#!/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>
#
'''
Hartree-Fock for periodic systems with k-point sampling
See Also:
hf.py : Hartree-Fock for periodic systems at a single k-point
'''
from functools import reduce
import numpy as np
import scipy.linalg
from pyscf.scf import hf as mol_hf
from pyscf.scf import uhf as mol_uhf
from pyscf.pbc.scf import khf
from pyscf.pbc.scf import uhf as pbcuhf
from pyscf import lib
from pyscf.lib import logger
from pyscf.pbc.scf import addons
from pyscf.pbc.scf import chkfile # noqa
from pyscf import __config__
PRE_ORTH_METHOD = getattr(__config__, 'pbc_scf_analyze_pre_orth_method', 'ANO')
CHECK_COULOMB_IMAG = getattr(__config__, 'pbc_scf_check_coulomb_imag', True)
canonical_occ = canonical_occ_ = addons.canonical_occ_
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def make_rdm1(mo_coeff_kpts, mo_occ_kpts, **kwargs):
'''Alpha and beta spin one particle density matrices for all k-points.
Returns:
dm_kpts : (2, nkpts, nao, nao) ndarray
'''
nkpts = len(mo_occ_kpts[0])
nao, nmo = mo_coeff_kpts[0][0].shape
def make_dm(mos, occs):
return [np.dot(mos[k]*occs[k], mos[k].T.conj()) for k in range(nkpts)]
dm_kpts =(make_dm(mo_coeff_kpts[0], mo_occ_kpts[0]) +
make_dm(mo_coeff_kpts[1], mo_occ_kpts[1]))
dm = lib.asarray(dm_kpts).reshape(2,nkpts,nao,nao)
return lib.tag_array(dm, mo_coeff=mo_coeff_kpts, mo_occ=mo_occ_kpts)
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def get_fock(mf, h1e=None, s1e=None, vhf=None, dm=None, cycle=-1, diis=None,
diis_start_cycle=None, level_shift_factor=None, damp_factor=None,
fock_last=None):
h1e_kpts, s_kpts, vhf_kpts, dm_kpts = h1e, s1e, vhf, dm
if h1e_kpts is None: h1e_kpts = mf.get_hcore()
if vhf_kpts is None: vhf_kpts = mf.get_veff(mf.cell, dm_kpts)
f_kpts = h1e_kpts + vhf_kpts
if cycle < 0 and diis is None: # Not inside the SCF iteration
return f_kpts
if diis_start_cycle is None:
diis_start_cycle = mf.diis_start_cycle
if level_shift_factor is None:
level_shift_factor = mf.level_shift
if damp_factor is None:
damp_factor = mf.damp
if s_kpts is None: s_kpts = mf.get_ovlp()
if dm_kpts is None: dm_kpts = mf.make_rdm1()
if isinstance(level_shift_factor, (tuple, list, np.ndarray)):
shifta, shiftb = level_shift_factor
else:
shifta = shiftb = level_shift_factor
if isinstance(damp_factor, (tuple, list, np.ndarray)):
dampa, dampb = damp_factor
else:
dampa = dampb = damp_factor
if 0 <= cycle < diis_start_cycle-1 and abs(dampa)+abs(dampb) > 1e-4 and fock_last is not None:
f_a = []
f_b = []
for k in range(len(s_kpts)):
f_a.append(mol_hf.damping(f_kpts[0][k], fock_last[0][k], dampa))
f_b.append(mol_hf.damping(f_kpts[1][k], fock_last[1][k], dampa))
f_kpts = [f_a, f_b]
if diis and cycle >= diis_start_cycle:
f_kpts = diis.update(s_kpts, dm_kpts, f_kpts, mf, h1e_kpts, vhf_kpts, f_prev=fock_last)
