qpms/qpms/tmatrices.py

472 lines
17 KiB
Python
Raw Permalink Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

"""
Mostly legacy code, but still kept for reference.
Might be removed in future versions.
"""
import numpy as np
use_moble_quaternion = False
try:
import quaternion, spherical_functions as sf # because of the Wigner matrices. These imports are SLOW.
use_moble_quaternion = True
except ImportError:
use_moble_quaternion = False
import re
from .constants import hbar, eV, pi, c
from .cycommon import get_mn_y, get_nelem
from .cyquaternions import CQuat
ň = np.newaxis
from .types import NormalizationT, TMatrixSpec
# Transformations of spherical bases
def WignerD_mm(l, quat):
"""
Calculates Wigner D matrix (as an numpy (2*l+1,2*l+1)-shaped array)
for order l, and a rotation given by quaternion quat.
This represents the rotation of spherical vector basis
TODO doc
"""
if use_moble_quaternion:
indices = np.array([ [l,i,j] for i in range(-l,l+1) for j in range(-l,l+1)])
Delems = sf.Wigner_D_element(quat, indices).reshape(2*l+1,2*l+1)
return Delems
else:
Delems = np.zeros((2*l+1, 2*l+1), dtype=complex)
for i in range(-l,l+1):
for j in range(-l,l+1):
Delems[i,j] = quat.wignerDelem(l, i, j)
return Delems
def WignerD_mm_fromvector(l, vect):
"""
TODO doc
"""
if use_moble_quaternion:
return WignerD_mm(l, quaternion.from_rotation_vector(vect))
else:
return WignerD_mm(l, CQuat.from_rotvector(vect))
def WignerD_yy(lmax, quat):
"""
TODO doc
"""
my, ny = get_mn_y(lmax)
Delems = np.zeros((len(my),len(my)),dtype=complex)
b_in = 0
e_in = None
for l in range(1,lmax+1):
e_in = b_in + 2*l+1
Delems[b_in:e_in,b_in:e_in] = WignerD_mm(l, quat)
b_in = e_in
return Delems
def WignerD_yy_fromvector(lmax, vect):
"""
TODO doc
"""
if use_moble_quaternion:
return WignerD_yy(lmax, quaternion.from_rotation_vector(vect))
else:
return WignerD_yy(lMax, CQuat.from_rotvector(vect))
def identity_yy(lmax):
"""
TODO doc
"""
return np.eye(lMax2nelem(lMax))
def identity_tyty(lmax):
"""
TODO doc
"""
nelem = lMax2nelem(lmax)
return np.eye(2*nelem).reshape((2,nelem,2,nelem))
def xflip_yy(lmax):
"""
TODO doc
xflip = δ(m + m') δ(l - l')
(i.e. ones on the (m' m) antidiagonal
"""
my, ny = get_mn_y(lmax)
elems = np.zeros((len(my),len(my)),dtype=int)
b_in = 0
e_in = None
for l in range(1,lmax+1):
e_in = b_in + 2*l+1
elems[b_in:e_in,b_in:e_in] = np.eye(2*l+1)[::-1,:]
b_in = e_in
return elems
def xflip_tyy(lmax):
fl_yy = xflip_yy(lmax)
return np.array([fl_yy,-fl_yy])
def xflip_tyty(lmax):
fl_yy = xflip_yy(lmax)
nelem = fl_yy.shape[0]
fl_tyty = np.zeros((2,nelem,2,nelem),dtype=int)
fl_tyty[0,:,0,:] = fl_yy
fl_tyty[1,:,1,:] = -fl_yy
return fl_tyty
def yflip_yy(lmax):
"""
TODO doc
yflip = rot(z,pi/2) * xflip * rot(z,-pi/2)
= δ(m + m') δ(l - l') * (-1)**m
"""
my, ny = get_mn_y(lmax)
elems = xflip_yy(lmax)
elems[(my % 2)==1] = elems[(my % 2)==1] * -1 # Obvious sign of tiredness (this is correct but ugly; FIXME)
return elems
def yflip_tyy(lmax):
fl_yy = yflip_yy(lmax)
return np.array([fl_yy,-fl_yy])
def yflip_tyty(lmax):
fl_yy = yflip_yy(lmax)
nelem = fl_yy.shape[0]
