def calculate(self, ecut, nbands=None, spin=False):
"""Calculate RPA correlation energy for one or several cutoffs.
ecut: float or list of floats
Plane-wave cutoff(s).
nbands: int
Number of bands (defaults to number of plane-waves).
spin: bool
Separate spin in response function.
(Only needed for beyond RPA methods that inherit this function).
"""
p = functools.partial(print, file=self.fd)
if isinstance(ecut, (float, int)):
ecut = ecut * (1 + 0.5 * np.arange(6))**(-2 / 3)
self.ecut_i = np.asarray(np.sort(ecut)) / Hartree
ecutmax = max(self.ecut_i)
if nbands is None:
p('Response function bands : Equal to number of plane waves')
else:
p('Response function bands : %s' % nbands)
p('Plane wave cutoffs (eV) :', end='')
for e in self.ecut_i:
p(' {0:.3f}'.format(e * Hartree), end='')
p()
if self.truncation is not None:
p('Using %s Coulomb truncation' % self.truncation)
p()
if self.filename and os.path.isfile(self.filename):
self.read()
self.world.barrier()
chi0 = Chi0(self.calc, 1j * Hartree * self.omega_w, eta=0.0,
intraband=False, hilbert=False,
txt='chi0.txt', timer=self.timer, world=self.world,
nblocks=self.nblocks)
self.blockcomm = chi0.blockcomm
wfs = self.calc.wfs
if self.truncation == 'wigner-seitz':
self.wstc = WignerSeitzTruncatedCoulomb(wfs.gd.cell_cv,
wfs.kd.N_c, self.fd)
else:
self.wstc = None
nq = len(self.energy_qi)
nw = len(self.omega_w)
nGmax = max(count_reciprocal_vectors(ecutmax, wfs.gd, q_c)
for q_c in self.ibzq_qc[nq:])
mynGmax = (nGmax + self.nblocks - 1) // self.nblocks
nx = (1 + spin) * nw * mynGmax * nGmax
A1_x = np.empty(nx, complex)
if self.nblocks > 1:
A2_x = np.empty(nx, complex)
else:
A2_x = None
self.timer.start('RPA')
for q_c in self.ibzq_qc[nq:]:
if np.allclose(q_c, 0.0) and self.skip_gamma:
self.energy_qi.append(len(self.ecut_i) * [0.0])
self.write()
p('Not calculating E_c(q) at Gamma')
p()
continue
thisqd = KPointDescriptor([q_c])
pd = PWDescriptor(ecutmax, wfs.gd, complex, thisqd)
nG = pd.ngmax
mynG = (nG + self.nblocks - 1) // self.nblocks
chi0.Ga = self.blockcomm.rank * mynG
chi0.Gb = min(chi0.Ga + mynG, nG)
shape = (1 + spin, nw, chi0.Gb - chi0.Ga, nG)
chi0_swGG = A1_x[:np.prod(shape)].reshape(shape)
chi0_swGG[:] = 0.0
if np.allclose(q_c, 0.0):
chi0_swxvG = np.zeros((1 + spin, nw, 2, 3, nG), complex)
chi0_swvv = np.zeros((1 + spin, nw, 3, 3), complex)
else:
chi0_swxvG = None
chi0_swvv = None
# First not completely filled band:
m1 = chi0.nocc1
p('# %s - %s' % (len(self.energy_qi), ctime().split()[-2]))
p('q = [%1.3f %1.3f %1.3f]' % tuple(q_c))
energy_i = []
for ecut in self.ecut_i:
if ecut == ecutmax:
# Nothing to cut away:
cut_G = None
m2 = nbands or nG
else:
cut_G = np.arange(nG)[pd.G2_qG[0] <= 2 * ecut]
m2 = len(cut_G)
p('E_cut = %d eV / Bands = %d:' % (ecut * Hartree, m2))
self.fd.flush()
energy = self.calculate_q(chi0, pd,
chi0_swGG, chi0_swxvG, chi0_swvv,
m1, m2, cut_G, A2_x)
energy_i.append(energy)
m1 = m2
a = 1 / chi0.kncomm.size
if ecut < ecutmax and a != 1.0:
# Chi0 will be summed again over chicomm, so we divide
# by its size:
chi0_swGG *= a
if chi0_swxvG is not None:
chi0_swxvG *= a
chi0_swvv *= a
self.energy_qi.append(energy_i)
self.write()
p()
e_i = np.dot(self.weight_q, np.array(self.energy_qi))
p('==========================================================')
p()
p('Total correlation energy:')
for e_cut, e in zip(self.ecut_i, e_i):
p('%6.0f: %6.4f eV' % (e_cut * Hartree, e * Hartree))
p()
self.energy_qi = [] # important if another calculation is performed
if len(e_i) > 1:
self.extrapolate(e_i)
p('Calculation completed at: ', ctime())
p()
self.timer.stop('RPA')
self.timer.write(self.fd)
self.fd.flush()
return e_i * Hartree
def calculate(self, ecut, nbands=None, spin=False):
"""Calculate RPA correlation energy for one or several cutoffs.
ecut: float or list of floats
Plane-wave cutoff(s).
nbands: int
Number of bands (defaults to number of plane-waves).
spin: bool
Separate spin in response funtion.
