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.. _module_cisd:
.. program :: cisd
.. default-role :: option
====
cisd
====
This module contains a CI of single and double excitations.
The user point of view
----------------------
The :command: `cisd` program performs the CI of the ROHF-like + all single and double excitations on top of it.
This program can be very useful to :
* **Ground state calculations** : generate a guess for the ground state wave function if one is not sure that the :c:func: `scf` program gave the lowest SCF solution. In combination with :c:func: `save_natorb` it can produce new |MOs| in order to reperform an :c:func: `scf` optimization.
* **Excited states calculations** : generate guess for all the :option: `determinants n_states` wave functions, that will be used by the :c:func: `fci` program.
The main keywords/options to be used are:
* :option: `determinants n_states` : number of states to consider for the |cisd| calculation
* :option: `determinants s2_eig` : force all states to have the desired value of :math: `S^2`
* :option: `determinants expected_s2` : desired value of :math: `S^2`
The programmer point of view
----------------------------
This module have been built by setting the following rules:
* The only generator determinant is the Hartree-Fock (single-reference method)
* All generated determinants are included in the wave function (no perturbative
selection)
These rules are set in the `` H_apply.irp.f `` file.
EZFIO parameters
----------------
.. option :: energy
Variational |CISD| energy
Programs
--------
* :ref: `cisd`
Subroutines / functions
-----------------------
.. c:function :: h_apply_cisd:
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File : :file: `h_apply.irp.f_shell_12`
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.. code :: fortran
subroutine H_apply_cisd()
Calls H_apply on the |HF| determinant and selects all connected single and double
excitations (of the same symmetry). Auto-generated by the `` generate_h_apply `` script.
Needs:
.. hlist ::
:columns: 3
* :c:data: `psi_coef`
* :c:data: `n_states`
* :c:data: `generators_bitmask`
* :c:data: `mo_num`
* :c:data: `mo_two_e_integrals_in_map`
* :c:data: `h_apply_buffer_allocated`
* :c:data: `n_det`
* :c:data: `s2_eig`
* :c:data: `n_det_generators`
* :c:data: `i_bitmask_gen`
* :c:data: `n_int`
* :c:data: `psi_det`
* :c:data: `psi_det_generators`
* :c:data: `psi_det_generators`
Calls:
.. hlist ::
:columns: 3
* :c:func: `build_fock_tmp`
* :c:func: `copy_h_apply_buffer_to_wf`
* :c:func: `dsort`
* :c:func: `h_apply_cisd_diexc`
* :c:func: `h_apply_cisd_monoexc`
* :c:func: `make_s2_eigenfunction`
* :c:func: `wall_time`
Touches:
.. hlist ::
:columns: 3
* :c:data: `n_det`
* :c:data: `psi_occ_pattern`
* :c:data: `c0_weight`
* :c:data: `psi_coef`
* :c:data: `psi_det_sorted_bit`
* :c:data: `psi_det`
* :c:data: `psi_det_size`
* :c:data: `psi_det_sorted_bit`
* :c:data: `psi_occ_pattern`
.. c:function :: h_apply_cisd_diexc:
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File : :file: `h_apply.irp.f_shell_12`
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.. code :: fortran
subroutine H_apply_cisd_diexc(key_in, key_prev, hole_1,particl_1, hole_2, particl_2, fock_diag_tmp, i_generator, iproc_in )
Needs:
.. hlist ::
:columns: 3
* :c:data: `n_int`
* :c:data: `n_det`
* :c:data: `mo_num`
Called by:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd`
Calls:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_diexcp`
.. c:function :: h_apply_cisd_diexcorg:
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File : :file: `h_apply.irp.f_shell_12`
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.. code :: fortran
subroutine H_apply_cisd_diexcOrg(key_in,key_mask,hole_1,particl_1,hole_2, particl_2, fock_diag_tmp, i_generator, iproc_in )
Generate all double excitations of key_in using the bit masks of holes and
particles.
Assume N_int is already provided.
Needs:
.. hlist ::
:columns: 3
* :c:data: `n_int`
* :c:data: `elec_alpha_num`
* :c:data: `mo_num`
Called by:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_diexcp`
Calls:
.. hlist ::
:columns: 3
* :c:func: `bitstring_to_list_ab`
* :c:func: `fill_h_apply_buffer_no_selection`
.. c:function :: h_apply_cisd_diexcp:
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File : :file: `h_apply.irp.f_shell_12`
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.. code :: fortran
subroutine H_apply_cisd_diexcP(key_in, fs1, fh1, particl_1, fs2, fh2, particl_2, fock_diag_tmp, i_generator, iproc_in )
Needs:
.. hlist ::
:columns: 3
* :c:data: `n_int`
* :c:data: `n_det`
* :c:data: `mo_num`
Called by:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_diexc`
Calls:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_diexcorg`
.. c:function :: h_apply_cisd_monoexc:
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File : :file: `h_apply.irp.f_shell_12`
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.. code :: fortran
subroutine H_apply_cisd_monoexc(key_in, hole_1,particl_1,fock_diag_tmp,i_generator,iproc_in )
Generate all single excitations of key_in using the bit masks of holes and
particles.
