#!/usr/bin/env python
# Copyright 2014-2021 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.
#
# Author: Qiming Sun <osirpt.sun@gmail.com>
#
'''
General spin-orbital CISD
'''
import warnings
from functools import reduce
import numpy
from pyscf import lib
from pyscf.lib import logger
from pyscf.cc import ccsd
from pyscf.cc import gccsd
from pyscf.cc import gccsd_rdm
from pyscf.cc.addons import spatial2spin, spin2spatial
from pyscf.ci import cisd
from pyscf.ci import ucisd
[docs]
def make_diagonal(myci, eris):
nocc = myci.nocc
nmo = myci.nmo
nvir = nmo - nocc
mo_energy = eris.fock.diagonal()
jkdiag = numpy.zeros((nmo,nmo), dtype=mo_energy.dtype)
jkdiag[:nocc,:nocc] = numpy.einsum('ijij->ij', eris.oooo)
jkdiag[nocc:,nocc:] = numpy.einsum('ijij->ij', eris.vvvv)
jkdiag[:nocc,nocc:] = numpy.einsum('ijij->ij', eris.ovov)
jksum = jkdiag[:nocc,:nocc].sum()
ehf = mo_energy[:nocc].sum() - jksum * .5
e1diag = numpy.empty((nocc,nvir), dtype=mo_energy.dtype)
e2diag = numpy.empty((nocc,nocc,nvir,nvir), dtype=mo_energy.dtype)
for i in range(nocc):
for a in range(nocc, nmo):
e1diag[i,a-nocc] = ehf - mo_energy[i] + mo_energy[a] - jkdiag[i,a]
for j in range(nocc):
for b in range(nocc, nmo):
e2diag[i,j,a-nocc,b-nocc] = ehf \
- mo_energy[i] - mo_energy[j] \
+ mo_energy[a] + mo_energy[b] \
+ jkdiag[i,j] + jkdiag[a,b] \
- jkdiag[i,a] - jkdiag[j,a] \
- jkdiag[i,b] - jkdiag[j,b]
return amplitudes_to_cisdvec(ehf, e1diag, e2diag)
[docs]
def contract(myci, civec, eris):
nocc = myci.nocc
nmo = myci.nmo
c0, c1, c2 = cisdvec_to_amplitudes(civec, nmo, nocc, copy=False)
fock = eris.fock
foo = fock[:nocc,:nocc]
fov = fock[:nocc,nocc:]
fvo = fock[nocc:,:nocc]
fvv = fock[nocc:,nocc:]
t1 = lib.einsum('ie,ae->ia', c1, fvv)
t1 -= lib.einsum('ma,mi->ia', c1, foo)
t1 += lib.einsum('imae,me->ia', c2, fov)
t1 += lib.einsum('nf,nafi->ia', c1, eris.ovvo)
t1 -= 0.5*lib.einsum('imef,maef->ia', c2, eris.ovvv)
t1 -= 0.5*lib.einsum('mnae,mnie->ia', c2, eris.ooov)
tmp = lib.einsum('ijae,be->ijab', c2, fvv)
t2 = tmp - tmp.transpose(0,1,3,2)
tmp = lib.einsum('imab,mj->ijab', c2, foo)
t2 -= tmp - tmp.transpose(1,0,2,3)
t2 += 0.5*lib.einsum('mnab,mnij->ijab', c2, eris.oooo)
t2 += 0.5*lib.einsum('ijef,abef->ijab', c2, eris.vvvv)
tmp = lib.einsum('imae,mbej->ijab', c2, eris.ovvo)
tmp+= numpy.einsum('ia,bj->ijab', c1, fvo)
tmp = tmp - tmp.transpose(0,1,3,2)
t2 += tmp - tmp.transpose(1,0,2,3)
tmp = lib.einsum('ie,jeba->ijab', c1, numpy.asarray(eris.ovvv).conj())
t2 += tmp - tmp.transpose(1,0,2,3)
tmp = lib.einsum('ma,ijmb->ijab', c1, numpy.asarray(eris.ooov).conj())
t2 -= tmp - tmp.transpose(0,1,3,2)
eris_oovv = numpy.asarray(eris.oovv)
t1 += fov.conj() * c0
t2 += eris_oovv.conj() * c0
t0 = numpy.einsum('ia,ia', fov, c1)
t0 += numpy.einsum('ijab,ijab', eris_oovv, c2) * .25
return amplitudes_to_cisdvec(t0, t1, t2)
[docs]
def amplitudes_to_cisdvec(c0, c1, c2):
nocc, nvir = c1.shape
ooidx = numpy.tril_indices(nocc, -1)
vvidx = numpy.tril_indices(nvir, -1)
c2tril = lib.take_2d(c2.reshape(nocc**2,nvir**2),
ooidx[0]*nocc+ooidx[1], vvidx[0]*nvir+vvidx[1])
return numpy.hstack((c0, c1.ravel(), c2tril.ravel()))
[docs]
def cisdvec_to_amplitudes(civec, nmo, nocc, copy=True):
nvir = nmo - nocc
c0 = civec[0]
cp = lambda x: (x.copy() if copy else x)
