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Add more integrators for the transport integral

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It is now possible to use trapz, simps and quadl (with cubic
        spline) to perform the omega integration needed in the transport code.
This commit is contained in:
Manuel Zingl 2015-07-28 17:21:13 +02:00
parent 6ecbf6720d
commit b6e33ecc23
1 changed files with 49 additions and 27 deletions
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60
python/sumk_dft_tools.py
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@ -18,13 +18,15 @@
# TRIQS. If not, see <http://www.gnu.org/licenses/>.
#
################################################################################
import sys
from types import *
import numpy
from pytriqs.gf.local import *
import pytriqs.utility.mpi as mpi
from symmetry import *
from sumk_dft import SumkDFT
from scipy.integrate import *
from scipy.interpolate import *
class SumkDFTTools(SumkDFT):
"""
@ -613,8 +615,8 @@ class SumkDFTTools(SumkDFT):
if (energy_window[0] >= energy_window[1] or energy_window[0] >= 0 or energy_window[1] <= 0):
assert 0, "transport_distribution: energy_window wrong!"
if (abs(self.fermi_dis(energy_window[0]*beta)*self.fermi_dis(-energy_window[0]*beta)) > 1e-5
or abs(self.fermi_dis(energy_window[1]*beta)*self.fermi_dis(-energy_window[1]*beta)) > 1e-5):
if (abs(self.fermi_dis(energy_window[0],beta)*self.fermi_dis(-energy_window[0],beta)) > 1e-5
or abs(self.fermi_dis(energy_window[1],beta)*self.fermi_dis(-energy_window[1],beta)) > 1e-5):
mpi.report("\n####################################################################")
mpi.report("transport_distribution: WARNING - energy window might be too narrow!")
mpi.report("####################################################################\n")
@ -719,7 +721,7 @@ class SumkDFTTools(SumkDFT):
/ self.cellvolume(self.lattice_type, self.lattice_constants, self.lattice_angles)[1] / self.n_symmetries)
def transport_coefficient(self, direction, iq, n, beta):
def transport_coefficient(self, direction, iq, n, beta, method=None):
r"""
Calculates the transport coefficient A_n in a given direction for a given :math:`\Omega`. The required members (Gamma_w, directions, Om_mesh) have to be obtained first
by calling the function :meth:`transport_distribution <pytriqs.applications.dft.sumk_dft_tools.SumkDFTTools.transport_distribution>`. For n>0 A is set to NaN if :math:`\Omega` is not 0.0.
@ -734,6 +736,9 @@ class SumkDFTTools(SumkDFT):
Number of the desired moment of the transport distribution.
beta : double
Inverse temperature :math:`\beta`.
method : string
Integration method: cubic spline and scipy.integrate.quad ('quad'), simpson rule ('simps'), trapezoidal rule ('trapz'), rectangular integration (otherwise)
Note that the sampling points of the the self-energy are used!
Returns
-------
@ -744,24 +749,39 @@ class SumkDFTTools(SumkDFT):
if not (mpi.is_master_node()): return
assert hasattr(self,'Gamma_w'), "transport_coefficient: Run transport_distribution first or load data from h5!"
if (self.Om_mesh[iq] == 0.0 or n == 0.0):
A = 0.0
omegaT = self.omega * beta
d_omega = self.omega[1] - self.omega[0]
# setup the integrand
if (self.Om_mesh[iq] == 0.0):
for iw in xrange(self.Gamma_w[direction].shape[1]):
A += self.Gamma_w[direction][iq, iw] * self.fermi_dis(omegaT[iw]) * self.fermi_dis(-omegaT[iw]) * numpy.float(omegaT[iw])**n * d_omega
A_int = self.Gamma_w[direction][iq] * (self.fermi_dis(self.omega,beta) * self.fermi_dis(-self.omega,beta)) * (self.omega*beta)**n
elif (n == 0.0):
A_int = self.Gamma_w[direction][iq] * (self.fermi_dis(self.omega,beta) - self.fermi_dis(self.omega+self.Om_mesh[iq],beta))/(self.Om_mesh[iq]*beta)
# w-integration
if method == 'quad':
# quad on interpolated w-points with cubic spline
A_int_interp = interp1d(self.omega,A_int,kind='cubic')
A = quad(A_int_interp, min(self.omega), max(self.omega), epsabs=1.0e-12,epsrel=1.0e-12,limit = 500)
A = A[0]
elif method == 'simps':
# simpson rule for w-grid
A = simps(A_int,self.omega)
elif method == 'trapz':
# trapezoidal rule for w-grid
A = numpy.trapz(A_int,self.omega)
else:
# rectangular integration for w-grid (orignal implementation)
d_w = self.omega[1] - self.omega[0]
for iw in xrange(self.Gamma_w[direction].shape[1]):
A += (self.Gamma_w[direction][iq, iw] * (self.fermi_dis(omegaT[iw]) - self.fermi_dis(omegaT[iw] + self.Om_mesh[iq] * beta))
/ (self.Om_mesh[iq] * beta) * d_omega)
A += A_int[iw]*d_w
A = A * numpy.pi * (2.0-self.SP)
else:
A = numpy.nan
A = A * numpy.pi * (2.0-self.SP)
return A
def conductivity_and_seebeck(self, beta):
def conductivity_and_seebeck(self, beta, method=None):
r"""
Calculates the Seebeck coefficient and the optical conductivity by calling
:meth:`transport_coefficient <pytriqs.applications.dft.sumk_dft_tools.SumkDFTTools.transport_coefficient>`.
@ -794,8 +814,8 @@ class SumkDFTTools(SumkDFT):
for direction in self.directions:
for iq in xrange(n_q):
A0[direction][iq] = self.transport_coefficient(direction, iq=iq, n=0, beta=beta)
A1[direction][iq] = self.transport_coefficient(direction, iq=iq, n=1, beta=beta)
A0[direction][iq] = self.transport_coefficient(direction, iq=iq, n=0, beta=beta, method=method)
A1[direction][iq] = self.transport_coefficient(direction, iq=iq, n=1, beta=beta, method=method)
print "A_0 in direction %s for Omega = %.2f %e a.u." % (direction, self.Om_mesh[iq], A0[direction][iq])
print "A_1 in direction %s for Omega = %.2f %e a.u." % (direction, self.Om_mesh[iq], A1[direction][iq])
if ~numpy.isnan(A1[direction][iq]):
@ -810,7 +830,7 @@ class SumkDFTTools(SumkDFT):
return self.optic_cond, self.seebeck
def fermi_dis(self, x):
def fermi_dis(self,w,beta):
r"""
Fermi distribution.
@ -819,11 +839,13 @@ class SumkDFTTools(SumkDFT):
Parameters
----------
x : double
Inverse temperature times frequency :math:`\beta\omega`.
w : double
frequency
beta : double
inverse temperature
Returns
-------
f : double
"""
return 1.0/(numpy.exp(x)+1)
return 1.0/(numpy.exp(w*beta)+1)