def initialize_paw_corrections(self, pd, soft=False):
wfs = self.calc.wfs
q_v = pd.K_qv[0]
optical_limit = np.allclose(q_v, 0)
G_Gv = pd.G_Qv[pd.Q_qG[0]] + q_v
if optical_limit:
G_Gv[0] = 1
pos_av = np.dot(self.spos_ac, pd.gd.cell_cv)
# Collect integrals for all species:
Q_xGii = {}
for id, atomdata in wfs.setups.setups.items():
if soft:
ghat = PWLFC([atomdata.ghat_l], pd)
ghat.set_positions(np.zeros((1, 3)))
Q_LG = ghat.expand()
Q_Gii = np.dot(atomdata.Delta_iiL, Q_LG).T
else:
Q_Gii = two_phi_planewave_integrals(G_Gv, atomdata)
ni = atomdata.ni
Q_Gii.shape = (-1, ni, ni)
Q_xGii[id] = Q_Gii
Q_aGii = []
for a, atomdata in enumerate(wfs.setups):
id = wfs.setups.id_a[a]
Q_Gii = Q_xGii[id]
x_G = np.exp(-1j * np.dot(G_Gv, pos_av[a]))
Q_aGii.append(x_G[:, np.newaxis, np.newaxis] * Q_Gii)
if optical_limit:
Q_aGii[a][0] = atomdata.dO_ii
return Q_aGii
def initialize_paw_corrections(self, pd, soft=False):
wfs = self.calc.wfs
q_v = pd.K_qv[0]
optical_limit = np.allclose(q_v, 0)
G_Gv = pd.get_reciprocal_vectors()
if optical_limit:
G_Gv[0] = 1
pos_av = np.dot(self.spos_ac, pd.gd.cell_cv)
# Collect integrals for all species:
Q_xGii = {}
for id, atomdata in wfs.setups.setups.items():
if soft:
ghat = PWLFC([atomdata.ghat_l], pd)
ghat.set_positions(np.zeros((1, 3)))
Q_LG = ghat.expand()
Q_Gii = np.dot(atomdata.Delta_iiL, Q_LG).T
else:
Q_Gii = two_phi_planewave_integrals(G_Gv, atomdata)
ni = atomdata.ni
Q_Gii.shape = (-1, ni, ni)
Q_xGii[id] = Q_Gii
Q_aGii = []
for a, atomdata in enumerate(wfs.setups):
id = wfs.setups.id_a[a]
Q_Gii = Q_xGii[id]
x_G = np.exp(-1j * np.dot(G_Gv, pos_av[a]))
Q_aGii.append(x_G[:, np.newaxis, np.newaxis] * Q_Gii)
if optical_limit:
Q_aGii[a][0] = atomdata.dO_ii
return Q_aGii
class HybridXC(HybridXCBase):
orbital_dependent = True
def __init__(self, name, hybrid=None, xc=None,
alpha=None,
gamma_point=1,
method='standard',
bandstructure=False,
logfilename='-', bands=None,
fcut=1e-10,
molecule=False,
qstride=1,
world=None):
"""Mix standard functionals with exact exchange.
name: str
Name of functional: EXX, PBE0, HSE03, HSE06
hybrid: float
Fraction of exact exchange.
xc: str or XCFunctional object
Standard DFT functional with scaled down exchange.
method: str
Use 'standard' standard formula and 'acdf for
adiabatic-connection dissipation fluctuation formula.
alpha: float
XXX describe
gamma_point: bool
0: Skip k2-k1=0 interactions.
1: Use the alpha method.
2: Integrate the gamma point.
bandstructure: bool
Calculate bandstructure instead of just the total energy.
bands: list of int
List of bands to calculate bandstructure for. Default is
all bands.
molecule: bool
Decouple electrostatic interactions between periodically
repeated images.
fcut: float
Threshold for empty band.
"""
self.alpha = alpha
self.fcut = fcut
self.gamma_point = gamma_point
self.method = method
self.bandstructure = bandstructure
self.bands = bands
self.fd = logfilename
self.write_timing_information = True
HybridXCBase.__init__(self, name, hybrid, xc)
# EXX energies:
self.exx = None # total
self.evv = None # valence-valence (pseudo part)
self.evvacdf = None # valence-valence (pseudo part)
self.devv = None # valence-valence (PAW correction)
self.evc = None # valence-core
self.ecc = None # core-core
self.exx_skn = None # bandstructure
self.qlatest = None
if world is None:
world = mpi.world
self.world = world
self.molecule = molecule
if isinstance(qstride, int):
qstride = [qstride] * 3
self.qstride_c = np.asarray(qstride)
self.timer = Timer()
def log(self, *args, **kwargs):
prnt(file=self.fd, *args, **kwargs)
self.fd.flush()
def calculate_radial(self, rgd, n_sLg, Y_L, v_sg,
dndr_sLg=None, rnablaY_Lv=None,
tau_sg=None, dedtau_sg=None):
return self.xc.calculate_radial(rgd, n_sLg, Y_L, v_sg,
dndr_sLg, rnablaY_Lv)
def calculate_paw_correction(self, setup, D_sp, dEdD_sp=None,
addcoredensity=True, a=None):
return self.xc.calculate_paw_correction(setup, D_sp, dEdD_sp,
addcoredensity, a)
def initialize(self, dens, ham, wfs, occupations):
assert wfs.bd.comm.size == 1
self.xc.initialize(dens, ham, wfs, occupations)
self.dens = dens
self.wfs = wfs
# Make a k-point descriptor that is not distributed
# (self.kd.comm is serial_comm):
self.kd = wfs.kd.copy()
self.fd = logfile(self.fd, self.world.rank)
wfs.initialize_wave_functions_from_restart_file()
def set_positions(self, spos_ac):
self.spos_ac = spos_ac
def calculate(self, gd, n_sg, v_sg=None, e_g=None):
# Normal XC contribution:
exc = self.xc.calculate(gd, n_sg, v_sg, e_g)
# Add EXX contribution:
return exc + self.exx * self.hybrid
def calculate_exx(self):
"""Non-selfconsistent calculation."""
self.timer.start('EXX')
self.timer.start('Initialization')
kd = self.kd
wfs = self.wfs
if fftw.FFTPlan is fftw.NumpyFFTPlan:
self.log('NOT USING FFTW !!')
self.log('Spins:', self.wfs.nspins)
W = max(1, self.wfs.kd.comm.size // self.wfs.nspins)
# Are the k-points distributed?
kparallel = (W > 1)
# Find number of occupied bands:
self.nocc_sk = np.zeros((self.wfs.nspins, kd.nibzkpts), int)
for kpt in self.wfs.kpt_u:
for n, f in enumerate(kpt.f_n):
if abs(f) < self.fcut:
self.nocc_sk[kpt.s, kpt.k] = n
break
else:
self.nocc_sk[kpt.s, kpt.k] = self.wfs.bd.nbands
self.wfs.kd.comm.sum(self.nocc_sk)
noccmin = self.nocc_sk.min()
noccmax = self.nocc_sk.max()
self.log('Number of occupied bands (min, max): %d, %d' %
(noccmin, noccmax))
self.log('Number of valence electrons:', self.wfs.setups.nvalence)
if self.bandstructure:
self.log('Calculating eigenvalue shifts.')