Assume N_int is already provided.
Needs:
.. hlist ::
:columns: 3
* :c:data: `n_int`
* :c:data: `elec_alpha_num`
* :c:data: `mo_num`
Called by:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd`
Calls:
.. hlist ::
:columns: 3
* :c:func: `bitstring_to_list_ab`
* :c:func: `fill_h_apply_buffer_no_selection`
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.. c:function :: h_apply_cisd_sym:
File : :file: `h_apply.irp.f_shell_12`
.. code :: fortran
subroutine H_apply_cisd_sym()
Calls H_apply on the |HF| determinant and selects all connected single and double
excitations (of the same symmetry). Auto-generated by the `` generate_h_apply `` script.
Needs:
.. hlist ::
:columns: 3
* :c:data: `psi_coef`
* :c:data: `n_states`
* :c:data: `generators_bitmask`
* :c:data: `mo_num`
* :c:data: `mo_two_e_integrals_in_map`
* :c:data: `h_apply_buffer_allocated`
* :c:data: `n_det`
* :c:data: `s2_eig`
* :c:data: `n_det_generators`
* :c:data: `i_bitmask_gen`
* :c:data: `n_int`
* :c:data: `psi_det`
* :c:data: `psi_det_generators`
* :c:data: `psi_det_generators`
Calls:
.. hlist ::
:columns: 3
* :c:func: `build_fock_tmp`
* :c:func: `copy_h_apply_buffer_to_wf`
* :c:func: `dsort`
* :c:func: `h_apply_cisd_sym_diexc`
* :c:func: `h_apply_cisd_sym_monoexc`
* :c:func: `make_s2_eigenfunction`
* :c:func: `wall_time`
Touches:
.. hlist ::
:columns: 3
* :c:data: `n_det`
* :c:data: `psi_occ_pattern`
* :c:data: `c0_weight`
* :c:data: `psi_coef`
* :c:data: `psi_det_sorted_bit`
* :c:data: `psi_det`
* :c:data: `psi_det_size`
* :c:data: `psi_det_sorted_bit`
* :c:data: `psi_occ_pattern`
.. c:function :: h_apply_cisd_sym_diexc:
File : :file: `h_apply.irp.f_shell_12`
.. code :: fortran
subroutine H_apply_cisd_sym_diexc(key_in, key_prev, hole_1,particl_1, hole_2, particl_2, fock_diag_tmp, i_generator, iproc_in )
Needs:
.. hlist ::
:columns: 3
* :c:data: `n_int`
* :c:data: `n_det`
* :c:data: `mo_num`
Called by:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_sym`
Calls:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_sym_diexcp`
.. c:function :: h_apply_cisd_sym_diexcorg:
File : :file: `h_apply.irp.f_shell_12`
.. code :: fortran
subroutine H_apply_cisd_sym_diexcOrg(key_in,key_mask,hole_1,particl_1,hole_2, particl_2, fock_diag_tmp, i_generator, iproc_in )
Generate all double excitations of key_in using the bit masks of holes and
particles.
Assume N_int is already provided.
Needs:
.. hlist ::
:columns: 3
* :c:data: `n_int`
* :c:data: `elec_alpha_num`
* :c:data: `mo_num`
Called by:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_sym_diexcp`
Calls:
.. hlist ::
:columns: 3
* :c:func: `bitstring_to_list_ab`
* :c:func: `connected_to_hf`
* :c:func: `fill_h_apply_buffer_no_selection`
.. c:function :: h_apply_cisd_sym_diexcp:
File : :file: `h_apply.irp.f_shell_12`
.. code :: fortran
subroutine H_apply_cisd_sym_diexcP(key_in, fs1, fh1, particl_1, fs2, fh2, particl_2, fock_diag_tmp, i_generator, iproc_in )
Needs:
.. hlist ::
:columns: 3
* :c:data: `n_int`
* :c:data: `n_det`
* :c:data: `mo_num`
Called by:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_sym_diexc`
Calls:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_sym_diexcorg`
.. c:function :: h_apply_cisd_sym_monoexc:
File : :file: `h_apply.irp.f_shell_12`
.. code :: fortran
subroutine H_apply_cisd_sym_monoexc(key_in, hole_1,particl_1,fock_diag_tmp,i_generator,iproc_in )
Generate all single excitations of key_in using the bit masks of holes and
particles.
Assume N_int is already provided.
Needs:
.. hlist ::
:columns: 3
* :c:data: `n_int`
* :c:data: `elec_alpha_num`
* :c:data: `mo_num`
Called by:
.. hlist ::
:columns: 3
* :c:func: `h_apply_cisd_sym`
Calls:
.. hlist ::
:columns: 3
* :c:func: `bitstring_to_list_ab`
* :c:func: `connected_to_hf`
* :c:func: `fill_h_apply_buffer_no_selection`
