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spar ... master

Author SHA1 Message Date
36431cd0e4 enable numpy 2.0 and recent scipy 2024-07-29 02:25:16 -07:00
739e96df3d avoid a copy 2024-07-29 00:34:17 -07:00
63e7cb949f explicitly specify closed variables 2024-07-29 00:33:58 -07:00
c53a3c4d84 unused var 2024-07-29 00:33:43 -07:00
5dd9994e76 improve some type annotations 2024-07-29 00:32:52 -07:00
1021768e30 simplify indentation 2024-07-29 00:32:20 -07:00
95e923d7b7 improve error handling 2024-07-29 00:32:03 -07:00
3f8802cb5f use strict zip 2024-07-29 00:31:44 -07:00
43bb0ba379 use generators where applicable 2024-07-29 00:31:16 -07:00
e19968bb9f linter-related test updates 2024-07-29 00:30:00 -07:00
43f038d761 modernize type annotations 2024-07-29 00:29:39 -07:00
d5fca741d1 remove type:ignore from scipy imports (done at pyproject.toml level) 2024-07-29 00:27:59 -07:00
ca94ad1b25 use path.open() 2024-07-29 00:23:08 -07:00
10f26c12b4 add ruff and mypy configs 2024-07-29 00:22:54 -07:00
ee51c7db49 improve type annotations 2024-07-28 23:23:47 -07:00
36bea6a593 drop unused import 2024-07-28 23:23:21 -07:00
b16b35d84a use new numpy.random.Generator approach 2024-07-28 23:23:11 -07:00
6f3ae5a64f explicitly re-export some names 2024-07-28 23:22:21 -07:00
99c22d572f bump numpy version 2024-07-28 23:21:59 -07:00
2f00baf0c6 fixup cylindrical wg example 2024-07-18 19:31:17 -07:00
2712d96f2a add notes on references 2024-07-18 19:31:17 -07:00
dc3e733e7f flake8 fixes 2024-07-18 19:31:17 -07:00
95e3f71b40 use f-strings in place of .format() 2024-07-18 19:31:17 -07:00
639f88bba8 add sensitivity calculation 2024-07-18 19:31:17 -07:00
ccfd4fbf04 use parentheses instead of backslash 2024-07-15 16:32:48 -07:00
77715da8b4 Use raw strings to avoid double backslashes 2024-07-15 16:32:31 -07:00
2d48858973 drop duplicate import 2024-07-15 16:10:51 -07:00
8c49710861 black bg for tex svgs 2024-07-14 22:09:16 -07:00
22565328ab use parens in place of backslashes 2024-07-14 22:08:52 -07:00
4c8a07bf20 Use raw strings to eliminate repeated backslashes 2024-07-14 22:08:30 -07:00
b47dec0317 bump version to v0.9 2024-03-30 18:08:51 -07:00
52d297bb31 add links to pypi and github 2024-03-30 18:07:50 -07:00
7b4b2058bb bump minmum python to 3.11 2024-03-30 18:07:30 -07:00
950a5831ec should also use dxbg 2024-03-18 10:34:21 -07:00
91d89550a1 comment 2024-03-18 10:34:09 -07:00
35 changed files with 851 additions and 1743 deletions

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@ -157,7 +157,8 @@ def main():
e[1][tuple(grid.shape//2)] += field_source(t)
update_H(e, h)
print('iteration {}: average {} iterations per sec'.format(t, (t+1)/(time.perf_counter()-start)))
avg_rate = (t + 1)/(time.perf_counter() - start))
print(f'iteration {t}: average {avg_rate} iterations per sec')
sys.stdout.flush()
if t % 20 == 0:

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@ -3,7 +3,7 @@ import numpy
from numpy.linalg import norm
from meanas.fdmath import vec, unvec
from meanas.fdfd import waveguide_mode, functional, scpml
from meanas.fdfd import waveguide_cyl, functional, scpml
from meanas.fdfd.solvers import generic as generic_solver
import gridlock
@ -37,29 +37,34 @@ def test1(solver=generic_solver):
