the wave
function (:c:data:`psi_det`, :c:data:`psi_coef`) of the Hamiltonian,
dressed or not. It uses the general subroutine :c:func:`u_0_H_u_0`.
#. :c:data:`psi_energy_two_e` which is the expectation value over the
wave function (:c:data:`psi_det`, :c:data:`psi_coef`) of the standard
two-electron Coulomb operator. It uses the general routine
:c:func:`u_0_H_u_0_two_e`.
Yann Damour
7a3379a43e