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dft_tools/python/lattice_gf.py
2014-11-18 11:44:14 +01:00

68 lines
3.5 KiB
Python

def lattice_gf(self, ik, mu, iw_or_w="iw", beta=40, broadening, mesh=None, with_Sigma=True, with_dc=True):
"""Calculates the lattice Green function from the DFT hopping and the self energy at k-point number ik
and chemical potential mu."""
ntoi = self.spin_names_to_ind[self.SO]
spn = self.spin_block_names[self.SO]
if (iw_or_w != "iw") and (iw_or_w != "w"):
raise ValueError, "lattice_gf: implemented only for Re/Im frequency functions."
# Are we including Sigma?
if with_Sigma:
if with_dc: sigma_inc_dc = self.add_dc()
Sigma_imp = getattr(self,"Sigma_imp_"+iw_or_w)
if iw_or_w == "iw": beta = Sigma_imp[0].mesh.beta # override beta if Sigma_iw is present
else:
if (iw_or_w == "w") and (mesh is None):
raise ValueError, "Give the mesh=(om_min,om_max,n_points) for the lattice GfReFreq."
# Check if G_upfold is present
set_up_G_upfold = False # Assume not
if not hasattr(self,"G_upfold_"+iw_or_w)):
set_up_G_upfold = True # Need to create G_upfold_iw
setattr(self,"G_upfold_"+iw_or_w,0) # Set temporarily to zero
else: # Check that existing GF is consistent
GFsize = [ gf.N1 for bname,gf in getattr(self,"G_upfold_"+iw_or_w)]
unchangedsize = all( [ self.n_orbitals[ik,ntoi[spn[isp]]]==GFsize[isp]
for isp in range(self.n_spin_blocks[self.SO]) ] )
if not unchangedsize: set_up_G_upfold = True
if (iw_or_w != "iw") and (self.G_upfold_iw.mesh.beta != beta): # additional check for ImFreq
set_up_G_upfold = True
G_upfold = getattr(self,"G_upfold_"+iw_or_w)
# Set up G_upfold
if set_up_G_upfold:
block_structure = [ range(self.n_orbitals[ik,ntoi[sp]]) for sp in spn ]
gf_struct = [ (spn[isp], block_structure[isp]) for isp in range(self.n_spin_blocks[self.SO]) ]
block_ind_list = [block for block,inner in gf_struct]
if with_Sigma:
glist = lambda : [ GfImFreq(indices=inner,mesh=Sigma_imp[0].mesh) for block,inner in gf_struct]
else:
if iw_or_w == "iw":
glist = lambda : [ GfImFreq(indices=inner,beta=beta) for block,inner in gf_struct]
elif iw_or_w == "w":
glist = lambda : [ GfImFreq(indices=inner,window=(mesh[0],mesh[1]),n_points=mesh[2]) for block,inner in gf_struct]
G_upfold = BlockGf(name_list = block_ind_list, block_list = glist(), make_copies = False)
G_upfold.zero()
if iw_or_w == "iw":
G_upfold << iOmega_n
elif iw_or_w == "w":
G_upfold << Omega + 1j*broadening
idmat = [numpy.identity(self.n_orbitals[ik,ntoi[sp]],numpy.complex_) for sp in spn]
M = copy.deepcopy(idmat)
for ibl in range(self.n_spin_blocks[self.SO]):
ind = ntoi[spn[ibl]]
n_orb = self.n_orbitals[ik,ind]
M[ibl] = self.hopping[ik,ind,0:n_orb,0:n_orb] - (idmat[ibl]*mu) - (idmat[ibl] * self.h_field * (1-2*ibl))
G_upfold -= M
if with_Sigma:
for icrsh in range(self.n_corr_shells):
for bname,gf in G_upfold: gf -= self.upfold(ik,icrsh,bname,sigma_inc_dc[icrsh][bname],gf)
G_upfold.invert()
return G_upfold