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class.irp.f | ||
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fci.irp.f | ||
NEED | ||
pt2.irp.f | ||
README.rst | ||
save_energy.irp.f |
=== fci === |CIPSI| algorithm in the full configuration interaction space. The user point of view ---------------------- * :ref:`fci` performs |CIPSI| calculations using a stochastic scheme for both the selection and the |PT2| contribution, * :ref:`pt2` computes the |PT2| contribution using the wave function stored in the |EZFIO| database. The main keywords/options for this module are: * :option:`determinants n_det_max` : maximum number of Slater determinants in the |CIPSI| wave function. The :ref:`fci` program will stop when the size of the |CIPSI| wave function will exceed :option:`determinants n_det_max`. * :option:`perturbation pt2_max` : absolute value of the |PT2| to stop the |CIPSI| calculation. Once the abs(|PT2|) :math:`<` :option:`perturbation pt2_max`, the |CIPSI| calculation stops. * :option:`determinants n_states` : number of states to consider in the |CIPSI| calculation. * :option:`determinants read_wf` : if |false|, starts with a |ROHF|-like determinant, if |true|, starts with the current wave function(s) stored in the |EZFIO| directory. .. note:: For a multi-state calculation, it is recommended to start with :ref:`cis` or :ref:`cisd` wave functions as a guess. * :option:`determinants expected_s2` : expected value of |S^2| for the desired spin multiplicity. * :option:`determinants s2_eig` : if |true|, systematically add all the determinants needed to have a pure value of |S^2|. Also, if |true|, it tracks only the states having the good :option:`determinants expected_s2`. The programmer's point of view ------------------------------ This module was created with the :ref:`module_cipsi` module. .. seealso:: The documentation of the :ref:`module_cipsi` module.