# allocate array for eigenvalue shifts:
self.exx_skn = np.zeros((self.wfs.nspins,
kd.nibzkpts,
self.wfs.bd.nbands))
if self.bands is None:
noccmax = self.wfs.bd.nbands
else:
noccmax = max(max(self.bands) + 1, noccmax)
N_c = self.kd.N_c
vol = wfs.gd.dv * wfs.gd.N_c.prod()
if self.alpha is None:
alpha = 6 * vol**(2 / 3.0) / pi**2
else:
alpha = self.alpha
if self.gamma_point == 1:
if alpha == 0.0:
qvol = (2*np.pi)**3 / vol / N_c.prod()
self.gamma = 4*np.pi * (3*qvol / (4*np.pi))**(1/3.) / qvol
else:
self.gamma = self.calculate_gamma(vol, alpha)
else:
kcell_cv = wfs.gd.cell_cv.copy()
kcell_cv[0] *= N_c[0]
kcell_cv[1] *= N_c[1]
kcell_cv[2] *= N_c[2]
self.gamma = madelung(kcell_cv) * vol * N_c.prod() / (4 * np.pi)
self.log('Value of alpha parameter: %.3f Bohr^2' % alpha)
self.log('Value of gamma parameter: %.3f Bohr^2' % self.gamma)
# Construct all possible q=k2-k1 vectors:
Nq_c = (N_c - 1) // self.qstride_c
i_qc = np.indices(Nq_c * 2 + 1, float).transpose(
(1, 2, 3, 0)).reshape((-1, 3))
self.bzq_qc = (i_qc - Nq_c) / N_c * self.qstride_c
self.q0 = ((Nq_c * 2 + 1).prod() - 1) // 2 # index of q=(0,0,0)
assert not self.bzq_qc[self.q0].any()
# Count number of pairs for each q-vector:
self.npairs_q = np.zeros(len(self.bzq_qc), int)
for s in range(kd.nspins):
for k1 in range(kd.nibzkpts):
for k2 in range(kd.nibzkpts):
for K2, q, n1_n, n2 in self.indices(s, k1, k2):
self.npairs_q[q] += len(n1_n)
self.npairs0 = self.npairs_q.sum() # total number of pairs
self.log('Number of pairs:', self.npairs0)
# Distribute q-vectors to Q processors:
Q = self.world.size // self.wfs.kd.comm.size
myrank = self.world.rank // self.wfs.kd.comm.size
rank = 0
N = 0
myq = []
nq = 0
for q, n in enumerate(self.npairs_q):
if n > 0:
nq += 1
if rank == myrank:
myq.append(q)
N += n
if N >= (rank + 1.0) * self.npairs0 / Q:
rank += 1
assert len(myq) > 0, 'Too few q-vectors for too many processes!'
self.bzq_qc = self.bzq_qc[myq]
try:
self.q0 = myq.index(self.q0)
except ValueError:
self.q0 = None
self.log('%d x %d x %d k-points' % tuple(self.kd.N_c))
self.log('Distributing %d IBZ k-points over %d process(es).' %
(kd.nibzkpts, self.wfs.kd.comm.size))
self.log('Distributing %d q-vectors over %d process(es).' % (nq, Q))
# q-point descriptor for my q-vectors:
qd = KPointDescriptor(self.bzq_qc)
# Plane-wave descriptor for all wave-functions:
self.pd = PWDescriptor(wfs.pd.ecut, wfs.gd,
dtype=wfs.pd.dtype, kd=kd)
# Plane-wave descriptor pair-densities:
self.pd2 = PWDescriptor(self.dens.pd2.ecut, self.dens.gd,
dtype=wfs.dtype, kd=qd)
self.log('Cutoff energies:')
self.log(' Wave functions: %10.3f eV' %
(self.pd.ecut * Hartree))
self.log(' Density: %10.3f eV' %
(self.pd2.ecut * Hartree))
# Calculate 1/|G+q|^2 with special treatment of |G+q|=0:
G2_qG = self.pd2.G2_qG
if self.q0 is None:
if self.omega is None:
self.iG2_qG = [1.0 / G2_G for G2_G in G2_qG]
else:
self.iG2_qG = [(1.0 / G2_G *
(1 - np.exp(-G2_G / (4 * self.omega**2))))
for G2_G in G2_qG]
else:
G2_qG[self.q0][0] = 117.0 # avoid division by zero
if self.omega is None:
self.iG2_qG = [1.0 / G2_G for G2_G in G2_qG]
self.iG2_qG[self.q0][0] = self.gamma
else:
self.iG2_qG = [(1.0 / G2_G *
(1 - np.exp(-G2_G / (4 * self.omega**2))))
for G2_G in G2_qG]
self.iG2_qG[self.q0][0] = 1 / (4 * self.omega**2)
G2_qG[self.q0][0] = 0.0 # restore correct value
# Compensation charges:
self.ghat = PWLFC([setup.ghat_l for setup in wfs.setups], self.pd2)
self.ghat.set_positions(self.spos_ac)
if self.molecule:
self.initialize_gaussian()
self.log('Value of beta parameter: %.3f 1/Bohr^2' % self.beta)
self.timer.stop('Initialization')
# Ready ... set ... go:
self.t0 = time()
self.npairs = 0
self.evv = 0.0
self.evvacdf = 0.0
for s in range(self.wfs.nspins):
kpt1_q = [KPoint(self.wfs, noccmax).initialize(kpt)
for kpt in self.wfs.kpt_u if kpt.s == s]
kpt2_q = kpt1_q[:]
if len(kpt1_q) == 0:
# No s-spins on this CPU:
continue
# Send and receive ranks:
srank = self.wfs.kd.get_rank_and_index(
s, (kpt1_q[0].k - 1) % kd.nibzkpts)[0]
rrank = self.wfs.kd.get_rank_and_index(
s, (kpt1_q[-1].k + 1) % kd.nibzkpts)[0]
# Shift k-points kd.nibzkpts - 1 times:
for i in range(kd.nibzkpts):
if i < kd.nibzkpts - 1:
if kparallel:
kpt = kpt2_q[-1].next(self.wfs)
kpt.start_receiving(rrank)
kpt2_q[0].start_sending(srank)
else:
kpt = kpt2_q[0]
self.timer.start('Calculate')
for kpt1, kpt2 in zip(kpt1_q, kpt2_q):
# Loop over all k-points that k2 can be mapped to:
for K2, q, n1_n, n2 in self.indices(s, kpt1.k, kpt2.k):
self.apply(K2, q, kpt1, kpt2, n1_n, n2)
self.timer.stop('Calculate')
if i < kd.nibzkpts - 1:
self.timer.start('Wait')
if kparallel:
kpt.wait()
kpt2_q[0].wait()
self.timer.stop('Wait')
kpt2_q.pop(0)
kpt2_q.append(kpt)
self.evv = self.world.sum(self.evv)
self.evvacdf = self.world.sum(self.evvacdf)
self.calculate_exx_paw_correction()
if self.method == 'standard':
self.exx = self.evv + self.devv + self.evc + self.ecc
elif self.method == 'acdf':
self.exx = self.evvacdf + self.devv + self.evc + self.ecc
else:
1 / 0
self.log('Exact exchange energy:')
for txt, e in [
('core-core', self.ecc),
('valence-core', self.evc),
('valence-valence (pseudo, acdf)', self.evvacdf),
('valence-valence (pseudo, standard)', self.evv),
('valence-valence (correction)', self.devv),
('total (%s)' % self.method, self.exx)]:
self.log(' %-36s %14.6f eV' % (txt + ':', e * Hartree))
self.log('Total time: %10.3f seconds' % (time() - self.t0))
self.npairs = self.world.sum(self.npairs)
assert self.npairs == self.npairs0
self.timer.stop('EXX')
self.timer.write(self.fd)
def calculate_gamma(self, vol, alpha):
if self.molecule:
return 0.0
N_c = self.kd.N_c
offset_c = (N_c + 1) % 2 * 0.5 / N_c
bzq_qc = monkhorst_pack(N_c) + offset_c
qd = KPointDescriptor(bzq_qc)
pd = PWDescriptor(self.wfs.pd.ecut, self.wfs.gd, kd=qd)
gamma = (vol / (2 * pi)**2 * sqrt(pi / alpha) *
self.kd.nbzkpts)
for G2_G in pd.G2_qG:
if G2_G[0] < 1e-7:
G2_G = G2_G[1:]
gamma -= np.dot(np.exp(-alpha * G2_G), G2_G**-1)
return gamma / self.qstride_c.prod()
def indices(self, s, k1, k2):
"""Generator for (K2, q, n1, n2) indices for (k1, k2) pair.
s: int
Spin index.
k1: int
Index of k-point in the IBZ.
k2: int
Index of k-point in the IBZ.