fl_tyty = np.zeros((2,nelem,2,nelem),dtype=int)
fl_tyty[0,:,0,:] = fl_yy
fl_tyty[1,:,1,:] = -fl_yy
return fl_tyty
def zflip_yy(lmax):
"""
TODO doc
zflip = (-1)^(l+m)
"""
my, ny = get_mn_y(lmax)
elems = np.zeros((len(my), len(my)), dtype=int)
b_in = 0
e_in = None
for l in range(1,lmax+1):
e_in = b_in + 2*l+1
elems[b_in:e_in,b_in:e_in] = np.diag([(-1)**i for i in range(e_in-b_in)])
b_in = e_in
return elems
def zflip_tyy(lmax):
fl_yy = zflip_yy(lmax)
return np.array([fl_yy,-fl_yy])
def zflip_tyty(lmax):
fl_yy = zflip_yy(lmax)
nelem = fl_yy.shape[0]
fl_tyty = np.zeros((2,nelem,2,nelem),dtype=int)
fl_tyty[0,:,0,:] = fl_yy
fl_tyty[1,:,1,:] = -fl_yy
return fl_tyty
def zrotN_yy(N, lMax):
return WignerD_yy_fromvector(lMax, np.array([0,0,pi * (2/N)]))
def op_yy2tyty(yyop):
'''
Broadcasts an yy operator to tyty operator without considering mirroring effects.
Good (maybe only) for rotations.
'''
return np.moveaxis(np.eye(2)[:,:,ň,ň] * yyop, 2,1)
def zrotN_tyty(N, lMax):
return op_yy2tyty(zrotN_yy(N, lMax))
def parity_yy(lmax):
"""
Parity operator (flip in x,y,z)
parity = (-1)**l
"""
my, ny = get_mn_y(lmax)
return np.diag((-1)**ny)
# BTW parity (xyz-flip) is simply (-1)**ny
#----------------------------------------------------#
# Loading T-matrices from scuff-tmatrix output files #
#----------------------------------------------------#
# We don't really need this particular function anymore, but...
def _scuffTMatrixConvert_EM_01(EM):
#print(EM)
if (EM == b'E'):
return 1
elif (EM == b'M'):
return 0
else:
return None
def loadScuffTMatrices(fileName, normalisation = 1, version = 'old', freqscale = None, order = None):
"""
TODO doc
version describes version of scuff-em. It is either 'old' or 'new'.
default order is ('N','M') with 'old' version, ('M','N') with 'new'
"""
oldversion = (version == 'old')
μm = 1e-6
table = np.genfromtxt(fileName,
converters={1: _scuffTMatrixConvert_EM_01, 4: _scuffTMatrixConvert_EM_01} if oldversion else None,
skip_header = 0 if oldversion else 5,
usecols = None if oldversion else (0, 2, 3, 4, 6, 7, 8, 9, 10),
dtype=[('freq', '<f8'),
('outc_type', '<i8'), ('outc_l', '<i8'), ('outc_m', '<i8'),
('inc_type', '<i8'), ('inc_l', '<i8'), ('inc_m', '<i8'),
('Treal', '<f8'), ('Timag', '<f8')]
if oldversion else
[('freq', '<f8'),
('outc_l', '<i8'), ('outc_m', '<i8'), ('outc_type', '<i8'),
('inc_l', '<i8'), ('inc_m', '<i8'), ('inc_type', '<i8'),
('Treal', '<f8'), ('Timag', '<f8')]
)
lMax=np.max(table['outc_l'])
my,ny = get_mn_y(lMax)
nelem = len(ny)
TMatrix_sz = nelem**2 * 4 # number of rows for each frequency: nelem * nelem spherical incides, 2 * 2 E/M types
freqs_weirdunits = table['freq'][::TMatrix_sz].copy()
freqs = freqs_weirdunits * c / μm
# The iteration in the TMatrix file goes in this order (the last one iterates fastest, i.e. in the innermost loop):
# freq outc_l outc_m outc_type inc_l inc_m inc_type
# The l,m mapping is the same as is given by my get_mn_y function, so no need to touch that
TMatrices_tmp_real = table['Treal'].reshape(len(freqs), nelem, 2, nelem, 2)
TMatrices_tmp_imag = table['Timag'].reshape(len(freqs), nelem, 2, nelem, 2)