xyz_max = numpy.array([800, y_max, z_max]) + (pml_thickness + 2) * dx
# Coordinates of the edges of the cells.
half_edge_coords = [numpy.arange(dx/2, m + dx/2, step=dx) for m in xyz_max]
half_edge_coords = [numpy.arange(dx / 2, m + dx / 2, step=dx) for m in xyz_max]
edge_coords = [numpy.hstack((-h[::-1], h)) for h in half_edge_coords]
edge_coords[0] = numpy.array([-dx, dx])
# #### Create the grid and draw the device ####
grid = gridlock.Grid(edge_coords)
epsilon = grid.allocate(n_air**2, dtype=numpy.float32)
grid.draw_cuboid(epsilon, center=center, dimensions=[8e3, w, th], eps=n_wg**2)
grid.draw_cuboid(epsilon, center=center, dimensions=[8e3, w, th], foreground=n_wg**2)
dxes = [grid.dxyz, grid.autoshifted_dxyz()]
for a in (1, 2):
for p in (-1, 1):
dxes = scmpl.stretch_with_scpml(dxes, omega=omega, axis=a, polarity=p,
thickness=pml_thickness)
dxes = scpml.stretch_with_scpml(
dxes,
omega=omega,
axis=a,
polarity=p,
thickness=pml_thickness,
)
wg_args = {
'omega': omega,
'dxes': [(d[1], d[2]) for d in dxes],
'epsilon': vec(g.transpose([1, 2, 0]) for g in epsilon),
'epsilon': vec(epsilon.transpose([0, 2, 3, 1])),
'r0': r0,
}
wg_results = waveguide_mode.solve_waveguide_mode_cylindrical(mode_number=0, **wg_args)
wg_results = waveguide_cyl.solve_mode(mode_number=0, **wg_args)
E = wg_results['E']
@ -70,20 +75,17 @@ def test1(solver=generic_solver):
'''
Plot results
'''
def pcolor(v):
def pcolor(fig, ax, v, title):
vmax = numpy.max(numpy.abs(v))
pyplot.pcolor(v.T, cmap='seismic', vmin=-vmax, vmax=vmax)
pyplot.axis('equal')
pyplot.colorbar()
mappable = ax.pcolormesh(v.T, cmap='seismic', vmin=-vmax, vmax=vmax)
ax.set_aspect('equal', adjustable='box')
ax.set_title(title)
ax.figure.colorbar(mappable)
pyplot.figure()
pyplot.subplot(2, 2, 1)
pcolor(numpy.real(E[0][:, :]))
pyplot.subplot(2, 2, 2)
pcolor(numpy.real(E[1][:, :]))
pyplot.subplot(2, 2, 3)
pcolor(numpy.real(E[2][:, :]))
pyplot.subplot(2, 2, 4)
fig, axes = pyplot.subplots(2, 2)
pcolor(fig, axes[0][0], numpy.real(E[0]), 'Ex')
pcolor(fig, axes[0][1], numpy.real(E[1]), 'Ey')
pcolor(fig, axes[1][0], numpy.real(E[2]), 'Ez')
pyplot.show()

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@ -12,7 +12,7 @@ cd ~/projects/meanas
rm -rf _doc_mathimg
pdoc --pdf --force --template-dir pdoc_templates -o doc . > doc.md
pandoc --metadata=title:"meanas" --from=markdown+abbreviations --to=html --output=doc.htex --gladtex -s --css pdoc_templates/pdoc.css doc.md
gladtex -a -n -d _doc_mathimg -c white doc.htex
gladtex -a -n -d _doc_mathimg -c white -b black doc.htex
# Approach 3: html with gladtex
#pdoc3 --html --force --template-dir pdoc_templates -o doc .

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@ -6,12 +6,13 @@ See the readme or `import meanas; help(meanas)` for more info.
import pathlib
__version__ = '0.8'
__version__ = '0.9'
__author__ = 'Jan Petykiewicz'
try:
with open(pathlib.Path(__file__).parent / 'README.md', 'r') as f:
readme_path = pathlib.Path(__file__).parent / 'README.md'
with readme_path.open('r') as f:
__doc__ = f.read()
except Exception:
pass

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@ -1,12 +1,12 @@
"""
Solvers for eigenvalue / eigenvector problems
"""
from typing import Callable
from collections.abc import Callable
import numpy
from numpy.typing import NDArray, ArrayLike
from numpy.linalg import norm
from scipy import sparse # type: ignore
import scipy.sparse.linalg as spalg # type: ignore
from scipy import sparse
import scipy.sparse.linalg as spalg
def power_iteration(
@ -25,8 +25,9 @@ def power_iteration(
Returns:
(Largest-magnitude eigenvalue, Corresponding eigenvector estimate)
"""
rng = numpy.random.default_rng()
if guess_vector is None:
v = numpy.random.rand(operator.shape[0]) + 1j * numpy.random.rand(operator.shape[0])
v = rng.random(operator.shape[0]) + 1j * rng.random(operator.shape[0])
else:
v = guess_vector

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@ -1,4 +1,4 @@
"""
r"""
Tools for finite difference frequency-domain (FDFD) simulations and calculations.