Returns (K, q, n1_n, n2), where K then index of the k-point in
the BZ that k2 is mapped to, q is the index of the q-vector
between K and k1, and n1_n is a list of bands that should be
combined with band n2."""
for K, k in enumerate(self.kd.bz2ibz_k):
if k == k2:
for K, q, n1_n, n2 in self._indices(s, k1, k2, K):
yield K, q, n1_n, n2
def _indices(self, s, k1, k2, K2):
k1_c = self.kd.ibzk_kc[k1]
k2_c = self.kd.bzk_kc[K2]
q_c = k2_c - k1_c
q = abs(self.bzq_qc - q_c).sum(1).argmin()
if abs(self.bzq_qc[q] - q_c).sum() > 1e-7:
return
if self.gamma_point == 0 and q == self.q0:
return
nocc1 = self.nocc_sk[s, k1]
nocc2 = self.nocc_sk[s, k2]
# Is k2 in the IBZ?
is_ibz2 = (self.kd.ibz2bz_k[k2] == K2)
for n2 in range(self.wfs.bd.nbands):
# Find range of n1's (from n1a to n1b-1):
if is_ibz2:
# We get this combination twice, so let's only do half:
if k1 >= k2:
n1a = n2
else:
n1a = n2 + 1
else:
n1a = 0
n1b = self.wfs.bd.nbands
if self.bandstructure:
if n2 >= nocc2:
n1b = min(n1b, nocc1)
else:
if n2 >= nocc2:
break
n1b = min(n1b, nocc1)
if self.bands is not None:
assert self.bandstructure
n1_n = []
for n1 in range(n1a, n1b):
if (n1 in self.bands and n2 < nocc2 or
is_ibz2 and n2 in self.bands and n1 < nocc1):
n1_n.append(n1)
n1_n = np.array(n1_n)
else:
n1_n = np.arange(n1a, n1b)
if len(n1_n) == 0:
continue
yield K2, q, n1_n, n2
def apply(self, K2, q, kpt1, kpt2, n1_n, n2):
k20_c = self.kd.ibzk_kc[kpt2.k]
k2_c = self.kd.bzk_kc[K2]
if k2_c.any():
self.timer.start('Initialize plane waves')
eik2r_R = self.wfs.gd.plane_wave(k2_c)
eik20r_R = self.wfs.gd.plane_wave(k20_c)
self.timer.stop('Initialize plane waves')
else:
eik2r_R = 1.0
eik20r_R = 1.0
w1 = self.kd.weight_k[kpt1.k]
w2 = self.kd.weight_k[kpt2.k]
# Is k2 in the 1. BZ?
is_ibz2 = (self.kd.ibz2bz_k[kpt2.k] == K2)
e_n = self.calculate_interaction(n1_n, n2, kpt1, kpt2, q, K2,
eik20r_R, eik2r_R,
is_ibz2)
e_n *= 1.0 / self.kd.nbzkpts / self.wfs.nspins * self.qstride_c.prod()
if q == self.q0:
e_n[n1_n == n2] *= 0.5
f1_n = kpt1.f_n[n1_n]
eps1_n = kpt1.eps_n[n1_n]
f2 = kpt2.f_n[n2]
eps2 = kpt2.eps_n[n2]
s_n = np.sign(eps2 - eps1_n)
evv = (f1_n * f2 * e_n).sum()
evvacdf = 0.5 * (f1_n * (1 - s_n) * e_n +
f2 * (1 + s_n) * e_n).sum()
self.evv += evv * w1
self.evvacdf += evvacdf * w1
if is_ibz2:
self.evv += evv * w2
self.evvacdf += evvacdf * w2
if self.bandstructure:
x = self.wfs.nspins
self.exx_skn[kpt1.s, kpt1.k, n1_n] += x * f2 * e_n
if is_ibz2:
self.exx_skn[kpt2.s, kpt2.k, n2] += x * np.dot(f1_n, e_n)
def calculate_interaction(self, n1_n, n2, kpt1, kpt2, q, k,
eik20r_R, eik2r_R, is_ibz2):
"""Calculate Coulomb interactions.
For all n1 in the n1_n list, calculate interaction with n2."""
# number of plane waves:
ng1 = self.wfs.ng_k[kpt1.k]
ng2 = self.wfs.ng_k[kpt2.k]
# Transform to real space and apply symmetry operation:
self.timer.start('IFFT1')
if is_ibz2:
u2_R = self.pd.ifft(kpt2.psit_nG[n2, :ng2], kpt2.k)
else:
psit2_R = self.pd.ifft(kpt2.psit_nG[n2, :ng2], kpt2.k) * eik20r_R
self.timer.start('Symmetry transform')
u2_R = self.kd.transform_wave_function(psit2_R, k) / eik2r_R
self.timer.stop()
self.timer.stop()
# Calculate pair densities:
nt_nG = self.pd2.zeros(len(n1_n), q=q)
for n1, nt_G in zip(n1_n, nt_nG):
self.timer.start('IFFT2')
u1_R = self.pd.ifft(kpt1.psit_nG[n1, :ng1], kpt1.k)
self.timer.stop()
nt_R = u1_R.conj() * u2_R
self.timer.start('FFT')
nt_G[:] = self.pd2.fft(nt_R, q)
self.timer.stop()
s = self.kd.sym_k[k]
time_reversal = self.kd.time_reversal_k[k]
k2_c = self.kd.ibzk_kc[kpt2.k]
self.timer.start('Compensation charges')
Q_anL = {} # coefficients for shape functions
for a, P1_ni in kpt1.P_ani.items():
P1_ni = P1_ni[n1_n]
if is_ibz2:
P2_i = kpt2.P_ani[a][n2]
else:
b = self.kd.symmetry.a_sa[s, a]
S_c = (np.dot(self.spos_ac[a], self.kd.symmetry.op_scc[s]) -
self.spos_ac[b])
assert abs(S_c.round() - S_c).max() < 1e-5
if self.ghat.dtype == complex:
x = np.exp(2j * pi * np.dot(k2_c, S_c))
else:
x = 1.0
P2_i = np.dot(self.wfs.setups[a].R_sii[s],
kpt2.P_ani[b][n2]) * x
if time_reversal:
P2_i = P2_i.conj()
D_np = []
for P1_i in P1_ni:
D_ii = np.outer(P1_i.conj(), P2_i)
D_np.append(pack(D_ii))
Q_anL[a] = np.dot(D_np, self.wfs.setups[a].Delta_pL)
self.timer.start('Expand')
if q != self.qlatest:
self.f_IG = self.ghat.expand(q)
self.qlatest = q
self.timer.stop('Expand')
# Add compensation charges:
self.ghat.add(nt_nG, Q_anL, q, self.f_IG)
self.timer.stop('Compensation charges')
if self.molecule and n2 in n1_n:
nn = (n1_n == n2).nonzero()[0][0]
nt_nG[nn] -= self.ngauss_G
else:
nn = None
iG2_G = self.iG2_qG[q]
# Calculate energies:
e_n = np.empty(len(n1_n))
for n, nt_G in enumerate(nt_nG):
e_n[n] = -4 * pi * np.real(self.pd2.integrate(nt_G, nt_G * iG2_G))
self.npairs += 1
if nn is not None:
e_n[nn] -= 2 * (self.pd2.integrate(nt_nG[nn], self.vgauss_G) +
(self.beta / 2 / pi)**0.5)
if self.write_timing_information:
t = (time() - self.t0) / len(n1_n)
self.log('Time for first pair-density: %10.3f seconds' % t)
self.log('Estimated total time: %10.3f seconds' %
(t * self.npairs0 / self.world.size))
self.write_timing_information = False
return e_n
def calculate_exx_paw_correction(self):
self.timer.start('PAW correction')
self.devv = 0.0
self.evc = 0.0
self.ecc = 0.0
deg = 2 // self.wfs.nspins # spin degeneracy
for a, D_sp in self.dens.D_asp.items():
setup = self.wfs.setups[a]
for D_p in D_sp:
D_ii = unpack2(D_p)
ni = len(D_ii)
for i1 in range(ni):
for i2 in range(ni):
A = 0.0
for i3 in range(ni):
p13 = packed_index(i1, i3, ni)
for i4 in range(ni):
p24 = packed_index(i2, i4, ni)
A += setup.M_pp[p13, p24] * D_ii[i3, i4]
self.devv -= D_ii[i1, i2] * A / deg
self.evc -= np.dot(D_p, setup.X_p)
self.ecc += setup.ExxC
if not self.bandstructure:
self.timer.stop('PAW correction')
return
Q = self.world.size // self.wfs.kd.comm.size
self.exx_skn *= Q
for kpt in self.wfs.kpt_u:
for a, D_sp in self.dens.D_asp.items():
setup = self.wfs.setups[a]
for D_p in D_sp:
D_ii = unpack2(D_p)
ni = len(D_ii)
P_ni = kpt.P_ani[a]
for i1 in range(ni):
for i2 in range(ni):
A = 0.0
for i3 in range(ni):
p13 = packed_index(i1, i3, ni)
for i4 in range(ni):
p24 = packed_index(i2, i4, ni)