# There are two přoblems with the previous matrices. First, we want to have the
# type indices first, so we want a shape (len(freqs), 2, nelem, 2, nelem) as in the older code.
# Second, M-waves come first, so they have now 0-valued index, and E-waves have 1-valued index,
# which we want to be inverted.
TMatrices = np.zeros((len(freqs),2,nelem,2,nelem),dtype=complex)
reorder = (0,1)
if ((order == ('N', 'M')) and not oldversion): # reverse order for the new version
reorder = (1,0)
# TODO reverse order for the old version...
for inc_type in (0,1):
for outc_type in (0,1):
TMatrices[:,reorder[outc_type],:,reorder[inc_type],:] = TMatrices_tmp_real[:,:,outc_type,:,inc_type]+1j*TMatrices_tmp_imag[:,:,outc_type,:,inc_type]
# IMPORTANT: now we are going from Reid's/Kristensson's/Jackson's/whoseever convention to Taylor's convention
# TODO make these consistent with what is defined in qpms_types.h (implement all possibilities)
if normalisation == 1:
TMatrices[:,:,:,:,:] = TMatrices[:,:,:,:,:] * np.sqrt(ny*(ny+1))[ň,ň,ň,ň,:] / np.sqrt(ny*(ny+1))[ň,ň,:,ň,ň]
elif normalisation == 2: # Kristensson?
pass
if freqscale is not None:
freqs *= freqscale
freqs_weirdunits *= freqscale
return (TMatrices, freqs, freqs_weirdunits, lMax)
# misc tensor maniputalion
def apply_matrix_left(matrix, tensor, axis):
"""
TODO doc
Apply square matrix to a given axis of a tensor, so that the result retains the shape
of the original tensor. The summation goes over the second index of the matrix and the
given tensor axis.
"""
tmp = np.tensordot(matrix, tensor, axes=(-1,axis))
return np.moveaxis(tmp, 0, axis)
def apply_ndmatrix_left(matrix,tensor,axes):
"""
Generalized apply_matrix_left, the matrix can have more (2N) abstract dimensions,
like M[i,j,k,...z,i,j,k,...,z]. N axes have to be specified in a tuple, corresponding
to the axes 0,1,...N-1 of the matrix
"""
N = len(axes)
matrix = np.tensordot(matrix, tensor, axes=([-N+axn for axn in range(N)],axes))
matrix = np.moveaxis(matrix, range(N), axes)
return matrix
def apply_ndmatrix_right(tensor, matrix, axes):
"""
Right-side analogue of apply_ndmatrix_lift.
Multiplies a tensor with a 2N-dimensional matrix, conserving the axis order.
"""
N = len(axes)
matrix = np.tensordot(tensor, matrix, axes = (axes, range(N)))
matrix = np.moveaxis(matrix, [-N+axn for axn in range(N)], axes)
return matrix
def ndmatrix_Hconj(matrix):
"""
For 2N-dimensional matrix, swap the first N and last N matrix, and complex conjugate.
"""
twoN = len(matrix.shape)
if not twoN % 2 == 0:
raise ValueError("The matrix has to have even number of axes.")
N = twoN//2
matrix = np.moveaxis(matrix, range(N), range(N, 2*N))
return matrix.conj()
def symz_indexarrays(lMax, npart = 1):
"""
Returns indices that are used for separating the in-plane E ('TE' in the photonic crystal
jargon) and perpendicular E ('TM' in the photonic crystal jargon) modes
in the z-mirror symmetric systems.