(Only needed for beyond RPA methods that inherit this function).
"""
p = functools.partial(print, file=self.fd)
if isinstance(ecut, (float, int)):
ecut = ecut * (1 + 0.5 * np.arange(6))**(-2 / 3)
self.ecut_i = np.asarray(np.sort(ecut)) / Hartree
ecutmax = max(self.ecut_i)
if nbands is None:
p('Response function bands : Equal to number of plane waves')
else:
p('Response function bands : %s' % nbands)
p('Plane wave cutoffs (eV) :', end='')
for e in self.ecut_i:
p(' {0:.3f}'.format(e * Hartree), end='')
p()
p()
if self.filename and os.path.isfile(self.filename):
self.read()
self.world.barrier()
chi0 = Chi0(self.calc, 1j * Hartree * self.omega_w, eta=0.0,
intraband=False, hilbert=False,
txt=self.fd, timer=self.timer, world=self.world,
no_optical_limit=self.wstc,
nblocks=self.nblocks)
self.blockcomm = chi0.blockcomm
wfs = self.calc.wfs
if self.wstc:
with self.timer('WSTC-init'):
p('Using Wigner-Seitz truncated Coulomb potential.')
self.wstc = WignerSeitzTruncatedCoulomb(
wfs.gd.cell_cv, wfs.kd.N_c, self.fd)
nq = len(self.energy_qi)
nw = len(self.omega_w)
nGmax = max(count_reciprocal_vectors(ecutmax, wfs.gd, q_c)
for q_c in self.ibzq_qc[nq:])
mynGmax = (nGmax + self.nblocks - 1) // self.nblocks
nx = (1 + spin) * nw * mynGmax * nGmax
A1_x = np.empty(nx, complex)
if self.nblocks > 1:
A2_x = np.empty(nx, complex)
else:
A2_x = None
self.timer.start('RPA')
for q_c in self.ibzq_qc[nq:]:
if np.allclose(q_c, 0.0) and self.skip_gamma:
self.energy_qi.append(len(self.ecut_i) * [0.0])
self.write()
p('Not calculating E_c(q) at Gamma')
p()
continue
thisqd = KPointDescriptor([q_c])
pd = PWDescriptor(ecutmax, wfs.gd, complex, thisqd)
nG = pd.ngmax
mynG = (nG + self.nblocks - 1) // self.nblocks
chi0.Ga = self.blockcomm.rank * mynG
chi0.Gb = min(chi0.Ga + mynG, nG)
shape = (1 + spin, nw, chi0.Gb - chi0.Ga, nG)
chi0_swGG = A1_x[:np.prod(shape)].reshape(shape)
chi0_swGG[:] = 0.0
if self.wstc or np.allclose(q_c, 0.0):
# Wings (x=0,1) and head (G=0) for optical limit and three
# directions (v=0,1,2):
chi0_swxvG = np.zeros((1 + spin, nw, 2, 3, nG), complex)
chi0_swvv = np.zeros((1 + spin, nw, 3, 3), complex)
else:
chi0_swxvG = None
chi0_swvv = None
Q_aGii = chi0.initialize_paw_corrections(pd)
# First not completely filled band:
m1 = chi0.nocc1
p('# %s - %s' % (len(self.energy_qi), ctime().split()[-2]))
p('q = [%1.3f %1.3f %1.3f]' % tuple(q_c))
energy_i = []
for ecut in self.ecut_i:
if ecut == ecutmax:
# Nothing to cut away:
cut_G = None
m2 = nbands or nG
else:
cut_G = np.arange(nG)[pd.G2_qG[0] <= 2 * ecut]
m2 = len(cut_G)
p('E_cut = %d eV / Bands = %d:' % (ecut * Hartree, m2))
self.fd.flush()
energy = self.calculate_q(chi0, pd,
chi0_swGG, chi0_swxvG, chi0_swvv,
Q_aGii, m1, m2, cut_G, A2_x)
energy_i.append(energy)
m1 = m2
a = 1 / chi0.kncomm.size
if ecut < ecutmax and a != 1.0:
# Chi0 will be summed again over chicomm, so we divide
# by its size:
chi0_swGG *= a
if chi0_swxvG is not None:
chi0_swxvG *= a
chi0_swvv *= a
self.energy_qi.append(energy_i)
self.write()
p()
e_i = np.dot(self.weight_q, np.array(self.energy_qi))
p('==========================================================')
p()
p('Total correlation energy:')
for e_cut, e in zip(self.ecut_i, e_i):
p('%6.0f: %6.4f eV' % (e_cut * Hartree, e * Hartree))
p()
self.energy_qi = [] # important if another calculation is performed
if len(e_i) > 1:
self.extrapolate(e_i)
p('Calculation completed at: ', ctime())
p()
self.timer.stop('RPA')
self.timer.write(self.fd)
self.fd.flush()
return e_i * Hartree
def calculate_screened_potential(self):
"""Calculates the screened potential for each q-point in the 1st BZ.