These mostly involve picking a single frequency, then setting up and solving a
@ -19,71 +19,71 @@ Submodules:
From the "Frequency domain" section of `meanas.fdmath`, we have
$$
\\begin{aligned}
\\tilde{E}_{l, \\vec{r}} &= \\tilde{E}_{\\vec{r}} e^{-\\imath \\omega l \\Delta_t} \\\\
\\tilde{H}_{l - \\frac{1}{2}, \\vec{r} + \\frac{1}{2}} &= \\tilde{H}_{\\vec{r} + \\frac{1}{2}} e^{-\\imath \\omega (l - \\frac{1}{2}) \\Delta_t} \\\\
\\tilde{J}_{l, \\vec{r}} &= \\tilde{J}_{\\vec{r}} e^{-\\imath \\omega (l - \\frac{1}{2}) \\Delta_t} \\\\
\\tilde{M}_{l - \\frac{1}{2}, \\vec{r} + \\frac{1}{2}} &= \\tilde{M}_{\\vec{r} + \\frac{1}{2}} e^{-\\imath \\omega l \\Delta_t} \\\\
\\hat{\\nabla} \\times (\\mu^{-1}_{\\vec{r} + \\frac{1}{2}} \\cdot \\tilde{\\nabla} \\times \\tilde{E}_{\\vec{r}})
-\\Omega^2 \\epsilon_{\\vec{r}} \\cdot \\tilde{E}_{\\vec{r}} &= -\\imath \\Omega \\tilde{J}_{\\vec{r}} e^{\\imath \\omega \\Delta_t / 2} \\\\
\\Omega &= 2 \\sin(\\omega \\Delta_t / 2) / \\Delta_t
\\end{aligned}
\begin{aligned}
\tilde{E}_{l, \vec{r}} &= \tilde{E}_{\vec{r}} e^{-\imath \omega l \Delta_t} \\
\tilde{H}_{l - \frac{1}{2}, \vec{r} + \frac{1}{2}} &= \tilde{H}_{\vec{r} + \frac{1}{2}} e^{-\imath \omega (l - \frac{1}{2}) \Delta_t} \\
\tilde{J}_{l, \vec{r}} &= \tilde{J}_{\vec{r}} e^{-\imath \omega (l - \frac{1}{2}) \Delta_t} \\
\tilde{M}_{l - \frac{1}{2}, \vec{r} + \frac{1}{2}} &= \tilde{M}_{\vec{r} + \frac{1}{2}} e^{-\imath \omega l \Delta_t} \\
\hat{\nabla} \times (\mu^{-1}_{\vec{r} + \frac{1}{2}} \cdot \tilde{\nabla} \times \tilde{E}_{\vec{r}})
-\Omega^2 \epsilon_{\vec{r}} \cdot \tilde{E}_{\vec{r}} &= -\imath \Omega \tilde{J}_{\vec{r}} e^{\imath \omega \Delta_t / 2} \\
\Omega &= 2 \sin(\omega \Delta_t / 2) / \Delta_t
\end{aligned}
$$
resulting in
$$
\\begin{aligned}
\\tilde{\\partial}_t &\\Rightarrow -\\imath \\Omega e^{-\\imath \\omega \\Delta_t / 2}\\\\
\\hat{\\partial}_t &\\Rightarrow -\\imath \\Omega e^{ \\imath \\omega \\Delta_t / 2}\\\\
\\end{aligned}
\begin{aligned}
\tilde{\partial}_t &\Rightarrow -\imath \Omega e^{-\imath \omega \Delta_t / 2}\\
\hat{\partial}_t &\Rightarrow -\imath \Omega e^{ \imath \omega \Delta_t / 2}\\
\end{aligned}
$$
Maxwell's equations are then
$$
\\begin{aligned}
\\tilde{\\nabla} \\times \\tilde{E}_{\\vec{r}} &=
\\imath \\Omega e^{-\\imath \\omega \\Delta_t / 2} \\hat{B}_{\\vec{r} + \\frac{1}{2}}
- \\hat{M}_{\\vec{r} + \\frac{1}{2}} \\\\
\\hat{\\nabla} \\times \\hat{H}_{\\vec{r} + \\frac{1}{2}} &=
-\\imath \\Omega e^{ \\imath \\omega \\Delta_t / 2} \\tilde{D}_{\\vec{r}}
+ \\tilde{J}_{\\vec{r}} \\\\
