forte2.integrals.libcint_utils
==============================

.. py:module:: forte2.integrals.libcint_utils






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

.. py:data:: c_double_p

.. py:data:: c_int_p

.. py:data:: c_null_ptr

.. py:data:: PLAIN
   :value: 0


.. py:data:: HERMITIAN
   :value: 1


.. py:data:: ANTIHERMI
   :value: 2


.. py:data:: SYMMETRIC
   :value: 3


.. py:data:: CHARGE_OF
   :value: 0


.. py:data:: PTR_COORD
   :value: 1


.. py:data:: NUC_MOD_OF
   :value: 2


.. py:data:: PTR_ZETA
   :value: 3


.. py:data:: PTR_FRAC_CHARGE
   :value: 4


.. py:data:: PTR_RADIUS
   :value: 5


.. py:data:: ATM_SLOTS
   :value: 6


.. py:data:: ATOM_OF
   :value: 0


.. py:data:: ANG_OF
   :value: 1


.. py:data:: NPRIM_OF
   :value: 2


.. py:data:: NCTR_OF
   :value: 3


.. py:data:: RADI_POWER
   :value: 3


.. py:data:: KAPPA_OF
   :value: 4


.. py:data:: SO_TYPE_OF
   :value: 4


.. py:data:: PTR_EXP
   :value: 5


.. py:data:: PTR_COEFF
   :value: 6


.. py:data:: BAS_SLOTS
   :value: 8


.. py:data:: PTR_EXPCUTOFF
   :value: 0


.. py:data:: PTR_COMMON_ORIG
   :value: 1


.. py:data:: PTR_RINV_ORIG
   :value: 4


.. py:data:: PTR_RINV_ZETA
   :value: 7


.. py:data:: PTR_RANGE_OMEGA
   :value: 8


.. py:data:: PTR_F12_ZETA
   :value: 9


.. py:data:: PTR_GTG_ZETA
   :value: 10


.. py:data:: NGRIDS
   :value: 11


.. py:data:: PTR_GRIDS
   :value: 12


.. py:data:: AS_RINV_ORIG_ATOM
   :value: 17


.. py:data:: AS_ECPBAS_OFFSET
   :value: 18


.. py:data:: AS_NECPBAS
   :value: 19


.. py:data:: PTR_ENV_START
   :value: 20


.. py:data:: NUC_POINT
   :value: 1


.. py:data:: NUC_GAUSS
   :value: 2


.. py:data:: NUC_FRAC_CHARGE
   :value: 3


.. py:data:: NUC_ECP
   :value: 4


.. py:data:: NORMALIZE_GTO
   :value: True


.. py:function:: make_env(atoms, basis, pre_env=[], nucmod={})

   
   Generate the input arguments for ``libcint`` library based on internal
   format :attr:`Mole._atom` and :attr:`Mole._basis`
















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.. py:function:: make_atm_env(atom, ptr=0, nuclear_model=NUC_POINT, nucprop={})

   
   Convert the internal format :attr:`Mole._atom` to the format required
   by ``libcint`` integrals
















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.. py:function:: make_bas_env(basis_add, atom_id=0, ptr=0)

   
   Convert :attr:`Mole.basis` to the argument ``bas`` for ``libcint`` integrals
















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.. py:function:: gaussian_int(n, alpha)

   
   int_0^inf x^n exp(-alpha x^2) dx
















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.. py:function:: dyall_nuc_mod(nuc_charge, nucprop={})

   
   Generate the nuclear charge distribution parameter zeta
   rho(r) = nuc_charge * Norm * exp(-zeta * r^2)

   Ref. L. Visscher and K. Dyall, At. Data Nucl. Data Tables, 67, 207 (1997)















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.. py:function:: gto_norm(l, expnt)

   
   Normalized factor for GTO radial part   :math:`g=r^l e^{-\alpha r^2}`

   .. math::

       \frac{1}{\sqrt{\int g^2 r^2 dr}}
       = \sqrt{\frac{2^{2l+3} (l+1)! (2a)^{l+1.5}}{(2l+2)!\sqrt{\pi}}}

   Ref: H. B. Schlegel and M. J. Frisch, Int. J. Quant.  Chem., 54(1995), 83-87.

   Args:
       l (int):
           angular momentum
       expnt :
           exponent :math:`\alpha`

   Returns:
       normalization factor

   Examples:

   >>> print(gto_norm(0, 1))
   2.5264751109842591















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.. py:function:: len_spinor(l, kappa)

   
   The number of spinor associated with given angular momentum and kappa.  If kappa is 0,
   return 4l+2
















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.. py:function:: flatten(lst)

   
   flatten nested lists
   x[0] + x[1] + x[2] + ...

   Examples:

   >>> flatten([[0, 2], [1], [[9, 8, 7]]])
   [0, 2, 1, [9, 8, 7]]















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.. py:function:: conc_env(atm1, bas1, env1, atm2, bas2, env2)

   
   Concatenate two sets of libcint input arguments for cross integrals
















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.. py:function:: basis_to_cint_envs(system, basis, common_origin=None)

   
   Convert a Forte2 Basis object to libcint atm, bas, env objects.


   :Parameters:

       **system** : forte2.System
           The system object containing the geometry and basis set.

       **basis** : forte2.Basis
           The basis object to be converted.














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