#!/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.
#
# Author: Qiming Sun <osirpt.sun@gmail.com>
#
import ctypes
import numpy
from pyscf import lib
from pyscf import ao2mo
from pyscf.fci import direct_spin1
from pyscf.fci import direct_spin1_symm
from pyscf.fci import selected_ci
from pyscf.fci import selected_ci_symm
from pyscf.fci import selected_ci_spin0
libfci = direct_spin1.libfci
[docs]
def contract_2e(eri, civec_strs, norb, nelec, link_index=None, orbsym=None):
ci_coeff, nelec, ci_strs = selected_ci._unpack(civec_strs, nelec)
if link_index is None:
link_index = selected_ci._all_linkstr_index(ci_strs, norb, nelec)
cd_indexa, dd_indexa, cd_indexb, dd_indexb = link_index
na, nlinka = nb, nlinkb = cd_indexa.shape[:2]
eri = ao2mo.restore(1, eri, norb)
eri1 = eri.transpose(0,2,1,3) - eri.transpose(0,2,3,1)
idx,idy = numpy.tril_indices(norb, -1)
idx = idx * norb + idy
eri1 = lib.take_2d(eri1.reshape(norb**2,-1), idx, idx) * 2
lib.transpose_sum(eri1, inplace=True)
eri1 *= .5
eri1, dd_indexa, dimirrep = selected_ci_symm.reorder4irrep(eri1, norb, dd_indexa, orbsym, -1)
fcivec = ci_coeff.reshape(na,nb)
ci1 = numpy.zeros_like(fcivec)
# (aa|aa)
if nelec[0] > 1:
ma, mlinka = mb, mlinkb = dd_indexa.shape[:2]
libfci.SCIcontract_2e_aaaa_symm(eri1.ctypes.data_as(ctypes.c_void_p),
fcivec.ctypes.data_as(ctypes.c_void_p),
ci1.ctypes.data_as(ctypes.c_void_p),
ctypes.c_int(norb),
ctypes.c_int(na), ctypes.c_int(nb),
ctypes.c_int(ma), ctypes.c_int(mlinka),
dd_indexa.ctypes.data_as(ctypes.c_void_p),
dimirrep.ctypes.data_as(ctypes.c_void_p),
ctypes.c_int(len(dimirrep)))
h_ps = numpy.einsum('pqqs->ps', eri) * (.5/nelec[0])
eri1 = eri.copy()
for k in range(norb):
eri1[:,:,k,k] += h_ps
eri1[k,k,:,:] += h_ps
eri1 = ao2mo.restore(4, eri1, norb)
lib.transpose_sum(eri1, inplace=True)
eri1 *= .5
eri1, cd_indexa, dimirrep = selected_ci_symm.reorder4irrep(eri1, norb, cd_indexa, orbsym)
# (bb|aa)
libfci.SCIcontract_2e_bbaa_symm(eri1.ctypes.data_as(ctypes.c_void_p),
fcivec.ctypes.data_as(ctypes.c_void_p),
ci1.ctypes.data_as(ctypes.c_void_p),
ctypes.c_int(norb),
ctypes.c_int(na), ctypes.c_int(nb),
ctypes.c_int(nlinka), ctypes.c_int(nlinkb),
cd_indexa.ctypes.data_as(ctypes.c_void_p),
cd_indexa.ctypes.data_as(ctypes.c_void_p),
dimirrep.ctypes.data_as(ctypes.c_void_p),
ctypes.c_int(len(dimirrep)))
lib.transpose_sum(ci1, inplace=True)
return selected_ci._as_SCIvector(ci1.reshape(ci_coeff.shape), ci_strs)
[docs]
def kernel(h1e, eri, norb, nelec, ci0=None, level_shift=1e-3, tol=1e-10,
lindep=1e-14, max_cycle=50, max_space=12, nroots=1,
davidson_only=False, pspace_size=400, orbsym=None, wfnsym=None,
select_cutoff=1e-3, ci_coeff_cutoff=1e-3, ecore=0, **kwargs):
return direct_spin1._kfactory(SelectedCI, h1e, eri, norb, nelec, ci0,
level_shift, tol, lindep, max_cycle,
max_space, nroots, davidson_only,
pspace_size, select_cutoff=select_cutoff,
ci_coeff_cutoff=ci_coeff_cutoff, ecore=ecore,
**kwargs)
make_rdm1s = selected_ci.make_rdm1s
make_rdm2s = selected_ci.make_rdm2s
make_rdm1 = selected_ci.make_rdm1
make_rdm2 = selected_ci.make_rdm2
trans_rdm1s = selected_ci.trans_rdm1s
trans_rdm1 = selected_ci.trans_rdm1
[docs]
class SelectedCI(selected_ci_symm.SelectedCI):
[docs]
def contract_2e(self, eri, civec_strs, norb, nelec, link_index=None,
orbsym=None, **kwargs):
if orbsym is None:
orbsym = self.orbsym
if getattr(civec_strs, '_strs', None) is not None:
self._strs = civec_strs._strs
else:
assert (civec_strs.size == len(self._strs[0])*len(self._strs[1]))
civec_strs = selected_ci._as_SCIvector(civec_strs, self._strs)
return contract_2e(eri, civec_strs, norb, nelec, link_index, orbsym)
make_hdiag = staticmethod(selected_ci_spin0.make_hdiag)
enlarge_space = selected_ci_spin0.enlarge_space
SCI = SelectedCI
if __name__ == '__main__':
from functools import reduce
from pyscf import gto
from pyscf import scf
from pyscf import symm
mol = gto.Mole()
mol.verbose = 0
mol.output = None
mol.atom = [
['O', ( 0., 0. , 0. )],
['H', ( 0., -0.757, 0.587)],
['H', ( 0., 0.757 , 0.587)],]
mol.basis = 'sto-3g'
mol.symmetry = 1
mol.build()
m = scf.RHF(mol).run()
norb = m.mo_coeff.shape[1]
nelec = mol.nelectron - 2
h1e = reduce(numpy.dot, (m.mo_coeff.T, scf.hf.get_hcore(mol), m.mo_coeff))
eri = ao2mo.incore.full(m._eri, m.mo_coeff)
orbsym = symm.label_orb_symm(mol, mol.irrep_id, mol.symm_orb, m.mo_coeff)
myci = SelectedCI().set(orbsym=orbsym)
e1, c1 = myci.kernel(h1e, eri, norb, nelec)
myci = direct_spin1_symm.FCISolver().set(orbsym=orbsym)
e2, c2 = myci.kernel(h1e, eri, norb, nelec)
print(e1 - e2)