if abs(level_shift_factor) > 1e-4:
f_kpts =([mol_hf.level_shift(s, dm_kpts[0,k], f_kpts[0,k], shifta)
for k, s in enumerate(s_kpts)],
[mol_hf.level_shift(s, dm_kpts[1,k], f_kpts[1,k], shiftb)
for k, s in enumerate(s_kpts)])
return lib.asarray(f_kpts)
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def get_fermi(mf, mo_energy_kpts=None, mo_occ_kpts=None):
'''A pair of Fermi level for spin-up and spin-down orbitals
'''
if mo_energy_kpts is None: mo_energy_kpts = mf.mo_energy
if mo_occ_kpts is None: mo_occ_kpts = mf.mo_occ
# mo_energy_kpts and mo_occ_kpts are k-point UHF quantities
assert (mo_energy_kpts[0][0].ndim == 1)
assert (mo_occ_kpts[0][0].ndim == 1)
nocca = sum(mo_occ.sum() for mo_occ in mo_occ_kpts[0])
noccb = sum(mo_occ.sum() for mo_occ in mo_occ_kpts[1])
# nocc may not be perfect integer when smearing is enabled
nocca = int(nocca.round(3))
noccb = int(noccb.round(3))
fermi_a = np.sort(np.hstack(mo_energy_kpts[0]))[nocca-1]
fermi_b = np.sort(np.hstack(mo_energy_kpts[1]))[noccb-1]
for k, mo_e in enumerate(mo_energy_kpts[0]):
mo_occ = mo_occ_kpts[0][k]
if mo_occ[mo_e > fermi_a].sum() > 0.5:
logger.warn(mf, 'Alpha occupied band above Fermi level: \n'
'k=%d, mo_e=%s, mo_occ=%s', k, mo_e, mo_occ)
for k, mo_e in enumerate(mo_energy_kpts[1]):
mo_occ = mo_occ_kpts[1][k]
if mo_occ[mo_e > fermi_b].sum() > 0.5:
logger.warn(mf, 'Beta occupied band above Fermi level: \n'
'k=%d, mo_e=%s, mo_occ=%s', k, mo_e, mo_occ)
return (fermi_a, fermi_b)
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def get_occ(mf, mo_energy_kpts=None, mo_coeff_kpts=None):
'''Label the occupancies for each orbital for sampled k-points.
This is a k-point version of scf.hf.SCF.get_occ
'''
if mo_energy_kpts is None: mo_energy_kpts = mf.mo_energy
nocc_a, nocc_b = mf.nelec
mo_energy = np.sort(np.hstack(mo_energy_kpts[0]))
fermi_a = mo_energy[nocc_a-1]
mo_occ_kpts = [[], []]
for mo_e in mo_energy_kpts[0]:
mo_occ_kpts[0].append((mo_e <= fermi_a).astype(np.double))
if nocc_a < len(mo_energy):
logger.info(mf, 'alpha HOMO = %.12g LUMO = %.12g', fermi_a, mo_energy[nocc_a])
else:
logger.info(mf, 'alpha HOMO = %.12g (no LUMO because of small basis) ', fermi_a)
if nocc_b > 0:
mo_energy = np.sort(np.hstack(mo_energy_kpts[1]))
fermi_b = mo_energy[nocc_b-1]
for mo_e in mo_energy_kpts[1]:
mo_occ_kpts[1].append((mo_e <= fermi_b).astype(np.double))
if nocc_b < len(mo_energy):
logger.info(mf, 'beta HOMO = %.12g LUMO = %.12g', fermi_b, mo_energy[nocc_b])
else:
logger.info(mf, 'beta HOMO = %.12g (no LUMO because of small basis) ', fermi_b)
else:
for mo_e in mo_energy_kpts[1]:
mo_occ_kpts[1].append(np.zeros_like(mo_e))
if mf.verbose >= logger.DEBUG:
np.set_printoptions(threshold=len(mo_energy))
logger.debug(mf, ' k-point alpha mo_energy')
for k,kpt in enumerate(mf.cell.get_scaled_kpts(mf.kpts)):
