1#!/usr/bin/env python 2# Copyright 2014-2020 The PySCF Developers. All Rights Reserved. 3# 4# Licensed under the Apache License, Version 2.0 (the "License"); 5# you may not use this file except in compliance with the License. 6# You may obtain a copy of the License at 7# 8# http://www.apache.org/licenses/LICENSE-2.0 9# 10# Unless required by applicable law or agreed to in writing, software 11# distributed under the License is distributed on an "AS IS" BASIS, 12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13# See the License for the specific language governing permissions and 14# limitations under the License. 15# 16# Author: Qiming Sun <osirpt.sun@gmail.com> 17 18''' 19Density fitting 20=============== 21 22This module provides the fundamental functions to handle the 3-index tensors 23(including the 3-center 2-electron AO and MO integrals, the Cholesky 24decomposed integrals) required by the density fitting method or the RI 25(resolution of identity) approximation. 26 27Simple usage:: 28 29 >>> from pyscf import gto, dft 30 >>> mol = gto.M(atom='N 0 0 0; N 0 0 1', basis='ccpvdz') 31 >>> mf = dft.RKS(mol).density_fit().run() 32''' 33 34from . import incore 35from . import outcore 36from . import addons 37from .addons import load, aug_etb, DEFAULT_AUXBASIS, make_auxbasis, make_auxmol 38from .df import DF, GDF, DF4C, GDF4C 39 40from . import r_incore 41 42def density_fit(obj, *args, **kwargs): 43 '''Given SCF/MCSCF or post-HF object, use density fitting technique to 44 approximate the 2e integrals.''' 45 return obj.density_fit(*args, **kwargs) 46 47