Parameters
----------
lMax : int
The maximum degree cutoff for the T-matrix to which these indices will be applied.
npart : int
Number of particles (TODO better description)
Returns
-------
TEč, TMč : (npart * 2 * nelem)-shaped bool ndarray
Mask arrays corresponding to the 'TE' and 'TM' modes, respectively.
"""
my, ny = get_mn_y(lMax)
nelem = len(my)
ž = np.arange(2*nelem) # single particle spherical wave indices
= ž // nelem # tž == 0: electric waves, tž == 1: magnetic waves
= my[ž%nelem]
= ny[ž%nelem]
TEž = ž[(++) % 2 == 0]
TMž = ž[(++) % 2 == 1]
č = np.arange(npart*2*nelem) # spherical wave indices for multiple particles (e.g. in a unit cell)
žč = č % (2* nelem)
= [žč]
= [žč]
= [žč]
TEč = č[(++) % 2 == 0]
TMč = č[(++) % 2 == 1]
return (TEč, TMč)
"""
Processing T-matrix related operations from scripts
===================================================
see also scripts_common.py
The unit cell is defined by a dict particle_specs and a list TMatrix_specs.
This particular module has to provide the T-matrices according to what is defined
in TMatrix_specs
TMatrix_specs is a list of tuples (lMax_override, TMatrix_path, ops)
where
- TMatrix_path is path to the file generated by scuff-tmatrix
- lMax_override is int or None; if it is int and less than the lMax found from the T-matrix file,
lMax_override is used as the order cutoff for the output T-matrix.
- ops is an iterable of tuples (optype, opargs) where currently optype can be 'sym' or 'tr'
for symmetrization operation or some other transformation.
"""
#TODO FEATURE more basic group symmetry operations, cf. http://symmetry.otterbein.edu/tutorial/index.html
# This is for finite „fractional“ rotations along the z-axis (mCN means rotation of 2π*(m/N))
reCN = re.compile('(\d*)C(\d+)') # TODO STYLE make this regexp also accept the 3*C_5-type input, eqiv. to 3C5
def get_TMatrix_fromspec(tmatrix_spec):
''' TODO doc
returns (TMatrices, freqs, lMax)
'''
lMax_override, tmpath, ops = tmatrix_spec
TMatrices, freqs, freqs_weirdunits, lMax = loadScuffTMatrices(tmpath)
if lMax_override is not None and (lMax_override < lMax_orig):
nelem = get_nelem(lMax_override)
TMatrices = TMatrices[...,0:nelem,:,0:nelem]
lMax = lMax_override
for (optype, opargs) in ops:
if optype == 'sym':
mCN = reCN.match(opargs)
if opargs == 'C2' or opargs == 'C_2':
opmat = apply_matrix_left(yflip_yy(lMax), xflip_yy(lMax), -1)
TMatrices = (TMatrices + apply_matrix_left(opmat, apply_matrix_left(opmat, TMatrices, -3), -1))/2
elif opargs == 'σ_x' or opargs == 'σx':
opmat = xflip_tyty(lMax)
TMatrices = (TMatrices + apply_ndmatrix_left(opmat, apply_ndmatrix_left(opmat, TMatrices, (-4,-3)),(-2,-1)))/2
elif opargs == 'σ_y' or opargs == 'σy':
opmat = yflip_tyty(lMax)
TMatrices = (TMatrices + apply_ndmatrix_left(opmat, apply_ndmatrix_left(opmat, TMatrices, (-4,-3)),(-2,-1)))/2
elif opargs == 'σ_z' or opargs == 'σz':
opmat = zflip_tyty(lMax)
TMatrices = (TMatrices + apply_ndmatrix_left(opmat, apply_ndmatrix_left(opmat, TMatrices, (-4,-3)),(-2,-1)))/2
elif mCN:
rotN = int(mCN.group(2)) # the possible m is ignored
