.. index:: single: Program; CPF single: CPF .. _UG\:sec\:cpf: :program:`cpf` ============== .. only:: html .. contents:: :local: :backlinks: none Description ----------- .. xmldoc:: %%Description: This program performs standard SDCI calculations, or CPF calculations as described by Ahlrichs; MCPF calculations(Chong) or ACPF calculations(Gdanitz). In each case, the reference is normally a single determinant, possibly with a few high-spin coupled open shells, but low-spin cases are also possible. It was originally written by Siegbahn and Blomberg, and has only been slightly modified to fit MOLCAS. It requires a file generated by the GUGA program. See manual. The :program:`CPF` program generates :index:`SDCI `, :index:`CPF` :cite:`Ahlrichs:85`, :index:`MCPF` :cite:`Chong:86` or :index:`ACPF ` :cite:`Gdanitz:88`, wavefunctions from **one** reference configuration. The :program:`CPF` program is a modification to a CPF program written by P. E. M. Siegbahn and M. Blomberg (Institute of Physics, Stockholm University, Sweden). The program is based on the Direct CI method :cite:`Roos:72`, with the coupling coefficients generated by the Graphical Unitary Group Approach :cite:`Shavitt:77,Shavitt:78,Siegbahn:80` (See program description for :program:`GUGA`). :program:`CPF` generates natural orbitals that can be fed into the property program to evaluate certain one electron properties. Also, the natural orbitals can be used for Iterative Natural Orbital calculations. Orbital subspaces ----------------- The orbital space is divided into the following subspaces: :index:`Frozen `, :index:`Inactive `, :index:`Active `, :index:`Secondary `, and :index:`Deleted ` orbitals. Within each symmetry type, they follow this order. Their meaning is the same as explained in the :program:`GUGA` and :program:`MOTRA` sections, except that, in this case, there is only a single reference configuration. Therefore, the active orbitals in this case are usually only open shells, if any. Since explicit handling of orbitals is taken care of at the integral transformation step, program :program:`MOTRA`, orbital spaces are not specified in the input, except when orbitals are frozen or deleted by the :program:`CPF` program, rather than by :program:`MOTRA` (which should normally be avoided). .. index:: pair: Dependencies; CPF .. _UG\:sec\:cpf_dependencies: Dependencies ------------ The :program:`CPF` program needs the coupling coefficients generated by the program :program:`GUGA` and the transformed one and two electron integrals from the program :program:`MOTRA`. .. index:: pair: Files; CPF .. _UG\:sec\:cpf_files: Files ----- Input files ........... The :program:`CPF` program need the coupling coefficients generated by :program:`GUGA` and the transformed integrals from :program:`MOTRA`. :program:`CPF` will use the following input files: :file:`ONEINT`, :file:`RUNFILE`, :file:`CIGUGA`, :file:`TRAINT`, :file:`TRAONE` (for more information see :numref:`UG:sec:files_list`). and :file:`CPFVECT` (for restarted calculations). Output files ............ :program:`CPF` generates an two output files: .. class:: filelist :file:`CPFORB` The natural orbitals from the CPF functional. :file:`CPFVECT` The CI expansion coefficients. These may be used for restarting an unconverged calculation. .. index:: pair: Input; CPF .. _UG\:sec\:cpf_input: Input ----- This section describes the input to the :program:`CPF` program in the |molcas| program system. The input for each module is preceded by its name like: :: &CPF .. index:: pair: Keywords; CPF Optional keywords ................. .. class:: keywordlist :kword:`TITLe` Followed by a title line .. xmldoc:: %%Keyword: Title Followed by a title line :kword:`SDCI` Specifies that a SDCI calculation is to be performed. No additional input is required. Only one of the choices SDCI, CPF, MCPF or ACPF should be chosen. .. xmldoc:: :kword:`RESTart` Restart the calculation from a previous calculation. .. xmldoc:: %%Keyword: Restart Restart the calculation from a previous calculation. :kword:`THRPr` Threshold for printout of the wavefunction. All configurations with a coefficient greater than this threshold are printed in the final printout. The default is 0.05. .. xmldoc:: %%Keyword: ThrPrint Set threshold on CI coefficients to be printed. Default 0.05. :kword:`ECONvergence` Energy convergence threshold. The update procedure is repeated until the energy difference between the last two iterations is less than this threshold. The default is 1.0e-8. .. xmldoc:: %%Keyword: EConvergence Set energy threshold for convergence. Default 1.0D-8. :kword:`PRINt` Print level of the program. Default is 5. .. xmldoc:: %%Keyword: PrintLevel Set print level. Default is 5. :kword:`MAXIterations` Maximum number of iterations in the update procedure. Default 20. The maximum value of this parameter is 75. .. xmldoc:: %%Keyword: MaxIterations Set maximum iterations. Default 20, max possible 75. :kword:`FROZen` Specify the number of orbitals to be frozen in **addition** to the orbitals frozen in the integral transformation. Default is 0 in all symmetries. .. xmldoc:: %%Keyword: Frozen Specify, for each symmetry, how many orbitals to keep uncorrelated in addition to any that were frozen already by MOTRA. :kword:`DELEted` Specify the number of orbitals to be deleted in **addition** to the orbitals deleted in the integral transformation. Default is 0 in all symmetries. .. xmldoc:: %%Keyword: Deleted Specify, for each symmetry, how many orbitals to delete in addition to any that were deleted already by MOTRA. :kword:`LOW` Specifies that this is a low spin case, i.e. the spin is less than the maximum possible with the number of open shells in the calculation. See Refs. :cite:`Ahlrichs:85,Chong:86`. This requires special considerations. .. xmldoc:: %%Keyword: Low Specifies a low spin case, see manual. :kword:`MAXPulay` Maximum number of iterations in the initial stage. After that, DIIS extrapolation will be used. Default is 6. .. xmldoc:: %%Keyword: MaxPulay Number of iterations until DIIS extrapolation is switched on. :kword:`LEVShift` Levelshift in the update procedure. Default is 0.3. .. xmldoc:: %%Keyword: LevShift Enter level shift to use in the equation solver. Default is 0.3. Input example ............. :: &CPF Title Water molecule. 1S frozen in transformation. MCPF .. xmldoc::