A += setup.M_pp[p13, p24] * D_ii[i3, i4]
self.exx_skn[kpt.s, kpt.k] -= \
(A * P_ni[:, i1].conj() * P_ni[:, i2]).real
p12 = packed_index(i1, i2, ni)
self.exx_skn[kpt.s, kpt.k] -= \
(P_ni[:, i1].conj() * setup.X_p[p12] *
P_ni[:, i2]).real / self.wfs.nspins
self.world.sum(self.exx_skn)
self.exx_skn *= self.hybrid / Q
self.timer.stop('PAW correction')
def initialize_gaussian(self):
"""Calculate gaussian compensation charge and its potential.
Used to decouple electrostatic interactions between
periodically repeated images for molecular calculations.
Charge containing one electron::
(beta/pi)^(3/2)*exp(-beta*r^2),
its Fourier transform::
exp(-G^2/(4*beta)),
and its potential::
erf(beta^0.5*r)/r.
"""
gd = self.wfs.gd
# Set exponent of exp-function to -19 on the boundary:
self.beta = 4 * 19 * (gd.icell_cv**2).sum(1).max()
# Calculate gaussian:
G_Gv = self.pd2.get_reciprocal_vectors()
G2_G = self.pd2.G2_qG[0]
C_v = gd.cell_cv.sum(0) / 2 # center of cell
self.ngauss_G = np.exp(-1.0 / (4 * self.beta) * G2_G +
1j * np.dot(G_Gv, C_v)) / gd.dv
# Calculate potential from gaussian:
R_Rv = gd.get_grid_point_coordinates().transpose((1, 2, 3, 0))
r_R = ((R_Rv - C_v)**2).sum(3)**0.5
if (gd.N_c % 2 == 0).all():
r_R[tuple(gd.N_c // 2)] = 1.0 # avoid dividing by zero
v_R = erf(self.beta**0.5 * r_R) / r_R
if (gd.N_c % 2 == 0).all():
v_R[tuple(gd.N_c // 2)] = (4 * self.beta / pi)**0.5
self.vgauss_G = self.pd2.fft(v_R)
# Compare self-interaction to analytic result:
assert abs(0.5 * self.pd2.integrate(self.ngauss_G, self.vgauss_G) -
(self.beta / 2 / pi)**0.5) < 1e-6
class TimeDependentHamiltonian():
def __init__(self, calc):
#initialization
self.calc = calc
self.wfs = calc.wfs
self.ham = calc.hamiltonian
self.den = calc.density
self.occ = calc.occupations
#initialization plane and grid descriptors from GPAW calculation
self.pd = calc.wfs.pd
self.gd = calc.wfs.gd
self.volume = np.abs(np.linalg.det(self.gd.cell_cv))
#number of k-points
self.nq = len(calc.wfs.kpt_u)
#number of bands
self.nbands = calc.get_number_of_bands()
#number of electrons
self.nelectrons = calc.get_number_of_electrons()
#kinetic operator
self.kinetic = np.zeros((self.nq, self.nbands, self.nbands),
dtype=complex)
#overlap operator
self.overlap = np.zeros((self.nq, self.nbands, self.nbands),
dtype=complex)
#local momentum operator
self.local_moment = np.zeros((3, self.nq, self.nbands, self.nbands),
dtype=complex)
#nonlocal momentum operator
self.nonlocal_moment = np.zeros((3, self.nq, self.nbands, self.nbands),
dtype=complex)
#Fermi-Dirac occupation
self.f_n = np.zeros((self.nq, self.nbands), dtype=float)
#ground state Kohn-Sham orbitals wavefunctions
psi_gs = []
#ground state Kohn-Sham orbitals density
den_gs = []
for kpt in self.wfs.kpt_u:
self.overlap[kpt.q] = np.eye(self.nbands)
self.f_n[kpt.q] = kpt.f_n
kinetic = 0.5 * self.pd.G2_qG[kpt.q] # |G+q|^2/2
gradient = self.pd.get_reciprocal_vectors(kpt.q)
psi = []
den = []
for n in range(self.nbands):
psi.append(self.pd.ifft(kpt.psit_nG[n], kpt.q))
den.append(np.abs(psi[-1])**2)
for m in range(self.nbands):
self.kinetic[kpt.q, n, m] = self.pd.integrate(
kpt.psit_nG[n], kinetic * kpt.psit_nG[m])
#calculation local momentum
#<psi_qn|\nabla|psi_qm>
for i in range(3):
self.local_moment[i, kpt.q, n, m] = self.pd.integrate(
kpt.psit_nG[n], gradient[:, i] * kpt.psit_nG[m])
psi_gs.append(psi)
den_gs.append(den)
self.psi_gs = np.array(psi_gs)
self.den_gs = np.array(den_gs, dtype=float)
#real space grid points
self.r = self.gd.get_grid_point_coordinates()
#initialization local and nonlocal part of pseudopotential
self.init_potential()
self.proj = np.zeros((self.nq, self.nbands, self.norb), dtype=complex)
self.proj_r = np.zeros((3, self.nq, self.nbands, self.norb),
dtype=complex)
self.density = self.den.nt_sG.copy()
#initialization charge density (ion+electrons) for Hartree potential
self.ion_density = calc.hamiltonian.poisson.pd.ifft(
calc.density.rhot_q) - calc.density.nt_sg[0]
#plane wave descriptor for Hartree potential
self.pd0 = self.ham.poisson.pd
#reciprocal |G|^2 vectors for Hartree potential V(G)=4pi/|G|^2
self.G2 = self.ham.poisson.G2_q
self.G = self.pd0.get_reciprocal_vectors()
#fine to coarse and coarse to fine grids transformers (for correct calculation local potential)
self.fine_to_coarse = Transformer(calc.density.finegd, calc.density.gd,
3)
self.coarse_to_fine = Transformer(calc.density.gd, calc.density.finegd,
3)
#initialization local potenital from ground state density
self.update_local_potential()
self.update_gauge([0, 0, 0])
#----------------------------------------------------------------------------------------------------
def init_potential(self):
#initialization of nonlocal part of pseudopotential
# V_NL=|chi_i> V_i <chi_i|
spline_aj = []
for setup in self.wfs.setups:
spline_aj.append(setup.pt_j)
self.lfc = PWLFC(spline_aj, self.pd)
self.lfc.set_positions(self.calc.spos_ac) #set position of atoms
proj_G = []
proj_r = [] #collect chi_i in real space using FFT
for kpt in self.wfs.kpt_u:
proj_G.append(self.lfc.expand(kpt.q))
proj = []
n_i = proj_G[-1].shape[1]
for i in range(n_i):
proj.append(self.pd.ifft(proj_G[-1][:, i].copy(), kpt.q))
proj_r.append(proj)
self.chi = np.array(proj_r) / self.gd.dv
s = 0 # s=0 because we perform spin-paired calculation
V = [] #collect V
for a in range(len(self.wfs.setups)):
dH_ii = unpack(self.ham.dH_asp[a][s])
V.append(dH_ii.diagonal())
V = np.array(V)
self.V = V.ravel()
self.norb = self.V.size # number of orbitals in nonlocal potential
#initialization of local part of pseudopotential
V = self.ham.vbar.pd.zeros()
self.ham.vbar.add(V)
self.Vloc = self.ham.vbar.pd.ifft(V)
#----------------------------------------------------------------------------------------------------
def update_density(self, wfn):
self.density[0] = np.zeros_like(self.density[0])
fast_density(self.density[0], wfn, self.den_gs)
self.occupation = np.sum(np.abs(wfn)**2, axis=2)
self.update_local_potential()
#----------------------------------------------------------------------------------------------------
def update_gauge(self, A):
#update projections p_qno=<chi_qo|psi_qn>