if (np.count_nonzero(mo_occ_kpts[0][k]) > 0 and
np.count_nonzero(mo_occ_kpts[0][k] == 0) > 0):
logger.debug(mf, ' %2d (%6.3f %6.3f %6.3f) %s %s',
k, kpt[0], kpt[1], kpt[2],
mo_energy_kpts[0][k][mo_occ_kpts[0][k]> 0],
mo_energy_kpts[0][k][mo_occ_kpts[0][k]==0])
else:
logger.debug(mf, ' %2d (%6.3f %6.3f %6.3f) %s',
k, kpt[0], kpt[1], kpt[2], mo_energy_kpts[0][k])
logger.debug(mf, ' k-point beta mo_energy')
for k,kpt in enumerate(mf.cell.get_scaled_kpts(mf.kpts)):
if (np.count_nonzero(mo_occ_kpts[1][k]) > 0 and
np.count_nonzero(mo_occ_kpts[1][k] == 0) > 0):
logger.debug(mf, ' %2d (%6.3f %6.3f %6.3f) %s %s',
k, kpt[0], kpt[1], kpt[2],
mo_energy_kpts[1][k][mo_occ_kpts[1][k]> 0],
mo_energy_kpts[1][k][mo_occ_kpts[1][k]==0])
else:
logger.debug(mf, ' %2d (%6.3f %6.3f %6.3f) %s',
k, kpt[0], kpt[1], kpt[2], mo_energy_kpts[1][k])
np.set_printoptions(threshold=1000)
return mo_occ_kpts
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def energy_elec(mf, dm_kpts=None, h1e_kpts=None, vhf_kpts=None):
'''Following pyscf.scf.hf.energy_elec()
'''
if dm_kpts is None: dm_kpts = mf.make_rdm1()
if h1e_kpts is None: h1e_kpts = mf.get_hcore()
if vhf_kpts is None: vhf_kpts = mf.get_veff(mf.cell, dm_kpts)
nkpts = len(h1e_kpts)
e1 = 1./nkpts * np.einsum('kij,kji', dm_kpts[0], h1e_kpts)
e1+= 1./nkpts * np.einsum('kij,kji', dm_kpts[1], h1e_kpts)
e_coul = 1./nkpts * np.einsum('kij,kji', dm_kpts[0], vhf_kpts[0]) * 0.5
e_coul+= 1./nkpts * np.einsum('kij,kji', dm_kpts[1], vhf_kpts[1]) * 0.5
mf.scf_summary['e1'] = e1.real
mf.scf_summary['e2'] = e_coul.real
logger.debug(mf, 'E1 = %s E_coul = %s', e1, e_coul)
if CHECK_COULOMB_IMAG and abs(e_coul.imag > mf.cell.precision*10):
logger.warn(mf, "Coulomb energy has imaginary part %s. "
"Coulomb integrals (e-e, e-N) may not converge !",
e_coul.imag)
return (e1+e_coul).real, e_coul.real
def _make_rdm1_meta(cell, dm_ao_kpts, kpts, pre_orth_method, s):
from pyscf.lo import orth
from pyscf.pbc.tools import k2gamma
kmesh = k2gamma.kpts_to_kmesh(cell, kpts-kpts[0])
nkpts, nao = dm_ao_kpts[0].shape[:2]
scell, phase = k2gamma.get_phase(cell, kpts, kmesh)
s_sc = k2gamma.to_supercell_ao_integrals(cell, kpts, s, kmesh=kmesh, force_real=False)
orth_coeff = orth.orth_ao(scell, 'meta_lowdin', pre_orth_method, s=s_sc)[:,:nao] # cell 0 only
c_inv = np.dot(orth_coeff.T.conj(), s_sc)
c_inv = lib.einsum('aRp,Rk->kap', c_inv.reshape(nao,nkpts,nao), phase)
dm_a = lib.einsum('kap,kpq,kbq->ab', c_inv, dm_ao_kpts[0], c_inv.conj())
dm_b = lib.einsum('kap,kpq,kbq->ab', c_inv, dm_ao_kpts[1], c_inv.conj())
return (dm_a, dm_b)
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def canonicalize(mf, mo_coeff_kpts, mo_occ_kpts, fock=None):
'''Canonicalization diagonalizes the UHF Fock matrix within occupied,
virtual subspaces separatedly (without change occupancy).