TMatrix_contribs = np.empty((rotN,)+TMatrices.shape, dtype=np.complex_)
for i in range(rotN):
rotangle = 2*np.pi*i / rotN
rot = WignerD_yy_fromvector(lMax, np.array([0,0,rotangle]))
rotinv = WignerD_yy_fromvector(lMax, np.array([0,0,-rotangle]))
TMatrix_contribs[i] = apply_matrix_left(rot, apply_matrix_left(rotinv, TMatrices, -3), -1)
TMatrices = np.sum(TMatrix_contribs, axis=0) / rotN
elif opargs == 'C_inf' or opargs == 'Cinf' or opargs == 'C_∞' or opargs == 'C∞':
raise ValueError('not implemented: ', opargs) # TODO FEATURE
else:
raise ValueError('not implemented: ', opargs)
elif optype == 'tr':
mCN = reCN.match(opargs)
if opargs == 'C2' or opargs == 'C_2':
opmat = apply_matrix_left(yflip_yy(lMax), xflip_yy(lMax), -1)
TMatrices = apply_matrix_left(opmat, apply_matrix_left(opmat, TMatrices, -3), -1)/2
elif opargs == 'σ_x' or opargs == 'σx':
opmat = xflip_tyty(lMax)
TMatrices = apply_ndmatrix_left(opmat, apply_ndmatrix_left(opmat, TMatrices, (-4,-3)),(-2,-1))/2
elif opargs == 'σ_y' or opargs == 'σy':
opmat = yflip_tyty(lMax)
TMatrices = apply_ndmatrix_left(opmat, apply_ndmatrix_left(opmat, TMatrices, (-4,-3)),(-2,-1))/2
elif opargs == 'σ_z' or opargs == 'σz':
opmat = zflip_tyty(lMax)
TMatrices = apply_ndmatrix_left(opmat, apply_ndmatrix_left(opmat, TMatrices, (-4,-3)),(-2,-1))/2
elif mCN:
rotN = int(mCN.group(2))
power = int(mCN.group(1)) if mCN.group(1) else 1
rotangle = 2*np.pi*power / rotN
rot = WignerD_yy_fromvector(lMax, np.array([0,0,rotangle]))
rotinv = WignerD_yy_fromvector(lMax, np.array([0,0,-rotangle]))
TMatrices = apply_matrix_left(rot, apply_matrix_left(rotinv, TMatrices, -3), -1)
else:
raise ValueError('not implemented: ', opargs)
else:
raise ValueError('not implemented: ', optype)
return (TMatrices, freqs, lMax)
class TMatrix(TMatrixSpec):
'''
TODO doc
TODO support for different/multiple interpolators
'''
def __init__(self, tmatrix_spec):
from scipy import interpolate
#self.specification = tmatrix_spec
self.lMax_override = tmatrix_spec.lMax_override
self.tmatrix_path = tmatrix_spec.tmatrix_path
self.ops = tmatrix_spec.ops
self.tmdata, self.freqs, self.lMax = get_TMatrix_fromspec(tmatrix_spec)
self.nelem = get_nelem(self.lMax)
#self._interpolators = dict()
self.default_interpolator = interpolate.interp1d(self.freqs,
self.tmdata, axis=0, kind='linear', fill_value='extrapolate')
self.normalization = NormalizationT.TAYLOR # TODO others are not supported by the loading functions
def atfreq(self, freq):
freqarray = np.array(freq, copy=False)
if freqarray.shape: # not just a scalar
tm_interp = np.empty(freqarray.shape + (2, self.nelem, 2, self.nelem), dtype=np.complex_)
for i in np.ndindex(freqarray.shape):
tm_interp[i] = self.default_interpolator(freqarray[i])
return tm_interp
else: # scalar
return self.default_interpolator(freq)
__getitem__ = atfreq # might be changed later, use atfreq to be sure
def perform_tmspecs(tmspecs):
"""Takes a sequence of TMatrixSpec or TMatrix instances and returns
a list of corresponding TMatrix instances"""
return [(tmspec if hasattr(tmspec, "tmdata") else TMatrix(tmspec))
for tmspec in tmspecs]