#!/usr/bin/env python
# Copyright 2014-2020 The PySCF Developers. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import numpy
from pyscf import lib
from pyscf.cc import rccsd
from pyscf.cc import uccsd
from pyscf.cc import gccsd
from pyscf.pbc import mp
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class RCCSD(rccsd.RCCSD):
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def ccsd(self, t1=None, t2=None, eris=None, mbpt2=False):
from pyscf.pbc.df.df_ao2mo import warn_pbc2d_eri
warn_pbc2d_eri(self._scf)
if mbpt2:
pt = mp.RMP2(self._scf, self.frozen, self.mo_coeff, self.mo_occ)
self.e_corr, self.t2 = pt.kernel(eris=eris)
nocc, nvir = self.t2.shape[1:3]
self.t1 = numpy.zeros((nocc,nvir))
return self.e_corr, self.t1, self.t2
return rccsd.RCCSD.ccsd(self, t1, t2, eris)
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def ao2mo(self, mo_coeff=None):
from pyscf.pbc import tools
ao2mofn = mp.mp2._gen_ao2mofn(self._scf)
# _scf.exxdiv affects eris.fock. HF exchange correction should be
# excluded from the Fock matrix.
with lib.temporary_env(self._scf, exxdiv=None):
eris = rccsd._make_eris_incore(self, mo_coeff, ao2mofn=ao2mofn)
# eris.mo_energy so far is just the diagonal part of the Fock matrix
# without the exxdiv treatment. Here to add the exchange correction to
# get better orbital energies. It is important for the low-dimension
# systems since their occupied and the virtual orbital energies may
# overlap which may lead to numerical issue in the CCSD iterations.
#if mo_coeff is self._scf.mo_coeff:
# eris.mo_energy = self._scf.mo_energy[self.get_frozen_mask()]
#else:
# Add the HFX correction of Ewald probe charge method.
# FIXME: Whether to add this correction for other exxdiv treatments?
# Without the correction, MP2 energy may be largely off the
# correct value.
madelung = tools.madelung(self._scf.cell, self._scf.kpt)
eris.mo_energy = _adjust_occ(eris.mo_energy, eris.nocc, -madelung)
return eris
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class UCCSD(uccsd.UCCSD):
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def ccsd(self, t1=None, t2=None, eris=None, mbpt2=False):
from pyscf.pbc.df.df_ao2mo import warn_pbc2d_eri
warn_pbc2d_eri(self._scf)
if mbpt2:
pt = mp.UMP2(self._scf, self.frozen, self.mo_coeff, self.mo_occ)
self.e_corr, self.t2 = pt.kernel(eris=eris)
nocca, noccb = self.nocc
nmoa, nmob = self.nmo
nvira, nvirb = nmoa-nocca, nmob-noccb
self.t1 = (numpy.zeros((nocca,nvira)), numpy.zeros((noccb,nvirb)))
return self.e_corr, self.t1, self.t2
return uccsd.UCCSD.ccsd(self, t1, t2, eris)
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def ao2mo(self, mo_coeff=None):
from pyscf.pbc import tools
ao2mofn = mp.mp2._gen_ao2mofn(self._scf)
# _scf.exxdiv affects eris.fock. HF exchange correction should be
# excluded from the Fock matrix.
with lib.temporary_env(self._scf, exxdiv=None):
eris = uccsd._make_eris_incore(self, mo_coeff, ao2mofn=ao2mofn)
#if mo_coeff is self._scf.mo_coeff:
# idxa, idxb = self.get_frozen_mask()
# mo_e_a, mo_e_b = self._scf.mo_energy
# eris.mo_energy = (mo_e_a[idxa], mo_e_b[idxb])
#else:
nocca, noccb = eris.nocc
madelung = tools.madelung(self._scf.cell, self._scf.kpt)
eris.mo_energy = (_adjust_occ(eris.mo_energy[0], nocca, -madelung),
_adjust_occ(eris.mo_energy[1], noccb, -madelung))
return eris
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class GCCSD(gccsd.GCCSD):
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def ccsd(self, t1=None, t2=None, eris=None, mbpt2=False):
from pyscf.pbc.df.df_ao2mo import warn_pbc2d_eri
warn_pbc2d_eri(self._scf)
if mbpt2:
from pyscf.pbc.mp import mp2
pt = mp2.GMP2(self._scf, self.frozen, self.mo_coeff, self.mo_occ)
self.e_corr, self.t2 = pt.kernel(eris=eris)
nocc, nvir = self.t2.shape[1:3]
self.t1 = numpy.zeros((nocc,nvir))
return self.e_corr, self.t1, self.t2
return gccsd.GCCSD.ccsd(self, t1, t2, eris)
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def ao2mo(self, mo_coeff=None):
from pyscf.pbc import tools
with_df = self._scf.with_df
kpt = self._scf.kpt
def ao2mofn(mo_coeff):
nao, nmo = mo_coeff.shape
mo_a = mo_coeff[:nao//2]
mo_b = mo_coeff[nao//2:]
orbspin = getattr(mo_coeff, 'orbspin', None)
if orbspin is None:
eri = with_df.ao2mo(mo_a, kpt, compact=False)
eri += with_df.ao2mo(mo_b, kpt, compact=False)
eri1 = with_df.ao2mo((mo_a,mo_a,mo_b,mo_b), kpt, compact=False)
eri += eri1
eri += eri1.T
eri = eri.reshape([nmo]*4)
else:
# If GHF orbitals have orbspin labels, alpha and beta orbitals
# occupy different columns. Here merging them into one set of
# orbitals then zero out spin forbidden MO integrals
mo = mo_a + mo_b
eri = with_df.ao2mo(mo, kpt, compact=False).reshape([nmo]*4)
sym_forbid = (orbspin[:,None] != orbspin)
eri[sym_forbid,:,:] = 0
eri[:,:,sym_forbid] = 0
return eri
# _scf.exxdiv affects eris.fock. HF exchange correction should be
# excluded from the Fock matrix.
with lib.temporary_env(self._scf, exxdiv=None):
eris = gccsd._make_eris_incore(self, mo_coeff, ao2mofn=ao2mofn)
#if mo_coeff is self._scf.mo_coeff:
# eris.mo_energy = self._scf.mo_energy[self.get_frozen_mask()]
#else:
madelung = tools.madelung(self._scf.cell, self._scf.kpt)
eris.mo_energy = _adjust_occ(eris.mo_energy, eris.nocc, -madelung)
return eris
def _adjust_occ(mo_energy, nocc, shift):
'''Modify occupied orbital energy'''
mo_energy = mo_energy.copy()
mo_energy[:nocc] += shift
return mo_energy
from pyscf.pbc import scf
scf.hf.RHF.CCSD = lib.class_as_method(RCCSD)
scf.uhf.UHF.CCSD = lib.class_as_method(UCCSD)
scf.ghf.GHF.CCSD = lib.class_as_method(GCCSD)
scf.rohf.ROHF.CCSD = None