forte2.orbitals.semicanonicalizer
=================================

.. py:module:: forte2.orbitals.semicanonicalizer




Module Contents
---------------

.. py:class:: Semicanonicalizer(system: forte2.system.System, mo_space: forte2.state.MOSpace | forte2.state.EmbeddingMOSpace = None, mix_inactive: bool = False, mix_active: bool = False, do_frozen: bool = True, do_active: bool = True)

   
   Class to perform semicanonicalization of a set of molecular orbitals.
   The semi-canonical basis is defined as a basis where the generalized Fock matrix
   is diagonal in a set of subspaces.


   :Parameters:

       **mo_space** : MOSpace
           The molecular orbital space defining the subspaces.

       **system** : System
           The system object containing the basis set and other properties.

       **mix_inactive** : bool, optional, default=False
           If True, frozen_core and core orbitals will be diagonalized together,
           virtual and frozen_virt also will be diagonalized together.

       **mix_active** : bool, optional, default=False
           If True, all GAS active orbitals will be diagonalized together.

   :Attributes:

       **fock** : np.ndarray
           The generalized Fock matrix in the original basis.

       **fock_semican** : np.ndarray
           The generalized Fock matrix in the semi-canonical basis.

       **eps_semican** : np.ndarray
           The diagonal entries of the Fock matrix in the semi-canonical basis.

       **C_semican** : np.ndarray
           The molecular orbital coefficients in the semi-canonical basis.

       **U** : np.ndarray
           The unitary transformation matrix from the original to the semi-canonical basis.

       **Uactv** : np.ndarray
           The unitary transformation matrix within the active space.










   .. rubric:: Notes

   The generalized Fock matrix is defined as

   .. math::
       f_p^q = h_p^q + \sum_{ij}^{\mathbf{H}}v_{pi}^{qj}\gamma_j^i,

   where :math:`\mathbf{H}` is the set of hole orbitals (i.e., all orbitals that are not unoccupied).
   The task of the `Semicanonicalizer` class is then to form the generalized Fock matrix
   and accumulate unitary transformations that diagonalizes the Fock matrix in the specified subspaces.
   If a subspace is to be untouched, the corresponding subblock of unitary transformation is set to the identity.



   ..
       !! processed by numpydoc !!

   .. py:attribute:: mo_space
      :value: None



   .. py:attribute:: two_component


   .. py:attribute:: system


   .. py:attribute:: fock_builder


   .. py:attribute:: mix_inactive
      :value: False



   .. py:attribute:: mix_active
      :value: False



   .. py:attribute:: do_frozen
      :value: True



   .. py:attribute:: do_active
      :value: True



   .. py:method:: semi_canonicalize(g1, C_contig)

      
      Perform the semi-canonicalization.


      :Parameters:

          **g1** : np.ndarray
              The active space 1-electron density matrix in the molecular orbital basis. 
              Spin-summed if non-relativistic, spin-orbital if relativistic.

          **C_contig** : np.ndarray
              The molecular orbital coefficients, in the "contiguous" order of the orbitals.
              Note that all other quantities are also defined in this order.














      ..
          !! processed by numpydoc !!