c1 = cp(civec[1:nocc*nvir+1].reshape(nocc,nvir))
c2 = ccsd._unpack_4fold(civec[nocc*nvir+1:], nocc, nvir)
return c0, c1, c2
[docs]
def from_ucisdvec(civec, nocc, orbspin):
'''Convert the (spin-separated) CISD coefficient vector to GCISD
coefficient vector'''
nmoa = numpy.count_nonzero(orbspin == 0)
nmob = numpy.count_nonzero(orbspin == 1)
if isinstance(nocc, int):
nocca = numpy.count_nonzero(orbspin[:nocc] == 0)
noccb = numpy.count_nonzero(orbspin[:nocc] == 1)
else:
nocca, noccb = nocc
nvira = nmoa - nocca
if civec.size == nocca*nvira + (nocca*nvira)**2 + 1: # RCISD
c0, c1, c2 = cisd.cisdvec_to_amplitudes(civec, nmoa, nocca, copy=False)
else: # UCISD
c0, c1, c2 = ucisd.cisdvec_to_amplitudes(civec, (nmoa,nmob), (nocca,noccb), copy=False)
c1 = spatial2spin(c1, orbspin)
c2 = spatial2spin(c2, orbspin)
return amplitudes_to_cisdvec(c0, c1, c2)
from_rcisdvec = from_ucisdvec
[docs]
def to_ucisdvec(civec, nmo, nocc, orbspin):
'''Convert the GCISD coefficient vector to UCISD coefficient vector'''
c0, c1, c2 = cisdvec_to_amplitudes(civec, nmo, nocc, copy=False)
c1 = spin2spatial(c1, orbspin)
c2 = spin2spatial(c2, orbspin)
ucisdvec = ucisd.amplitudes_to_cisdvec(c0, c1, c2)
unorm = numpy.linalg.norm(ucisdvec)
if unorm < 1e-2:
raise RuntimeError('GCISD vector corresponds to spin-flip excitation. '
'It cannot be converted to UCISD wfn.'
'norm(UCISD) = %s' % unorm)
elif unorm < 0.99:
warnings.warn('GCISD vector has spin-flip excitation. '
'They are ignored when converting to UCISD wfn. '
'norm(UCISD) = %s' % unorm)
return ucisdvec
[docs]
def to_fcivec(cisdvec, nelec, orbspin, frozen=None):
assert (numpy.count_nonzero(orbspin == 0) ==
numpy.count_nonzero(orbspin == 1))
norb = len(orbspin)
frozen_mask = numpy.zeros(norb, dtype=bool)
if frozen is None:
pass
elif isinstance(frozen, (int, numpy.integer)):
frozen_mask[:frozen] = True
else:
frozen_mask[frozen] = True
frozen = (numpy.where(frozen_mask[orbspin == 0])[0],
numpy.where(frozen_mask[orbspin == 1])[0])
nelec = (numpy.count_nonzero(orbspin[:nelec] == 0),
numpy.count_nonzero(orbspin[:nelec] == 1))
orbspin = orbspin[~frozen_mask]
nmo = len(orbspin)
nocc = numpy.count_nonzero(~frozen_mask[:sum(nelec)])
ucisdvec = to_ucisdvec(cisdvec, nmo, nocc, orbspin)
return ucisd.to_fcivec(ucisdvec, norb//2, nelec, frozen)
[docs]
def from_fcivec(ci0, nelec, orbspin, frozen=None):
if not (frozen is None or frozen == 0):
raise NotImplementedError
assert (numpy.count_nonzero(orbspin == 0) ==
numpy.count_nonzero(orbspin == 1))
norb = len(orbspin)
frozen_mask = numpy.zeros(norb, dtype=bool)
if frozen is None:
pass
elif isinstance(frozen, (int, numpy.integer)):
frozen_mask[:frozen] = True
else:
frozen_mask[frozen] = True
#frozen = (numpy.where(frozen_mask[orbspin == 0])[0],
# numpy.where(frozen_mask[orbspin == 1])[0])
nelec = (numpy.count_nonzero(orbspin[:nelec] == 0),
numpy.count_nonzero(orbspin[:nelec] == 1))
ucisdvec = ucisd.from_fcivec(ci0, norb//2, nelec, frozen)
nocc = numpy.count_nonzero(~frozen_mask[:sum(nelec)])
return from_ucisdvec(ucisdvec, nocc, orbspin[~frozen_mask])
[docs]
def make_rdm1(myci, civec=None, nmo=None, nocc=None, ao_repr=False):
r'''
One-particle density matrix in the molecular spin-orbital representation
(the occupied-virtual blocks from the orbital response contribution are
not included).
