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