Since many q-points are related by symmetry, the actual calculation is
only done for q-points in the IBZ and the rest are obtained by symmetry
transformations. Results are returned as a generator to that it is not
necessary to store a huge matrix for each q-point in the memory."""
# The decorator $timer('W') doesn't work for generators, do we will
# have to manually start and stop the timer here:
self.timer.start('W')
print('Calculating screened Coulomb potential', file=self.fd)
if self.wstc:
print('Using Wigner-Seitz truncated Coloumb potential',
file=self.fd)
if self.ppa:
print('Using Godby-Needs plasmon-pole approximation:',
file=self.fd)
print(' Fitting energy: i*E0, E0 = %.3f Hartee' % self.E0,
file=self.fd)
# use small imaginary frequency to avoid dividing by zero:
frequencies = [1e-10j, 1j * self.E0 * Hartree]
parameters = {'eta': 0,
'hilbert': False,
'timeordered': False,
'frequencies': frequencies}
else:
print('Using full frequency integration:', file=self.fd)
print(' domega0: {0:g}'.format(self.domega0 * Hartree),
file=self.fd)
print(' omega2: {0:g}'.format(self.omega2 * Hartree),
file=self.fd)
parameters = {'eta': self.eta * Hartree,
'hilbert': True,
'timeordered': True,
'domega0': self.domega0 * Hartree,
'omega2': self.omega2 * Hartree}
chi0 = Chi0(self.calc,
nbands=self.nbands,
ecut=self.ecut * Hartree,
intraband=False,
real_space_derivatives=False,
txt=self.filename + '.w.txt',
timer=self.timer,
keep_occupied_states=True,
nblocks=self.blockcomm.size,
no_optical_limit=self.wstc,
**parameters)
if self.wstc:
wstc = WignerSeitzTruncatedCoulomb(
self.calc.wfs.gd.cell_cv,
self.calc.wfs.kd.N_c,
chi0.fd)
else:
wstc = None
self.omega_w = chi0.omega_w
self.omegamax = chi0.omegamax
htp = HilbertTransform(self.omega_w, self.eta, gw=True)
htm = HilbertTransform(self.omega_w, -self.eta, gw=True)
# Find maximum size of chi-0 matrices:
gd = self.calc.wfs.gd
nGmax = max(count_reciprocal_vectors(self.ecut, gd, q_c)
for q_c in self.qd.ibzk_kc)
nw = len(self.omega_w)
size = self.blockcomm.size
mynGmax = (nGmax + size - 1) // size
mynw = (nw + size - 1) // size
# Allocate memory in the beginning and use for all q:
A1_x = np.empty(nw * mynGmax * nGmax, complex)
A2_x = np.empty(max(mynw * nGmax, nw * mynGmax) * nGmax, complex)
# Need to pause the timer in between iterations
self.timer.stop('W')
for iq, q_c in enumerate(self.qd.ibzk_kc):
self.timer.start('W')
if self.savew:
wfilename = self.filename + '.w.q%d.pckl' % iq
fd = opencew(wfilename)
if self.savew and fd is None:
# Read screened potential from file
with open(wfilename) as fd:
pd, W = pickle.load(fd)
else:
# First time calculation
pd, W = self.calculate_w(chi0, q_c, htp, htm, wstc, A1_x, A2_x)
if self.savew:
pickle.dump((pd, W), fd, pickle.HIGHEST_PROTOCOL)
self.timer.stop('W')
# Loop over all k-points in the BZ and find those that are related
# to the current IBZ k-point by symmetry
Q1 = self.qd.ibz2bz_k[iq]
done = set()
for s, Q2 in enumerate(self.qd.bz2bz_ks[Q1]):
if Q2 >= 0 and Q2 not in done:
s = self.qd.sym_k[Q2]
self.s = s
self.U_cc = self.qd.symmetry.op_scc[s]
time_reversal = self.qd.time_reversal_k[Q2]
self.sign = 1 - 2 * time_reversal
Q_c = self.qd.bzk_kc[Q2]
d_c = self.sign * np.dot(self.U_cc, q_c) - Q_c
assert np.allclose(d_c.round(), d_c)
yield pd, W, Q_c
done.add(Q2)