\\tilde{\\nabla} \\cdot \\hat{B}_{\\vec{r} + \\frac{1}{2}} &= 0 \\\\
\\hat{\\nabla} \\cdot \\tilde{D}_{\\vec{r}} &= \\rho_{\\vec{r}}
\\end{aligned}
\begin{aligned}
\tilde{\nabla} \times \tilde{E}_{\vec{r}} &=
\imath \Omega e^{-\imath \omega \Delta_t / 2} \hat{B}_{\vec{r} + \frac{1}{2}}
- \hat{M}_{\vec{r} + \frac{1}{2}} \\
\hat{\nabla} \times \hat{H}_{\vec{r} + \frac{1}{2}} &=
-\imath \Omega e^{ \imath \omega \Delta_t / 2} \tilde{D}_{\vec{r}}
+ \tilde{J}_{\vec{r}} \\
\tilde{\nabla} \cdot \hat{B}_{\vec{r} + \frac{1}{2}} &= 0 \\
\hat{\nabla} \cdot \tilde{D}_{\vec{r}} &= \rho_{\vec{r}}
\end{aligned}
$$
With $\\Delta_t \\to 0$, this simplifies to
With $\Delta_t \to 0$, this simplifies to
$$
\\begin{aligned}
\\tilde{E}_{l, \\vec{r}} &\\to \\tilde{E}_{\\vec{r}} \\\\
\\tilde{H}_{l - \\frac{1}{2}, \\vec{r} + \\frac{1}{2}} &\\to \\tilde{H}_{\\vec{r} + \\frac{1}{2}} \\\\
\\tilde{J}_{l, \\vec{r}} &\\to \\tilde{J}_{\\vec{r}} \\\\
\\tilde{M}_{l - \\frac{1}{2}, \\vec{r} + \\frac{1}{2}} &\\to \\tilde{M}_{\\vec{r} + \\frac{1}{2}} \\\\
\\Omega &\\to \\omega \\\\
\\tilde{\\partial}_t &\\to -\\imath \\omega \\\\
\\hat{\\partial}_t &\\to -\\imath \\omega \\\\
\\end{aligned}
\begin{aligned}
\tilde{E}_{l, \vec{r}} &\to \tilde{E}_{\vec{r}} \\
\tilde{H}_{l - \frac{1}{2}, \vec{r} + \frac{1}{2}} &\to \tilde{H}_{\vec{r} + \frac{1}{2}} \\
\tilde{J}_{l, \vec{r}} &\to \tilde{J}_{\vec{r}} \\
\tilde{M}_{l - \frac{1}{2}, \vec{r} + \frac{1}{2}} &\to \tilde{M}_{\vec{r} + \frac{1}{2}} \\
\Omega &\to \omega \\
\tilde{\partial}_t &\to -\imath \omega \\
\hat{\partial}_t &\to -\imath \omega \\
\end{aligned}
$$
and then
$$
\\begin{aligned}
\\tilde{\\nabla} \\times \\tilde{E}_{\\vec{r}} &=
\\imath \\omega \\hat{B}_{\\vec{r} + \\frac{1}{2}}
- \\hat{M}_{\\vec{r} + \\frac{1}{2}} \\\\
\\hat{\\nabla} \\times \\hat{H}_{\\vec{r} + \\frac{1}{2}} &=
-\\imath \\omega \\tilde{D}_{\\vec{r}}
+ \\tilde{J}_{\\vec{r}} \\\\
\\end{aligned}
\begin{aligned}
\tilde{\nabla} \times \tilde{E}_{\vec{r}} &=
\imath \omega \hat{B}_{\vec{r} + \frac{1}{2}}
- \hat{M}_{\vec{r} + \frac{1}{2}} \\
\hat{\nabla} \times \hat{H}_{\vec{r} + \frac{1}{2}} &=
-\imath \omega \tilde{D}_{\vec{r}}
+ \tilde{J}_{\vec{r}} \\
\end{aligned}
$$
$$
\\hat{\\nabla} \\times (\\mu^{-1}_{\\vec{r} + \\frac{1}{2}} \\cdot \\tilde{\\nabla} \\times \\tilde{E}_{\\vec{r}})
-\\omega^2 \\epsilon_{\\vec{r}} \\cdot \\tilde{E}_{\\vec{r}} = -\\imath \\omega \\tilde{J}_{\\vec{r}} \\\\
\hat{\nabla} \times (\mu^{-1}_{\vec{r} + \frac{1}{2}} \cdot \tilde{\nabla} \times \tilde{E}_{\vec{r}})
-\omega^2 \epsilon_{\vec{r}} \cdot \tilde{E}_{\vec{r}} = -\imath \omega \tilde{J}_{\vec{r}} \\