'''
if fock is None:
dm = mf.make_rdm1(mo_coeff_kpts, mo_occ_kpts)
fock = mf.get_fock(dm=dm)
def eig_(fock, mo_coeff, idx, es, cs):
if np.count_nonzero(idx) > 0:
orb = mo_coeff[:,idx]
f1 = reduce(np.dot, (orb.T.conj(), fock, orb))
e, c = scipy.linalg.eigh(f1)
es[idx] = e
cs[:,idx] = np.dot(orb, c)
mo_coeff = [[], []]
mo_energy = [[], []]
for k, mo in enumerate(mo_coeff_kpts[0]):
mo1 = np.empty_like(mo)
mo_e = np.empty_like(mo_occ_kpts[0][k])
occidxa = mo_occ_kpts[0][k] == 1
viridxa = ~occidxa
eig_(fock[0][k], mo, occidxa, mo_e, mo1)
eig_(fock[0][k], mo, viridxa, mo_e, mo1)
mo_coeff[0].append(mo1)
mo_energy[0].append(mo_e)
for k, mo in enumerate(mo_coeff_kpts[1]):
mo1 = np.empty_like(mo)
mo_e = np.empty_like(mo_occ_kpts[1][k])
occidxb = mo_occ_kpts[1][k] == 1
viridxb = ~occidxb
eig_(fock[1][k], mo, occidxb, mo_e, mo1)
eig_(fock[1][k], mo, viridxb, mo_e, mo1)
mo_coeff[1].append(mo1)
mo_energy[1].append(mo_e)
return mo_energy, mo_coeff
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def init_guess_by_chkfile(cell, chkfile_name, project=None, kpts=None):
'''Read the KHF results from checkpoint file, then project it to the
basis defined by ``cell``
Returns:
Density matrix, 3D ndarray
'''
from pyscf import gto
chk_cell, scf_rec = chkfile.load_scf(chkfile_name)
if project is None:
project = not gto.same_basis_set(chk_cell, cell)
if kpts is None:
kpts = scf_rec['kpts']
if 'kpt' in scf_rec:
chk_kpts = scf_rec['kpt'].reshape(-1,3)
elif 'kpts' in scf_rec:
chk_kpts = scf_rec['kpts']
else:
chk_kpts = np.zeros((1,3))
mo = scf_rec['mo_coeff']
mo_occ = scf_rec['mo_occ']
if 'kpts' not in scf_rec: # gamma point or single k-point
if mo.ndim == 2:
mo = np.expand_dims(mo, axis=0)
mo_occ = np.expand_dims(mo_occ, axis=0)
else: # UHF
mo = [np.expand_dims(mo[0], axis=0),
np.expand_dims(mo[1], axis=0)]
mo_occ = [np.expand_dims(mo_occ[0], axis=0),
np.expand_dims(mo_occ[1], axis=0)]
if project:
s = cell.pbc_intor('int1e_ovlp', kpts=kpts)
def fproj(mo, kpts):
if project:
mo = addons.project_mo_nr2nr(chk_cell, mo, cell, kpts)
for k, c in enumerate(mo):
norm = np.einsum('pi,pi->i', c.conj(), s[k].dot(c))
mo[k] /= np.sqrt(norm)
return mo
def makedm(mos, occs):
moa, mob = mos
mos = (fproj(moa, chk_kpts), fproj(mob, chk_kpts))
dm = make_rdm1(mos, occs)
if kpts.shape != chk_kpts.shape or not np.allclose(kpts, chk_kpts):
dm = [addons.project_dm_k2k(cell, dm[0], chk_kpts, kpts),
addons.project_dm_k2k(cell, dm[1], chk_kpts, kpts)]
return np.asarray(dm)
if getattr(mo[0], 'ndim', None) == 2: # KRHF
mo_occa = [(occ>1e-8).astype(np.double) for occ in mo_occ]
mo_occb = [occ-mo_occa[k] for k,occ in enumerate(mo_occ)]
dm = makedm((mo, mo), (mo_occa, mo_occb))
else: # KUHF
dm = makedm(mo, mo_occ)
# Real DM for gamma point
if np.allclose(kpts, 0):
dm = dm.real
return dm
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def dip_moment(cell, dm_kpts, unit='Debye', verbose=logger.NOTE,
grids=None, rho=None, kpts=np.zeros((1,3))):
''' Dipole moment in the cell.
Args:
cell : an instance of :class:`Cell`
dm_kpts (two lists of ndarrays) : KUHF density matrices of k-points
Return:
A list: the dipole moment on x, y and z components
'''
dm_kpts = dm_kpts[0] + dm_kpts[1]
return khf.dip_moment(cell, dm_kpts, unit, verbose, grids, rho, kpts)
get_rho = khf.get_rho
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class KUHF(khf.KSCF):
'''UHF class with k-point sampling.