dm1[p,q] = <q^\dagger p> (p,q are spin-orbitals)
The convention of 1-pdm is based on McWeeney's book, Eq (5.4.20).
The contraction between 1-particle Hamiltonian and rdm1 is
E = einsum('pq,qp', h1, rdm1)
'''
if civec is None: civec = myci.ci
if nmo is None: nmo = myci.nmo
if nocc is None: nocc = myci.nocc
d1 = _gamma1_intermediates(myci, civec, nmo, nocc)
return gccsd_rdm._make_rdm1(myci, d1, with_frozen=True, ao_repr=ao_repr)
[docs]
def make_rdm2(myci, civec=None, nmo=None, nocc=None, ao_repr=False):
r'''
Two-particle density matrix in the molecular spin-orbital representation
dm2[p,q,r,s] = <p^\dagger r^\dagger s q>
where p,q,r,s are spin-orbitals. p,q correspond to one particle and r,s
correspond to another particle. The contraction between ERIs (in
Chemist's notation) and rdm2 is
E = einsum('pqrs,pqrs', eri, rdm2)
'''
if civec is None: civec = myci.ci
if nmo is None: nmo = myci.nmo
if nocc is None: nocc = myci.nocc
d1 = _gamma1_intermediates(myci, civec, nmo, nocc)
d2 = _gamma2_intermediates(myci, civec, nmo, nocc)
return gccsd_rdm._make_rdm2(myci, d1, d2, with_dm1=True, with_frozen=True,
ao_repr=ao_repr)
def _gamma1_intermediates(myci, civec, nmo, nocc):
c0, c1, c2 = cisdvec_to_amplitudes(civec, nmo, nocc, copy=False)
dvo = c0.conj() * c1.T
dvo += numpy.einsum('jb,ijab->ai', c1.conj(), c2)
dov = dvo.T.conj()
doo =-numpy.einsum('ia,ka->ik', c1.conj(), c1)
doo -= numpy.einsum('jiab,kiab->jk', c2.conj(), c2) * .5
dvv = numpy.einsum('ia,ic->ac', c1, c1.conj())
dvv += numpy.einsum('ijab,ijac->bc', c2, c2.conj()) * .5
return doo, dov, dvo, dvv
def _gamma2_intermediates(myci, civec, nmo, nocc):
c0, c1, c2 = cisdvec_to_amplitudes(civec, nmo, nocc, copy=False)
goovv = c0 * c2.conj() * .5
govvv = numpy.einsum('ia,ikcd->kadc', c1, c2.conj()) * .5
gooov = numpy.einsum('ia,klac->klic', c1, c2.conj()) *-.5
goooo = numpy.einsum('ijab,klab->ijkl', c2.conj(), c2) * .25
gvvvv = numpy.einsum('ijab,ijcd->abcd', c2, c2.conj()) * .25
govvo = numpy.einsum('ijab,ikac->jcbk', c2.conj(), c2)
govvo+= numpy.einsum('ia,jb->ibaj', c1.conj(), c1)
dovov = goovv.transpose(0,2,1,3) - goovv.transpose(0,3,1,2)
doooo = goooo.transpose(0,2,1,3) - goooo.transpose(0,3,1,2)
dvvvv = gvvvv.transpose(0,2,1,3) - gvvvv.transpose(0,3,1,2)
dovvo = govvo.transpose(0,2,1,3)
dooov = gooov.transpose(0,2,1,3) - gooov.transpose(1,2,0,3)
dovvv = govvv.transpose(0,2,1,3) - govvv.transpose(0,3,1,2)
doovv = None
dvvov = None
return dovov, dvvvv, doooo, doovv, dovvo, dvvov, dovvv, dooov
[docs]
def trans_rdm1(myci, cibra, ciket, nmo=None, nocc=None):
r'''
One-particle transition density matrix in the molecular spin-orbital
representation.
dm1[p,q] = <q^\dagger p> (p,q are spin-orbitals)
The convention of 1-pdm is based on McWeeney's book, Eq (5.4.20).