phase = np.exp(1j * np.einsum('ixyz,i->xyz', self.r, A))
fast_projections(self.proj, self.chi, phase, self.psi_gs, self.gd.dv)
#update interaction hamiltonian
#H_I=\nabla*A+0.5*A^2
self.interaction = np.einsum(
'i,iqnm->qnm', A,
self.local_moment) + 0.5 * np.linalg.norm(A)**2 * self.overlap
#calculation nonlocal momentum operator
# I_NL=-i[r,V_NL]=-i sum_o V_o (r|chi_o><chi_o - |chi_o><chi_o|r)
for i in range(3):
fast_projections(self.proj_r[0], self.chi, self.r[i] * phase,
self.psi_gs, self.gd.dv)
self.nonlocal_moment = -1j * (np.einsum(
'o,iqno,qmo->iqnm', self.V, self.proj_r.conj(), self.proj) -
np.einsum('o,qno,iqmo->iqnm', self.V,
self.proj.conj(), self.proj_r))
self.moment = self.local_moment + self.nonlocal_moment
#----------------------------------------------------------------------------------------------------
def update_local_potential(self):
#tranform density from coarse to fine grids
density = self.coarse_to_fine.apply(self.density.copy())
#calculate XC potential
VXC = np.zeros_like(density)
self.ham.xc.calculate(self.pd0.gd, density, VXC)
# calculate Hartree potential
charge_density = density + self.ion_density
VH = 4 * np.pi * self.pd0.fft(charge_density) / self.G2
VH = self.pd0.ifft(VH)
#transform Hartree and XC potential from fine to coarse grids
self.VXC = self.fine_to_coarse.apply(VXC[0])
self.VH = self.fine_to_coarse.apply(VH)
#----------------------------------------------------------------------------------------------------
def calculate_nonlocal(self):
#calculation nonlocal part of Hamiltonian
return np.einsum('o,qno,qmo->qnm', self.V, self.proj.conj(), self.proj)
#----------------------------------------------------------------------------------------------------
def calculate_local(self):
#calculation local part of Hamiltonian
local = np.zeros((self.nq, self.nbands, self.nbands), dtype=complex)
return fast_local(local, self.Vloc + self.VXC + self.VH, self.psi_gs,
self.gd.dv)
#----------------------------------------------------------------------------------------------------
def calculate_kinetic(self):
#calculation kinetic part of Hamiltonian
return self.kinetic
#----------------------------------------------------------------------------------------------------
def hamiltonian(self):
#calculation hamiltonian
return self.calculate_kinetic() + self.calculate_local(
) + self.calculate_nonlocal() + self.interaction
#----------------------------------------------------------------------------------------------------
def calculate_current(self, wfn):
return np.einsum('iqnm,qne,qme->i', self.moment, wfn.conj(),
wfn) / self.volume / self.nq
for l in range(4):
print(l)
s = Spline(l, rc, 2 * x**1.5 / np.pi * np.exp(-x * r**2))
lfc = PWLFC([[s]], pd)
lfcr = PWLFC([[s]], pdr)
c_axi = {0: np.zeros((1, 2 * l + 1), complex)}
c_axi[0][0, 0] = 1.9
cr_axi = {0: np.zeros((1, 2 * l + 1))}
cr_axi[0][0, 0] = 1.9
b = pd.zeros(1, dtype=complex)
br = pdr.zeros(1)
lfc.set_positions(spos_ac)
lfc.add(b, c_axi)
lfcr.set_positions(spos_ac)
lfcr.add(br, cr_axi)
a = pd.ifft(b)
ar = pdr.ifft(br)
equal(abs(a-ar).max(), 0, 1e-14)
if l == 0:
a = a[:, ::-1].copy()
b0 = pd.fft(a)
br0 = pdr.fft(a.real)
lfc.integrate(b0, c_axi)
lfcr.integrate(br0, cr_axi)
class HybridXC(HybridXCBase):
orbital_dependent = True
def __init__(self,
name,
hybrid=None,
xc=None,
alpha=None,
gamma_point=1,
method='standard',
bandstructure=False,
logfilename='-',
bands=None,
fcut=1e-10,
molecule=False,
qstride=1,
world=None):
"""Mix standard functionals with exact exchange.
name: str
Name of functional: EXX, PBE0, HSE03, HSE06
hybrid: float
Fraction of exact exchange.
xc: str or XCFunctional object
Standard DFT functional with scaled down exchange.
method: str
Use 'standard' standard formula and 'acdf for
adiabatic-connection dissipation fluctuation formula.
alpha: float
XXX describe
gamma_point: bool
0: Skip k2-k1=0 interactions.
1: Use the alpha method.
2: Integrate the gamma point.
bandstructure: bool
Calculate bandstructure instead of just the total energy.
bands: list of int
List of bands to calculate bandstructure for. Default is
all bands.
molecule: bool
Decouple electrostatic interactions between periodically
repeated images.
fcut: float
Threshold for empty band.
"""
self.alpha = alpha
self.fcut = fcut
self.gamma_point = gamma_point
self.method = method
self.bandstructure = bandstructure
self.bands = bands
self.fd = logfilename
self.write_timing_information = True
HybridXCBase.__init__(self, name, hybrid, xc)
# EXX energies:
self.exx = None # total
self.evv = None # valence-valence (pseudo part)
self.evvacdf = None # valence-valence (pseudo part)
self.devv = None # valence-valence (PAW correction)
self.evc = None # valence-core
self.ecc = None # core-core
self.exx_skn = None # bandstructure
self.qlatest = None
if world is None:
world = mpi.world
self.world = world
self.molecule = molecule
if isinstance(qstride, int):
qstride = [qstride] * 3
self.qstride_c = np.asarray(qstride)
self.timer = Timer()
def log(self, *args, **kwargs):
prnt(file=self.fd, *args, **kwargs)
self.fd.flush()
def calculate_radial(self,
rgd,
n_sLg,
Y_L,
v_sg,
dndr_sLg=None,
rnablaY_Lv=None,
tau_sg=None,
dedtau_sg=None):
return self.xc.calculate_radial(rgd, n_sLg, Y_L, v_sg, dndr_sLg,
rnablaY_Lv)
def calculate_paw_correction(self,
setup,
D_sp,
dEdD_sp=None,
addcoredensity=True,
a=None):
return self.xc.calculate_paw_correction(setup, D_sp, dEdD_sp,
addcoredensity, a)
def initialize(self, dens, ham, wfs, occupations):
assert wfs.bd.comm.size == 1
self.xc.initialize(dens, ham, wfs, occupations)
self.dens = dens
self.wfs = wfs
# Make a k-point descriptor that is not distributed
# (self.kd.comm is serial_comm):
self.kd = wfs.kd.copy()
self.fd = logfile(self.fd, self.world.rank)
wfs.initialize_wave_functions_from_restart_file()
def set_positions(self, spos_ac):
self.spos_ac = spos_ac
def calculate(self, gd, n_sg, v_sg=None, e_g=None):
# Normal XC contribution:
exc = self.xc.calculate(gd, n_sg, v_sg, e_g)
# Add EXX contribution:
return exc + self.exx * self.hybrid
def calculate_exx(self):
"""Non-selfconsistent calculation."""