'''
conv_tol_grad = getattr(__config__, 'pbc_scf_KSCF_conv_tol_grad', None)
init_guess_breaksym = getattr(__config__, 'scf_uhf_init_guess_breaksym', 1)
_keys = {"init_guess_breaksym"}
init_guess_by_1e = pbcuhf.UHF.init_guess_by_1e
init_guess_by_minao = pbcuhf.UHF.init_guess_by_minao
init_guess_by_atom = pbcuhf.UHF.init_guess_by_atom
init_guess_by_huckel = pbcuhf.UHF.init_guess_by_huckel
init_guess_by_mod_huckel = pbcuhf.UHF.init_guess_by_mod_huckel
get_fock = get_fock
get_fermi = get_fermi
get_occ = get_occ
energy_elec = energy_elec
get_rho = get_rho
analyze = khf.analyze
canonicalize = canonicalize
to_gpu = lib.to_gpu
def __init__(self, cell, kpts=np.zeros((1,3)),
exxdiv=getattr(__config__, 'pbc_scf_SCF_exxdiv', 'ewald')):
khf.KSCF.__init__(self, cell, kpts, exxdiv)
self.nelec = None
@property
def nelec(self):
if self._nelec is not None:
return self._nelec
else:
cell = self.cell
nkpts = len(self.kpts)
ne = cell.tot_electrons(nkpts)
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, cell.spin))
return nalpha, nbeta
@nelec.setter
def nelec(self, x):
self._nelec = x
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def dump_flags(self, verbose=None):
khf.KSCF.dump_flags(self, verbose)
logger.info(self, 'number of electrons per cell '
'alpha = %d beta = %d', *self.nelec)
return self
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def get_init_guess(self, cell=None, key='minao', s1e=None):
if s1e is None:
s1e = self.get_ovlp(cell)
dm_kpts = mol_hf.SCF.get_init_guess(self, cell, key)
assert dm_kpts.shape[0] == 2
nkpts = len(self.kpts)
if dm_kpts.ndim != 4:
# dm[spin,nao,nao] at gamma point -> dm_kpts[spin,nkpts,nao,nao]
dm_kpts = np.repeat(dm_kpts[:,None,:,:], nkpts, axis=1)
ne = lib.einsum('xkij,kji->x', dm_kpts, s1e).real
nelec = np.asarray(self.nelec)
if np.any(abs(ne - nelec) > 0.01*nkpts):
logger.debug(self, 'Big error detected in the electron number '
'of initial guess density matrix (Ne/cell = %g)!\n'
' This can cause huge error in Fock matrix and '
'lead to instability in SCF for low-dimensional '
'systems.\n DM is normalized wrt the number '
'of electrons %s', ne.mean()/nkpts, nelec/nkpts)
dm_kpts *= (nelec / ne).reshape(2,-1,1,1)
return dm_kpts
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def get_veff(self, cell=None, dm_kpts=None, dm_last=0, vhf_last=0, hermi=1,
kpts=None, kpts_band=None):
if dm_kpts is None:
dm_kpts = self.make_rdm1()
vj, vk = self.get_jk(cell, dm_kpts, hermi, kpts, kpts_band)
vhf = vj[0] + vj[1] - vk
return vhf
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def get_grad(self, mo_coeff_kpts, mo_occ_kpts, fock=None):
if fock is None:
dm1 = self.make_rdm1(mo_coeff_kpts, mo_occ_kpts)
fock = self.get_hcore(self.cell, self.kpts) + self.get_veff(self.cell, dm1)
def grad(mo, mo_occ, fock):
occidx = mo_occ > 0
viridx = ~occidx
g = reduce(np.dot, (mo[:,viridx].T.conj(), fock, mo[:,occidx]))
return g.ravel()
nkpts = len(mo_occ_kpts[0])
grad_kpts = [grad(mo_coeff_kpts[0][k], mo_occ_kpts[0][k], fock[0][k])
for k in range(nkpts)]
grad_kpts+= [grad(mo_coeff_kpts[1][k], mo_occ_kpts[1][k], fock[1][k])
for k in range(nkpts)]
return np.hstack(grad_kpts)
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def eig(self, h_kpts, s_kpts):
e_a, c_a = khf.KSCF.eig(self, h_kpts[0], s_kpts)