$$
# TODO FDFD?
@ -91,5 +91,12 @@ $$
"""
from . import solvers, operators, functional, scpml, waveguide_2d, waveguide_3d
from . import (
solvers as solvers,
operators as operators,
functional as functional,
scpml as scpml,
waveguide_2d as waveguide_2d,
waveguide_3d as waveguide_3d,
)
# from . import farfield, bloch TODO

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@ -94,16 +94,17 @@ This module contains functions for generating and solving the
"""
from typing import Callable, Any, cast, Sequence
from typing import Any, cast
from collections.abc import Callable, Sequence
import logging
import numpy
from numpy import pi, real, trace
from numpy.fft import fftfreq
from numpy.typing import NDArray, ArrayLike
import scipy # type: ignore
import scipy.optimize # type: ignore
from scipy.linalg import norm # type: ignore
import scipy.sparse.linalg as spalg # type: ignore
import scipy
import scipy.optimize
from scipy.linalg import norm
import scipy.sparse.linalg as spalg
from ..fdmath import fdfield_t, cfdfield_t
@ -114,7 +115,6 @@ logger = logging.getLogger(__name__)
try:
import pyfftw.interfaces.numpy_fft # type: ignore
import pyfftw.interfaces # type: ignore
import multiprocessing
logger.info('Using pyfftw')
pyfftw.interfaces.cache.enable()
@ -155,7 +155,7 @@ def generate_kmn(
All are given in the xyz basis (e.g. `|k|[0,0,0] = norm(G_matrix @ k0)`).
"""
k0 = numpy.array(k0)
G_matrix = numpy.array(G_matrix, copy=False)
G_matrix = numpy.asarray(G_matrix)
Gi_grids = numpy.array(numpy.meshgrid(*(fftfreq(n, 1 / n) for n in shape[:3]), indexing='ij'))
Gi = numpy.moveaxis(Gi_grids, 0, -1)
@ -232,7 +232,7 @@ def maxwell_operator(
Raveled conv(1/mu_k, ik x conv(1/eps_k, ik x h_mn)), returned
and overwritten in-place of `h`.
"""
hin_m, hin_n = [hi.reshape(shape) for hi in numpy.split(h, 2)]
hin_m, hin_n = (hi.reshape(shape) for hi in numpy.split(h, 2))
#{d,e,h}_xyz fields are complex 3-fields in (1/x, 1/y, 1/z) basis
@ -303,12 +303,12 @@ def hmn_2_exyz(
k_mag, m, n = generate_kmn(k0, G_matrix, shape)
def operator(h: NDArray[numpy.complex128]) -> cfdfield_t:
hin_m, hin_n = [hi.reshape(shape) for hi in numpy.split(h, 2)]
hin_m, hin_n = (hi.reshape(shape) for hi in numpy.split(h, 2))
d_xyz = (n * hin_m
- m * hin_n) * k_mag # noqa: E128
# divide by epsilon
return numpy.array([ei for ei in numpy.moveaxis(ifftn(d_xyz, axes=range(3)) / epsilon, 3, 0)]) # TODO avoid copy
return numpy.moveaxis(ifftn(d_xyz, axes=range(3)) / epsilon, 3, 0)
return operator
@ -341,7 +341,7 @@ def hmn_2_hxyz(
_k_mag, m, n = generate_kmn(k0, G_matrix, shape)
def operator(h: NDArray[numpy.complex128]) -> cfdfield_t:
hin_m, hin_n = [hi.reshape(shape) for hi in numpy.split(h, 2)]
hin_m, hin_n = (hi.reshape(shape) for hi in numpy.split(h, 2))
h_xyz = (m * hin_m
+ n * hin_n) # noqa: E128
return numpy.array([ifftn(hi) for hi in numpy.moveaxis(h_xyz, 3, 0)])
@ -394,7 +394,7 @@ def inverse_maxwell_operator_approx(