self.timer.start('EXX')
self.timer.start('Initialization')
kd = self.kd
wfs = self.wfs
if fftw.FFTPlan is fftw.NumpyFFTPlan:
self.log('NOT USING FFTW !!')
self.log('Spins:', self.wfs.nspins)
W = max(1, self.wfs.kd.comm.size // self.wfs.nspins)
# Are the k-points distributed?
kparallel = (W > 1)
# Find number of occupied bands:
self.nocc_sk = np.zeros((self.wfs.nspins, kd.nibzkpts), int)
for kpt in self.wfs.kpt_u:
for n, f in enumerate(kpt.f_n):
if abs(f) < self.fcut:
self.nocc_sk[kpt.s, kpt.k] = n
break
else:
self.nocc_sk[kpt.s, kpt.k] = self.wfs.bd.nbands
self.wfs.kd.comm.sum(self.nocc_sk)
noccmin = self.nocc_sk.min()
noccmax = self.nocc_sk.max()
self.log('Number of occupied bands (min, max): %d, %d' %
(noccmin, noccmax))
self.log('Number of valence electrons:', self.wfs.setups.nvalence)
if self.bandstructure:
self.log('Calculating eigenvalue shifts.')
# allocate array for eigenvalue shifts:
self.exx_skn = np.zeros(
(self.wfs.nspins, kd.nibzkpts, self.wfs.bd.nbands))
if self.bands is None:
noccmax = self.wfs.bd.nbands
else:
noccmax = max(max(self.bands) + 1, noccmax)
N_c = self.kd.N_c
vol = wfs.gd.dv * wfs.gd.N_c.prod()
if self.alpha is None:
alpha = 6 * vol**(2 / 3.0) / pi**2
else:
alpha = self.alpha
if self.gamma_point == 1:
if alpha == 0.0:
qvol = (2 * np.pi)**3 / vol / N_c.prod()
self.gamma = 4 * np.pi * (3 * qvol /
(4 * np.pi))**(1 / 3.) / qvol
else:
self.gamma = self.calculate_gamma(vol, alpha)
else:
kcell_cv = wfs.gd.cell_cv.copy()
kcell_cv[0] *= N_c[0]
kcell_cv[1] *= N_c[1]
kcell_cv[2] *= N_c[2]
self.gamma = madelung(kcell_cv) * vol * N_c.prod() / (4 * np.pi)
self.log('Value of alpha parameter: %.3f Bohr^2' % alpha)
self.log('Value of gamma parameter: %.3f Bohr^2' % self.gamma)
# Construct all possible q=k2-k1 vectors:
Nq_c = (N_c - 1) // self.qstride_c
i_qc = np.indices(Nq_c * 2 + 1, float).transpose((1, 2, 3, 0)).reshape(
(-1, 3))
self.bzq_qc = (i_qc - Nq_c) / N_c * self.qstride_c
self.q0 = ((Nq_c * 2 + 1).prod() - 1) // 2 # index of q=(0,0,0)
assert not self.bzq_qc[self.q0].any()
# Count number of pairs for each q-vector:
self.npairs_q = np.zeros(len(self.bzq_qc), int)
for s in range(kd.nspins):
for k1 in range(kd.nibzkpts):
for k2 in range(kd.nibzkpts):
for K2, q, n1_n, n2 in self.indices(s, k1, k2):
self.npairs_q[q] += len(n1_n)
self.npairs0 = self.npairs_q.sum() # total number of pairs
self.log('Number of pairs:', self.npairs0)
# Distribute q-vectors to Q processors:
Q = self.world.size // self.wfs.kd.comm.size
myrank = self.world.rank // self.wfs.kd.comm.size
rank = 0
N = 0
myq = []
nq = 0
for q, n in enumerate(self.npairs_q):
if n > 0:
nq += 1
if rank == myrank:
myq.append(q)
N += n
if N >= (rank + 1.0) * self.npairs0 / Q:
rank += 1
assert len(myq) > 0, 'Too few q-vectors for too many processes!'
self.bzq_qc = self.bzq_qc[myq]
try:
self.q0 = myq.index(self.q0)
except ValueError:
self.q0 = None
self.log('%d x %d x %d k-points' % tuple(self.kd.N_c))
self.log('Distributing %d IBZ k-points over %d process(es).' %
(kd.nibzkpts, self.wfs.kd.comm.size))
self.log('Distributing %d q-vectors over %d process(es).' % (nq, Q))
# q-point descriptor for my q-vectors:
qd = KPointDescriptor(self.bzq_qc)
# Plane-wave descriptor for all wave-functions:
self.pd = PWDescriptor(wfs.pd.ecut, wfs.gd, dtype=wfs.pd.dtype, kd=kd)
# Plane-wave descriptor pair-densities:
self.pd2 = PWDescriptor(self.dens.pd2.ecut,
self.dens.gd,
dtype=wfs.dtype,
kd=qd)
self.log('Cutoff energies:')
self.log(' Wave functions: %10.3f eV' %
(self.pd.ecut * Hartree))
self.log(' Density: %10.3f eV' %
(self.pd2.ecut * Hartree))
# Calculate 1/|G+q|^2 with special treatment of |G+q|=0:
G2_qG = self.pd2.G2_qG
if self.q0 is None:
if self.omega is None:
self.iG2_qG = [1.0 / G2_G for G2_G in G2_qG]
else:
self.iG2_qG = [
(1.0 / G2_G * (1 - np.exp(-G2_G / (4 * self.omega**2))))
for G2_G in G2_qG
]
else:
G2_qG[self.q0][0] = 117.0 # avoid division by zero
if self.omega is None:
self.iG2_qG = [1.0 / G2_G for G2_G in G2_qG]
self.iG2_qG[self.q0][0] = self.gamma
else:
self.iG2_qG = [
(1.0 / G2_G * (1 - np.exp(-G2_G / (4 * self.omega**2))))
for G2_G in G2_qG
]
self.iG2_qG[self.q0][0] = 1 / (4 * self.omega**2)
G2_qG[self.q0][0] = 0.0 # restore correct value
# Compensation charges:
self.ghat = PWLFC([setup.ghat_l for setup in wfs.setups], self.pd2)
self.ghat.set_positions(self.spos_ac)
if self.molecule:
self.initialize_gaussian()
self.log('Value of beta parameter: %.3f 1/Bohr^2' % self.beta)
self.timer.stop('Initialization')
# Ready ... set ... go:
self.t0 = time()
self.npairs = 0
self.evv = 0.0
self.evvacdf = 0.0
for s in range(self.wfs.nspins):
kpt1_q = [
KPoint(self.wfs, noccmax).initialize(kpt)
for kpt in self.wfs.kpt_u if kpt.s == s
]
kpt2_q = kpt1_q[:]
if len(kpt1_q) == 0:
# No s-spins on this CPU:
continue
# Send and receive ranks:
srank = self.wfs.kd.get_rank_and_index(s, (kpt1_q[0].k - 1) %
