def set_log(self, log=None):
"""Set output log."""
if log is None:
self.timer = nulltimer
elif log == '-':
self.timer = StepTimer(name='elph')
else:
self.timer = StepTimer(name='elph', out=open(log, 'w'))
def get_M(self, modes, log=None, q=0):
"""Calculate el-ph coupling matrix for given modes(s).
XXX:
kwarg "q=0" is an ugly hack for k-points.
There shuold be loops over q!
Note that modes must be given as a dictionary with mode
frequencies in eV and corresponding mode vectors in units
of 1/sqrt(amu), where amu = 1.6605402e-27 Kg is an atomic mass unit.
In short frequencies and mode vectors must be given in ase units.
::
d d ~
< w | -- v | w' > = < w | -- v | w'>
dP dP
_
\ ~a d . ~a
+ ) < w | p > -- /_\H < p | w' >
/_ i dP ij j
a,ij
_
\ d ~a . ~a
+ ) < w | -- p > /_\H < p | w' >
/_ dP i ij j
a,ij
_
\ ~a . d ~a
+ ) < w | p > /_\H < -- p | w' >
/_ i ij dP j
a,ij
"""
if log is None:
timer = nulltimer
elif log == '-':
timer = StepTimer(name='EPCM')
else:
timer = StepTimer(name='EPCM', out=open(log, 'w'))
modes1 = modes.copy()
#convert to atomic units
amu = 1.6605402e-27 # atomic unit mass [Kg]
me = 9.1093897e-31 # electron mass [Kg]
modes = {}
for k in modes1.keys():
modes[k / Hartree] = modes1[k] / np.sqrt(amu / me)
dvt_Gx, ddH_aspx = self.get_gradient()
from gpaw import restart
atoms, calc = restart('eq.gpw', txt=None)
if calc.wfs.S_qMM is None:
calc.initialize(atoms)
calc.initialize_positions(atoms)
wfs = calc.wfs
nao = wfs.setups.nao
bfs = wfs.basis_functions
dtype = wfs.dtype
spin = 0 # XXX
M_lii = {}
timer.write_now('Starting gradient of pseudo part')
for f, mode in modes.items():
mo = []
M_ii = np.zeros((nao, nao), dtype)
for a in self.indices:
mo.append(mode[a])
mode = np.asarray(mo).flatten()
dvtdP_G = np.dot(dvt_Gx, mode)
bfs.calculate_potential_matrix(dvtdP_G, M_ii, q=q)
tri2full(M_ii, 'L')
M_lii[f] = M_ii
timer.write_now('Finished gradient of pseudo part')
P_aqMi = calc.wfs.P_aqMi
# Add the term
# _
# \ ~a d . ~a
# ) < w | p > -- /_\H < p | w' >
# /_ i dP ij j
# a,ij
Ma_lii = {}
for f, mode in modes.items():
Ma_lii[f] = np.zeros_like(M_lii.values()[0])
timer.write_now('Starting gradient of dH^a part')
for f, mode in modes.items():
mo = []
for a in self.indices:
mo.append(mode[a])
mode = np.asarray(mo).flatten()
for a, ddH_spx in ddH_aspx.items():
ddHdP_sp = np.dot(ddH_spx, mode)
ddHdP_ii = unpack2(ddHdP_sp[spin])
Ma_lii[f] += dots(P_aqMi[a][q], ddHdP_ii, P_aqMi[a][q].T)
timer.write_now('Finished gradient of dH^a part')
timer.write_now('Starting gradient of projectors part')
dP_aMix = self.get_dP_aMix(calc.spos_ac, wfs, q, timer)
timer.write_now('Finished gradient of projectors part')
dH_asp = pickle.load(open('v.eq.pckl', 'rb'))[1]
Mb_lii = {}
for f, mode in modes.items():
Mb_lii[f] = np.zeros_like(M_lii.values()[0])
for f, mode in modes.items():
for a, dP_Mix in dP_aMix.items():
dPdP_Mi = np.dot(dP_Mix, mode[a])
dH_ii = unpack2(dH_asp[a][spin])
dPdP_MM = dots(dPdP_Mi, dH_ii, P_aqMi[a][q].T)
Mb_lii[f] -= dPdP_MM + dPdP_MM.T
# XXX The minus sign here is quite subtle.
# It is related to how the derivative of projector
# functions in GPAW is calculated.
# More thorough explanations, anyone...?
# Units of M_lii are Hartree/(Bohr * sqrt(m_e))
for mode in M_lii.keys():
M_lii[mode] += Ma_lii[mode] + Mb_lii[mode]
# conversion to eV. The prefactor 1 / sqrt(hb^2 / 2 * hb * f)
# has units Bohr * sqrt(me)
M_lii_1 = M_lii.copy()
M_lii = {}
for f in M_lii_1.keys():
M_lii[f * Hartree] = M_lii_1[f] * Hartree / np.sqrt(2 * f)
return M_lii