The contraction between 1-particle Hamiltonian and rdm1 is
E = einsum('pq,qp', h1, rdm1)
'''
if nmo is None: nmo = myci.nmo
if nocc is None: nocc = myci.nocc
c0bra, c1bra, c2bra = myci.cisdvec_to_amplitudes(cibra, nmo, nocc, copy=False)
c0ket, c1ket, c2ket = myci.cisdvec_to_amplitudes(ciket, nmo, nocc, copy=False)
dvo = c0bra.conj() * c1ket.T
dvo += numpy.einsum('jb,ijab->ai', c1bra.conj(), c2ket)
dov = c0ket * c1bra.conj()
dov += numpy.einsum('jb,ijab->ia', c1ket, c2bra.conj())
doo =-numpy.einsum('ia,ka->ik', c1bra.conj(), c1ket)
doo -= numpy.einsum('jiab,kiab->jk', c2bra.conj(), c2ket) * .5
dvv = numpy.einsum('ia,ic->ac', c1ket, c1bra.conj())
dvv += numpy.einsum('ijab,ijac->bc', c2ket, c2bra.conj()) * .5
dm1 = numpy.empty((nmo,nmo), dtype=doo.dtype)
dm1[:nocc,:nocc] = doo
dm1[:nocc,nocc:] = dov
dm1[nocc:,:nocc] = dvo
dm1[nocc:,nocc:] = dvv
norm = numpy.dot(cibra, ciket)
dm1[numpy.diag_indices(nocc)] += norm
if myci.frozen is not None:
nmo = myci.mo_occ.size
nocc = numpy.count_nonzero(myci.mo_occ > 0)
rdm1 = numpy.zeros((nmo,nmo), dtype=dm1.dtype)
rdm1[numpy.diag_indices(nocc)] = norm
moidx = numpy.where(myci.get_frozen_mask())[0]
rdm1[moidx[:,None],moidx] = dm1
dm1 = rdm1
return dm1
[docs]
class GCISD(cisd.CISD):
[docs]
def vector_size(self):
nocc = self.nocc
nvir = self.nmo - nocc
noo = nocc * (nocc-1) // 2
nvv = nvir * (nvir-1) // 2
return 1 + nocc*nvir + noo*nvv
[docs]
def get_init_guess(self, eris=None, nroots=1, diag=None):
# MP2 initial guess
if eris is None: eris = self.ao2mo(self.mo_coeff)
time0 = logger.process_clock(), logger.perf_counter()
mo_e = eris.mo_energy
nocc = self.nocc
eia = mo_e[:nocc,None] - mo_e[None,nocc:]
eijab = lib.direct_sum('ia,jb->ijab',eia,eia)
ci0 = 1
ci1 = eris.fock[:nocc,nocc:] / eia
eris_oovv = numpy.array(eris.oovv)
ci2 = eris_oovv / eijab
self.emp2 = 0.25*numpy.einsum('ijab,ijab', ci2.conj(), eris_oovv).real
logger.info(self, 'Init t2, MP2 energy = %.15g', self.emp2)
logger.timer(self, 'init mp2', *time0)
if abs(self.emp2) < 1e-3 and abs(ci1).sum() < 1e-3:
ci1 = 1. / eia
ci_guess = amplitudes_to_cisdvec(ci0, ci1, ci2)
if nroots > 1:
civec_size = ci_guess.size
dtype = ci_guess.dtype
nroots = min(ci1.size+1, nroots) # Consider Koopmans' theorem only
if diag is None:
idx = range(1, nroots)
else:
idx = diag[:ci1.size+1].argsort()[1:nroots] # exclude HF determinant
ci_guess = [ci_guess]
for i in idx:
g = numpy.zeros(civec_size, dtype)
g[i] = 1.0
ci_guess.append(g)
return self.emp2, ci_guess
[docs]
def ao2mo(self, mo_coeff=None):
nmo = self.nmo
mem_incore = nmo**4*2 * 8/1e6
mem_now = lib.current_memory()[0]
if (self._scf._eri is not None and
(mem_incore+mem_now < self.max_memory) or self.mol.incore_anyway):
return gccsd._make_eris_incore(self, mo_coeff)
elif getattr(self._scf, 'with_df', None):
raise NotImplementedError
else:
return gccsd._make_eris_outcore(self, mo_coeff)
contract = contract
make_diagonal = make_diagonal
_dot = None
[docs]
def to_fcivec(self, cisdvec, nelec, orbspin, frozen=None):