kd.nibzkpts)[0]
rrank = self.wfs.kd.get_rank_and_index(s, (kpt1_q[-1].k + 1) %
kd.nibzkpts)[0]
# Shift k-points kd.nibzkpts - 1 times:
for i in range(kd.nibzkpts):
if i < kd.nibzkpts - 1:
if kparallel:
kpt = kpt2_q[-1].next(self.wfs)
kpt.start_receiving(rrank)
kpt2_q[0].start_sending(srank)
else:
kpt = kpt2_q[0]
self.timer.start('Calculate')
for kpt1, kpt2 in zip(kpt1_q, kpt2_q):
# Loop over all k-points that k2 can be mapped to:
for K2, q, n1_n, n2 in self.indices(s, kpt1.k, kpt2.k):
self.apply(K2, q, kpt1, kpt2, n1_n, n2)
self.timer.stop('Calculate')
if i < kd.nibzkpts - 1:
self.timer.start('Wait')
if kparallel:
kpt.wait()
kpt2_q[0].wait()
self.timer.stop('Wait')
kpt2_q.pop(0)
kpt2_q.append(kpt)
self.evv = self.world.sum(self.evv)
self.evvacdf = self.world.sum(self.evvacdf)
self.calculate_exx_paw_correction()
if self.method == 'standard':
self.exx = self.evv + self.devv + self.evc + self.ecc
elif self.method == 'acdf':
self.exx = self.evvacdf + self.devv + self.evc + self.ecc
else:
1 / 0
self.log('Exact exchange energy:')
for txt, e in [('core-core', self.ecc), ('valence-core', self.evc),
('valence-valence (pseudo, acdf)', self.evvacdf),
('valence-valence (pseudo, standard)', self.evv),
('valence-valence (correction)', self.devv),
('total (%s)' % self.method, self.exx)]:
self.log(' %-36s %14.6f eV' % (txt + ':', e * Hartree))
self.log('Total time: %10.3f seconds' % (time() - self.t0))
self.npairs = self.world.sum(self.npairs)
assert self.npairs == self.npairs0
self.timer.stop('EXX')
self.timer.write(self.fd)
def calculate_gamma(self, vol, alpha):
if self.molecule:
return 0.0
N_c = self.kd.N_c
offset_c = (N_c + 1) % 2 * 0.5 / N_c
bzq_qc = monkhorst_pack(N_c) + offset_c
qd = KPointDescriptor(bzq_qc)
pd = PWDescriptor(self.wfs.pd.ecut, self.wfs.gd, kd=qd)
gamma = (vol / (2 * pi)**2 * sqrt(pi / alpha) * self.kd.nbzkpts)
for G2_G in pd.G2_qG:
if G2_G[0] < 1e-7:
G2_G = G2_G[1:]
gamma -= np.dot(np.exp(-alpha * G2_G), G2_G**-1)
return gamma / self.qstride_c.prod()
def indices(self, s, k1, k2):
"""Generator for (K2, q, n1, n2) indices for (k1, k2) pair.
s: int
Spin index.
k1: int
Index of k-point in the IBZ.
k2: int
Index of k-point in the IBZ.
Returns (K, q, n1_n, n2), where K then index of the k-point in
the BZ that k2 is mapped to, q is the index of the q-vector
between K and k1, and n1_n is a list of bands that should be
combined with band n2."""
for K, k in enumerate(self.kd.bz2ibz_k):
if k == k2:
for K, q, n1_n, n2 in self._indices(s, k1, k2, K):
yield K, q, n1_n, n2
def _indices(self, s, k1, k2, K2):
k1_c = self.kd.ibzk_kc[k1]
k2_c = self.kd.bzk_kc[K2]
q_c = k2_c - k1_c
q = abs(self.bzq_qc - q_c).sum(1).argmin()
if abs(self.bzq_qc[q] - q_c).sum() > 1e-7:
return
if self.gamma_point == 0 and q == self.q0:
return
nocc1 = self.nocc_sk[s, k1]
nocc2 = self.nocc_sk[s, k2]
# Is k2 in the IBZ?
is_ibz2 = (self.kd.ibz2bz_k[k2] == K2)
for n2 in range(self.wfs.bd.nbands):
# Find range of n1's (from n1a to n1b-1):
if is_ibz2:
# We get this combination twice, so let's only do half:
if k1 >= k2:
n1a = n2
else:
n1a = n2 + 1
else:
n1a = 0
n1b = self.wfs.bd.nbands
if self.bandstructure:
if n2 >= nocc2:
n1b = min(n1b, nocc1)
else:
if n2 >= nocc2:
break
n1b = min(n1b, nocc1)
if self.bands is not None:
assert self.bandstructure
n1_n = []
for n1 in range(n1a, n1b):
if (n1 in self.bands and n2 < nocc2
or is_ibz2 and n2 in self.bands and n1 < nocc1):
n1_n.append(n1)
n1_n = np.array(n1_n)
else:
n1_n = np.arange(n1a, n1b)
if len(n1_n) == 0:
continue
yield K2, q, n1_n, n2
def apply(self, K2, q, kpt1, kpt2, n1_n, n2):
k20_c = self.kd.ibzk_kc[kpt2.k]
k2_c = self.kd.bzk_kc[K2]
if k2_c.any():
self.timer.start('Initialize plane waves')
eik2r_R = self.wfs.gd.plane_wave(k2_c)
eik20r_R = self.wfs.gd.plane_wave(k20_c)
self.timer.stop('Initialize plane waves')
else:
eik2r_R = 1.0
eik20r_R = 1.0
w1 = self.kd.weight_k[kpt1.k]
w2 = self.kd.weight_k[kpt2.k]
# Is k2 in the 1. BZ?
is_ibz2 = (self.kd.ibz2bz_k[kpt2.k] == K2)
e_n = self.calculate_interaction(n1_n, n2, kpt1, kpt2, q, K2, eik20r_R,
eik2r_R, is_ibz2)
e_n *= 1.0 / self.kd.nbzkpts / self.wfs.nspins * self.qstride_c.prod()
if q == self.q0:
e_n[n1_n == n2] *= 0.5
f1_n = kpt1.f_n[n1_n]
eps1_n = kpt1.eps_n[n1_n]
f2 = kpt2.f_n[n2]
eps2 = kpt2.eps_n[n2]
s_n = np.sign(eps2 - eps1_n)
evv = (f1_n * f2 * e_n).sum()
evvacdf = 0.5 * (f1_n * (1 - s_n) * e_n + f2 * (1 + s_n) * e_n).sum()
self.evv += evv * w1
self.evvacdf += evvacdf * w1
if is_ibz2:
self.evv += evv * w2
self.evvacdf += evvacdf * w2
if self.bandstructure:
x = self.wfs.nspins
self.exx_skn[kpt1.s, kpt1.k, n1_n] += x * f2 * e_n
if is_ibz2:
self.exx_skn[kpt2.s, kpt2.k, n2] += x * np.dot(f1_n, e_n)
def calculate_interaction(self, n1_n, n2, kpt1, kpt2, q, k, eik20r_R,
eik2r_R, is_ibz2):
"""Calculate Coulomb interactions.
For all n1 in the n1_n list, calculate interaction with n2."""