e_b, c_b = khf.KSCF.eig(self, h_kpts[1], s_kpts)
return (e_a,e_b), (c_a,c_b)
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def make_rdm1(self, mo_coeff_kpts=None, mo_occ_kpts=None, **kwargs):
if mo_coeff_kpts is None: mo_coeff_kpts = self.mo_coeff
if mo_occ_kpts is None: mo_occ_kpts = self.mo_occ
return make_rdm1(mo_coeff_kpts, mo_occ_kpts, **kwargs)
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def get_bands(self, kpts_band, cell=None, dm_kpts=None, kpts=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)
'''
if cell is None: cell = self.cell
if dm_kpts is None: dm_kpts = self.make_rdm1()
if kpts is None: kpts = self.kpts
kpts_band = np.asarray(kpts_band)
single_kpt_band = (kpts_band.ndim == 1)
kpts_band = kpts_band.reshape(-1,3)
fock = self.get_hcore(cell, kpts_band)
fock = fock + self.get_veff(cell, dm_kpts, kpts=kpts, kpts_band=kpts_band)
s1e = self.get_ovlp(cell, kpts_band)
(e_a,e_b), (c_a,c_b) = self.eig(fock, s1e)
if single_kpt_band:
e_a = e_a[0]
e_b = e_b[0]
c_a = c_a[0]
c_b = c_b[0]
return (e_a,e_b), (c_a,c_b)
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def init_guess_by_chkfile(self, chk=None, project=True, kpts=None):
if chk is None: chk = self.chkfile
if kpts is None: kpts = self.kpts
return init_guess_by_chkfile(self.cell, chk, project, kpts)
[docs]
def mulliken_pop(self):
raise NotImplementedError
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@lib.with_doc(dip_moment.__doc__)
def dip_moment(self, cell=None, dm=None, unit='Debye', verbose=logger.NOTE,
**kwargs):
if cell is None: cell = self.cell
if dm is None: dm = self.make_rdm1()
rho = kwargs.pop('rho', None)
if rho is None:
rho = self.get_rho(dm)
return dip_moment(cell, dm, unit, verbose, rho=rho, kpts=self.kpts, **kwargs)
[docs]
@lib.with_doc(mol_uhf.spin_square.__doc__)
def spin_square(self, mo_coeff=None, s=None):
'''Treating the k-point sampling wfn as a giant Slater determinant,
the spin_square value is the <S^2> of the giant determinant.
'''
nkpts = len(self.kpts)
if mo_coeff is None:
mo_a = [self.mo_coeff[0][k][:,self.mo_occ[0][k]>0] for k in range(nkpts)]
mo_b = [self.mo_coeff[1][k][:,self.mo_occ[1][k]>0] for k in range(nkpts)]
else:
mo_a, mo_b = mo_coeff
if s is None:
s = self.get_ovlp()
nelec_a = sum([mo_a[k].shape[1] for k in range(nkpts)])
nelec_b = sum([mo_b[k].shape[1] for k in range(nkpts)])
ssxy = (nelec_a + nelec_b) * .5
for k in range(nkpts):
sij = reduce(np.dot, (mo_a[k].T.conj(), s[k], mo_b[k]))
ssxy -= np.einsum('ij,ij->', sij.conj(), sij).real
ssz = (nelec_b-nelec_a)**2 * .25
ss = ssxy + ssz
s = np.sqrt(ss+.25) - .5
return ss, s*2+1
[docs]
def stability(self,
internal=getattr(__config__, 'pbc_scf_KSCF_stability_internal', True),
external=getattr(__config__, 'pbc_scf_KSCF_stability_external', False),
verbose=None):
from pyscf.pbc.scf.stability import uhf_stability
return uhf_stability(self, internal, external, verbose)
[docs]
def nuc_grad_method(self):
from pyscf.pbc.grad import kuhf
return kuhf.Gradients(self)
[docs]
def to_ks(self, xc='HF'):
'''Convert to RKS object.
'''
from pyscf.pbc import dft
return self._transfer_attrs_(dft.KUKS(self.cell, self.kpts, xc=xc))
[docs]
def convert_from_(self, mf):
'''Convert given mean-field object to KUHF'''
addons.convert_to_uhf(mf, self)
return self
