1# Copyright 2014-2020 The PySCF Developers. All Rights Reserved.
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15'''
16Density functional theory
17=========================
18
19Simple usage::
20
21    >>> from pyscf import gto, dft
22    >>> mol = gto.M(atom='N 0 0 0; N 0 0 1', basis='def2-tzvp')
23    >>> mf = dft.RKS(mol)
24    >>> mf.xc = 'pbe,pbe'
25    >>> mf.run()
26'''
27
28try:
29    from pyscf.dft import libxc
30    XC = libxc.XC
31except (ImportError, OSError):
32    pass
33try:
34    from pyscf.dft import xcfun
35    XC = xcfun.XC
36except (ImportError, OSError):
37    pass
38#from pyscf.dft import xc
39from pyscf.dft import rks
40from pyscf.dft import roks
41from pyscf.dft import uks
42from pyscf.dft import gks
43from pyscf.dft import rks_symm
44from pyscf.dft import uks_symm
45from pyscf.dft import gks_symm
46from pyscf.dft import dks
47from pyscf.dft import gen_grid as grid
48from pyscf.dft import radi
49from pyscf.dft import numint
50from pyscf.df import density_fit
51from pyscf.dft.gen_grid import sg1_prune, nwchem_prune, treutler_prune, \
52        stratmann, original_becke, Grids
53from pyscf.dft.radi import BRAGG_RADII, COVALENT_RADII, \
54        delley, mura_knowles, gauss_chebyshev, treutler, treutler_ahlrichs, \
55        treutler_atomic_radii_adjust, becke_atomic_radii_adjust
56
57
58def KS(mol, xc='LDA,VWN'):
59    if mol.spin == 0:
60        return RKS(mol, xc)
61    else:
62        return UKS(mol, xc)
63KS.__doc__ = '''
64A wrap function to create DFT object (RKS or UKS).\n
65''' + rks.RKS.__doc__
66DFT = KS
67
68def RKS(mol, xc='LDA,VWN'):
69    if mol.nelectron == 1:
70        return uks.UKS(mol)
71    elif not mol.symmetry or mol.groupname == 'C1':
72        if mol.spin > 0:
73            return roks.ROKS(mol, xc)
74        else:
75            return rks.RKS(mol, xc)
76    else:
77        if mol.spin > 0:
78            return rks_symm.ROKS(mol, xc)
79        else:
80            return rks_symm.RKS(mol, xc)
81RKS.__doc__ = rks.RKS.__doc__
82
83def ROKS(mol, xc='LDA,VWN'):
84    if mol.nelectron == 1:
85        return uks.UKS(mol)
86    elif not mol.symmetry or mol.groupname == 'C1':
87        return roks.ROKS(mol, xc)
88    else:
89        return rks_symm.ROKS(mol, xc)
90ROKS.__doc__ = roks.ROKS.__doc__
91
92def UKS(mol, xc='LDA,VWN'):
93    if not mol.symmetry or mol.groupname == 'C1':
94        return uks.UKS(mol, xc)
95    else:
96        return uks_symm.UKS(mol, xc)
97UKS.__doc__ = uks.UKS.__doc__
98
99def GKS(mol, xc='LDA,VWN'):
100    if not mol.symmetry or mol.groupname == 'C1':
101        return gks.GKS(mol, xc)
102    else:
103        return gks_symm.GKS(mol, xc)
104GKS.__doc__ = gks.GKS.__doc__
105
106def DKS(mol, xc='LDA,VWN'):
107    from pyscf.scf import dhf
108    if dhf.zquatev and mol.spin == 0:
109        return dks.RDKS(mol, xc=xc)
110    else:
111        return dks.UDKS(mol, xc=xc)
112