# number of plane waves:
ng1 = self.wfs.ng_k[kpt1.k]
ng2 = self.wfs.ng_k[kpt2.k]
# Transform to real space and apply symmetry operation:
self.timer.start('IFFT1')
if is_ibz2:
u2_R = self.pd.ifft(kpt2.psit_nG[n2, :ng2], kpt2.k)
else:
psit2_R = self.pd.ifft(kpt2.psit_nG[n2, :ng2], kpt2.k) * eik20r_R
self.timer.start('Symmetry transform')
u2_R = self.kd.transform_wave_function(psit2_R, k) / eik2r_R
self.timer.stop()
self.timer.stop()
# Calculate pair densities:
nt_nG = self.pd2.zeros(len(n1_n), q=q)
for n1, nt_G in zip(n1_n, nt_nG):
self.timer.start('IFFT2')
u1_R = self.pd.ifft(kpt1.psit_nG[n1, :ng1], kpt1.k)
self.timer.stop()
nt_R = u1_R.conj() * u2_R
self.timer.start('FFT')
nt_G[:] = self.pd2.fft(nt_R, q)
self.timer.stop()
s = self.kd.sym_k[k]
time_reversal = self.kd.time_reversal_k[k]
k2_c = self.kd.ibzk_kc[kpt2.k]
self.timer.start('Compensation charges')
Q_anL = {} # coefficients for shape functions
for a, P1_ni in kpt1.P_ani.items():
P1_ni = P1_ni[n1_n]
if is_ibz2:
P2_i = kpt2.P_ani[a][n2]
else:
b = self.kd.symmetry.a_sa[s, a]
S_c = (np.dot(self.spos_ac[a], self.kd.symmetry.op_scc[s]) -
self.spos_ac[b])
assert abs(S_c.round() - S_c).max() < 1e-5
if self.ghat.dtype == complex:
x = np.exp(2j * pi * np.dot(k2_c, S_c))
else:
x = 1.0
P2_i = np.dot(self.wfs.setups[a].R_sii[s],
kpt2.P_ani[b][n2]) * x
if time_reversal:
P2_i = P2_i.conj()
D_np = []
for P1_i in P1_ni:
D_ii = np.outer(P1_i.conj(), P2_i)
D_np.append(pack(D_ii))
Q_anL[a] = np.dot(D_np, self.wfs.setups[a].Delta_pL)
self.timer.start('Expand')
if q != self.qlatest:
self.f_IG = self.ghat.expand(q)
self.qlatest = q
self.timer.stop('Expand')
# Add compensation charges:
self.ghat.add(nt_nG, Q_anL, q, self.f_IG)
self.timer.stop('Compensation charges')
if self.molecule and n2 in n1_n:
nn = (n1_n == n2).nonzero()[0][0]
nt_nG[nn] -= self.ngauss_G
else:
nn = None
iG2_G = self.iG2_qG[q]
# Calculate energies:
e_n = np.empty(len(n1_n))
for n, nt_G in enumerate(nt_nG):
e_n[n] = -4 * pi * np.real(self.pd2.integrate(nt_G, nt_G * iG2_G))
self.npairs += 1
if nn is not None:
e_n[nn] -= 2 * (self.pd2.integrate(nt_nG[nn], self.vgauss_G) +
(self.beta / 2 / pi)**0.5)
if self.write_timing_information:
t = (time() - self.t0) / len(n1_n)
self.log('Time for first pair-density: %10.3f seconds' % t)
self.log('Estimated total time: %10.3f seconds' %
(t * self.npairs0 / self.world.size))
self.write_timing_information = False
return e_n
def calculate_exx_paw_correction(self):
self.timer.start('PAW correction')
self.devv = 0.0
self.evc = 0.0
self.ecc = 0.0
deg = 2 // self.wfs.nspins # spin degeneracy
for a, D_sp in self.dens.D_asp.items():
setup = self.wfs.setups[a]
for D_p in D_sp:
D_ii = unpack2(D_p)
ni = len(D_ii)
for i1 in range(ni):
for i2 in range(ni):
A = 0.0
for i3 in range(ni):
p13 = packed_index(i1, i3, ni)
for i4 in range(ni):
p24 = packed_index(i2, i4, ni)
A += setup.M_pp[p13, p24] * D_ii[i3, i4]
self.devv -= D_ii[i1, i2] * A / deg
self.evc -= np.dot(D_p, setup.X_p)
self.ecc += setup.ExxC
if not self.bandstructure:
self.timer.stop('PAW correction')
return
Q = self.world.size // self.wfs.kd.comm.size
self.exx_skn *= Q
for kpt in self.wfs.kpt_u:
for a, D_sp in self.dens.D_asp.items():
setup = self.wfs.setups[a]
for D_p in D_sp:
D_ii = unpack2(D_p)
ni = len(D_ii)
P_ni = kpt.P_ani[a]
for i1 in range(ni):
for i2 in range(ni):
A = 0.0
for i3 in range(ni):
p13 = packed_index(i1, i3, ni)
for i4 in range(ni):
p24 = packed_index(i2, i4, ni)
A += setup.M_pp[p13, p24] * D_ii[i3, i4]
self.exx_skn[kpt.s, kpt.k] -= \
(A * P_ni[:, i1].conj() * P_ni[:, i2]).real
p12 = packed_index(i1, i2, ni)
self.exx_skn[kpt.s, kpt.k] -= \
(P_ni[:, i1].conj() * setup.X_p[p12] *
P_ni[:, i2]).real / self.wfs.nspins
self.world.sum(self.exx_skn)
self.exx_skn *= self.hybrid / Q
self.timer.stop('PAW correction')
def initialize_gaussian(self):
"""Calculate gaussian compensation charge and its potential.
Used to decouple electrostatic interactions between
periodically repeated images for molecular calculations.
Charge containing one electron::
(beta/pi)^(3/2)*exp(-beta*r^2),
its Fourier transform::
exp(-G^2/(4*beta)),
and its potential::
erf(beta^0.5*r)/r.
"""
gd = self.wfs.gd
# Set exponent of exp-function to -19 on the boundary:
self.beta = 4 * 19 * (gd.icell_cv**2).sum(1).max()
# Calculate gaussian:
G_Gv = self.pd2.get_reciprocal_vectors()
G2_G = self.pd2.G2_qG[0]
C_v = gd.cell_cv.sum(0) / 2 # center of cell
self.ngauss_G = np.exp(-1.0 / (4 * self.beta) * G2_G +
1j * np.dot(G_Gv, C_v)) / gd.dv
# Calculate potential from gaussian:
R_Rv = gd.get_grid_point_coordinates().transpose((1, 2, 3, 0))
r_R = ((R_Rv - C_v)**2).sum(3)**0.5
if (gd.N_c % 2 == 0).all():
r_R[tuple(gd.N_c // 2)] = 1.0 # avoid dividing by zero
v_R = erf(self.beta**0.5 * r_R) / r_R
if (gd.N_c % 2 == 0).all():
v_R[tuple(gd.N_c // 2)] = (4 * self.beta / pi)**0.5
self.vgauss_G = self.pd2.fft(v_R)
# Compare self-interaction to analytic result:
assert abs(0.5 * self.pd2.integrate(self.ngauss_G, self.vgauss_G) -
(self.beta / 2 / pi)**0.5) < 1e-6
for l in range(4):
print(l)
s = Spline(l, rc, 2 * x**1.5 / np.pi * np.exp(-x * r**2))
lfc = PWLFC([[s]], pd)
lfcr = PWLFC([[s]], pdr)
c_axi = {0: np.zeros((1, 2 * l + 1), complex)}
c_axi[0][0, 0] = 1.9
cr_axi = {0: np.zeros((1, 2 * l + 1))}
cr_axi[0][0, 0] = 1.9
b = pd.zeros(1, dtype=complex)
br = pdr.zeros(1)
lfc.set_positions(spos_ac)
lfc.add(b, c_axi)
lfcr.set_positions(spos_ac)
lfcr.add(br, cr_axi)
a = pd.ifft(b)
ar = pdr.ifft(br)
equal(abs(a-ar).max(), 0, 1e-14)
if l == 0:
a = a[:, ::-1].copy()
b0 = pd.fft(a)
br0 = pdr.fft(a.real)
lfc.integrate(b0, c_axi)
lfcr.integrate(br0, cr_axi)