#!/usr/bin/env python
# Copyright 2014-2019 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>
#
'''
Restricted open-shell Hartree-Fock for periodic systems at a single k-point
See Also:
pyscf/pbc/scf/khf.py : Hartree-Fock for periodic systems with k-point sampling
'''
import numpy as np
from pyscf import lib
from pyscf.lib import logger
from pyscf.scf import rohf as mol_rohf
from pyscf.pbc.scf import hf as pbchf
from pyscf.pbc.scf import uhf as pbcuhf
from pyscf import __config__
get_fock = mol_rohf.get_fock
get_occ = mol_rohf.get_occ
get_grad = mol_rohf.get_grad
make_rdm1 = mol_rohf.make_rdm1
energy_elec = mol_rohf.energy_elec
dip_moment = pbcuhf.dip_moment
get_rho = pbcuhf.get_rho
[docs]
class ROHF(pbchf.RHF, mol_rohf.ROHF):
'''ROHF class for PBCs.
'''
get_init_guess = pbcuhf.UHF.get_init_guess
init_guess_by_chkfile = pbcuhf.UHF.init_guess_by_chkfile
init_guess_by_minao = mol_rohf.ROHF.init_guess_by_minao
init_guess_by_atom = mol_rohf.ROHF.init_guess_by_atom
init_guess_by_huckel = mol_rohf.ROHF.init_guess_by_huckel
init_guess_by_mod_huckel = mol_rohf.ROHF.init_guess_by_mod_huckel
eig = mol_rohf.ROHF.eig
get_fock = mol_rohf.ROHF.get_fock
get_occ = mol_rohf.ROHF.get_occ
get_grad = mol_rohf.ROHF.get_grad
get_rho = get_rho
make_rdm1 = mol_rohf.ROHF.make_rdm1
energy_elec = mol_rohf.ROHF.energy_elec
analyze = mol_rohf.ROHF.analyze
canonicalize = mol_rohf.ROHF.canonicalize
spin_square = mol_rohf.ROHF.spin_square
stability = mol_rohf.ROHF.stability
dip_moment = pbchf.SCF.dip_moment
def __init__(self, cell, kpt=np.zeros(3),
exxdiv=getattr(__config__, 'pbc_scf_SCF_exxdiv', 'ewald')):
pbchf.SCF.__init__(self, cell, kpt, exxdiv)
self.nelec = None
@property
def nelec(self):
if self._nelec is not None:
return self._nelec
else:
cell = self.cell
ne = cell.nelectron
nalpha = (ne + cell.spin) // 2
nbeta = nalpha - cell.spin
if nalpha + nbeta != ne:
raise RuntimeError('Electron number %d and spin %d are not consistent\n'
'Note cell.spin = 2S = Nalpha - Nbeta, not 2S+1' %
(ne, self.spin))
return nalpha, nbeta
@nelec.setter
def nelec(self, x):
self._nelec = x
[docs]
def dump_flags(self, verbose=None):
pbchf.SCF.dump_flags(self, verbose)
logger.info(self, 'number of electrons per cell '
'alpha = %d beta = %d', *self.nelec)
return self
[docs]
def get_veff(self, cell=None, dm=None, dm_last=0, vhf_last=0, hermi=1,
kpt=None, kpts_band=None):
if cell is None: cell = self.cell
if dm is None: dm = self.make_rdm1()
if kpt is None: kpt = self.kpt
if isinstance(dm, np.ndarray) and dm.ndim == 2:
dm = np.asarray((dm*.5,dm*.5))
if getattr(dm, 'mo_coeff', None) is not None:
mo_coeff = dm.mo_coeff
mo_occ_a = (dm.mo_occ > 0).astype(np.double)
mo_occ_b = (dm.mo_occ ==2).astype(np.double)
dm = lib.tag_array(dm, mo_coeff=(mo_coeff,mo_coeff),
mo_occ=(mo_occ_a,mo_occ_b))
vj, vk = self.get_jk(cell, dm, hermi, kpt, kpts_band)
vhf = vj[0] + vj[1] - vk
return vhf
[docs]
def get_bands(self, kpts_band, cell=None, dm=None, kpt=None):
'''Get energy bands at the given (arbitrary) 'band' k-points.
Returns:
mo_energy : (nmo,) ndarray or a list of (nmo,) ndarray
Bands energies E_n(k)
mo_coeff : (nao, nmo) ndarray or a list of (nao,nmo) ndarray
Band orbitals psi_n(k)
'''
raise NotImplementedError
[docs]
def init_guess_by_1e(self, cell=None):
if cell is None: cell = self.cell
if cell.dimension < 3:
logger.warn(self, 'Hcore initial guess is not recommended in '
'the SCF of low-dimensional systems.')
return mol_rohf.ROHF.init_guess_by_1e(self, cell)
[docs]
def to_ks(self, xc='HF'):
'''Convert to RKS object.
'''
from pyscf.pbc import dft
return self._transfer_attrs_(dft.ROKS(self.cell, self.kpt, xc=xc))