return to_fcivec(cisdvec, nelec, orbspin, frozen)
[docs]
def from_fcivec(self, fcivec, nelec, orbspin, frozen=None):
return from_fcivec(fcivec, nelec, orbspin, frozen)
make_rdm1 = make_rdm1
make_rdm2 = make_rdm2
trans_rdm1 = trans_rdm1
[docs]
def amplitudes_to_cisdvec(self, c0, c1, c2):
return amplitudes_to_cisdvec(c0, c1, c2)
[docs]
def cisdvec_to_amplitudes(self, civec, nmo=None, nocc=None, copy=True):
if nmo is None: nmo = self.nmo
if nocc is None: nocc = self.nocc
return cisdvec_to_amplitudes(civec, nmo, nocc, copy=copy)
[docs]
@lib.with_doc(from_ucisdvec.__doc__)
def from_ucisdvec(self, civec, nocc=None, orbspin=None):
if nocc is None: nocc = self.nocc
if orbspin is None:
orbspin = getattr(self.mo_coeff, 'orbspin', None)
if orbspin is not None:
orbspin = orbspin[self.get_frozen_mask()]
assert (orbspin is not None)
return from_ucisdvec(civec, nocc, orbspin=orbspin)
from_rcisdvec = from_ucisdvec
[docs]
@lib.with_doc(to_ucisdvec.__doc__)
def to_ucisdvec(self, civec, orbspin=None):
if orbspin is None:
orbspin = getattr(self.mo_coeff, 'orbspin', None)
if orbspin is not None:
orbspin = orbspin[self.get_frozen_mask()]
return to_ucisdvec(civec, self.nmo, self.nocc, orbspin)
[docs]
def spatial2spin(self, tx, orbspin=None):
if orbspin is None:
orbspin = getattr(self.mo_coeff, 'orbspin', None)
if orbspin is not None:
orbspin = orbspin[self.get_frozen_mask()]
return spatial2spin(tx, orbspin)
[docs]
def spin2spatial(self, tx, orbspin=None):
if orbspin is None:
orbspin = getattr(self.mo_coeff, 'orbspin', None)
if orbspin is not None:
orbspin = orbspin[self.get_frozen_mask()]
return spin2spatial(tx, orbspin)
CISD = GCISD
from pyscf import scf
scf.ghf.GHF.CISD = lib.class_as_method(CISD)
if __name__ == '__main__':
from pyscf import gto
from pyscf import scf
from pyscf import ao2mo
mol = gto.Mole()
mol.verbose = 0
mol.atom = [
['O', ( 0., 0. , 0. )],
['H', ( 0., -0.757, 0.587)],
['H', ( 0., 0.757 , 0.587)],]
mol.basis = {'H': 'sto-3g',
'O': 'sto-3g',}
mol.build()
mf = scf.UHF(mol).run(conv_tol=1e-14)
gmf = scf.addons.convert_to_ghf(mf)
myci = GCISD(gmf)
eris = myci.ao2mo()
ecisd, civec = myci.kernel(eris=eris)
print(ecisd - -0.048878084082066106)
nmo = eris.mo_coeff.shape[1]
rdm1 = myci.make_rdm1(civec, nmo, mol.nelectron)
rdm2 = myci.make_rdm2(civec, nmo, mol.nelectron)
mo = eris.mo_coeff[:7] + eris.mo_coeff[7:]
eri = ao2mo.kernel(mf._eri, mo, compact=False).reshape([nmo]*4)
eri[eris.orbspin[:,None]!=eris.orbspin,:,:] = 0
eri[:,:,eris.orbspin[:,None]!=eris.orbspin] = 0
h1a = reduce(numpy.dot, (mf.mo_coeff[0].T, mf.get_hcore(), mf.mo_coeff[0]))
h1b = reduce(numpy.dot, (mf.mo_coeff[1].T, mf.get_hcore(), mf.mo_coeff[1]))
h1e = numpy.zeros((nmo,nmo))
idxa = eris.orbspin == 0
idxb = eris.orbspin == 1
h1e[idxa[:,None] & idxa] = h1a.ravel()
h1e[idxb[:,None] & idxb] = h1b.ravel()
e2 = (numpy.einsum('ij,ji', h1e, rdm1) +
numpy.einsum('ijkl,ijkl', eri, rdm2) * .5)
e2 += mol.energy_nuc()
print(myci.e_tot - e2) # = 0
print(abs(rdm1 - numpy.einsum('ijkk->ji', rdm2)/(mol.nelectron-1)).sum())