Returns:
Raveled ik x conv(eps_k, ik x conv(mu_k, h_mn))
"""
hin_m, hin_n = [hi.reshape(shape) for hi in numpy.split(h, 2)]
hin_m, hin_n = (hi.reshape(shape) for hi in numpy.split(h, 2))
#{d,e,h}_xyz fields are complex 3-fields in (1/x, 1/y, 1/z) basis
@ -538,7 +538,7 @@ def eigsolve(
`(eigenvalues, eigenvectors)` where `eigenvalues[i]` corresponds to the
vector `eigenvectors[i, :]`
"""
k0 = numpy.array(k0, copy=False)
k0 = numpy.asarray(k0)
h_size = 2 * epsilon[0].size
@ -561,11 +561,12 @@ def eigsolve(
prev_theta = 0.5
D = numpy.zeros(shape=y_shape, dtype=complex)
rng = numpy.random.default_rng()
Z: NDArray[numpy.complex128]
if y0 is None:
Z = numpy.random.rand(*y_shape) + 1j * numpy.random.rand(*y_shape)
Z = rng.random(y_shape) + 1j * rng.random(y_shape)
else:
Z = numpy.array(y0, copy=False).T
Z = numpy.asarray(y0).T
while True:
Z *= num_modes / norm(Z)
@ -573,7 +574,7 @@ def eigsolve(
try:
U = numpy.linalg.inv(ZtZ)
except numpy.linalg.LinAlgError:
Z = numpy.random.rand(*y_shape) + 1j * numpy.random.rand(*y_shape)
Z = rng.random(y_shape) + 1j * rng.random(y_shape)
continue
trace_U = real(trace(U))
@ -646,8 +647,7 @@ def eigsolve(
Qi_memo: list[float | None] = [None, None]
def Qi_func(theta: float) -> float:
nonlocal Qi_memo
def Qi_func(theta: float, Qi_memo=Qi_memo, ZtZ=ZtZ, DtD=DtD, symZtD=symZtD) -> float: # noqa: ANN001
if Qi_memo[0] == theta:
return cast(float, Qi_memo[1])
@ -656,7 +656,7 @@ def eigsolve(
Q = c * c * ZtZ + s * s * DtD + 2 * s * c * symZtD
try:
Qi = numpy.linalg.inv(Q)
except numpy.linalg.LinAlgError:
except numpy.linalg.LinAlgError as err:
logger.info('taylor Qi')
# if c or s small, taylor expand
if c < 1e-4 * s and c != 0:
@ -666,12 +666,12 @@ def eigsolve(
ZtZi = numpy.linalg.inv(ZtZ)
Qi = ZtZi / (c * c) - 2 * s / (c * c * c) * (ZtZi @ (ZtZi @ symZtD).conj().T)
else:
raise Exception('Inexplicable singularity in trace_func')
raise Exception('Inexplicable singularity in trace_func') from err
Qi_memo[0] = theta
Qi_memo[1] = cast(float, Qi)
return cast(float, Qi)
def trace_func(theta: float) -> float:
def trace_func(theta: float, ZtAZ=ZtAZ, DtAD=DtAD, symZtAD=symZtAD) -> float: # noqa: ANN001
c = numpy.cos(theta)
s = numpy.sin(theta)
Qi = Qi_func(theta)
@ -680,15 +680,15 @@ def eigsolve(
return numpy.abs(trace)
if False:
def trace_deriv(theta):
def trace_deriv(theta, sgn: int = sgn, ZtAZ=ZtAZ, DtAD=DtAD, symZtD=symZtD, symZtAD=symZtAD, ZtZ=ZtZ, DtD=DtD): # noqa: ANN001
Qi = Qi_func(theta)
c2 = numpy.cos(2 * theta)
s2 = numpy.sin(2 * theta)
F = -0.5*s2 * (ZtAZ - DtAD) + c2 * symZtAD
F = -0.5 * s2 * (ZtAZ - DtAD) + c2 * symZtAD
trace_deriv = _rtrace_AtB(Qi, F)
G = Qi @ F.conj().T @ Qi.conj().T
H = -0.5*s2 * (ZtZ - DtD) + c2 * symZtD
H = -0.5 * s2 * (ZtZ - DtD) + c2 * symZtD
trace_deriv -= _rtrace_AtB(G, H)
trace_deriv *= 2
@ -696,12 +696,12 @@ def eigsolve(
U_sZtD = U @ symZtD
dE = 2.0 * (_rtrace_AtB(U, symZtAD) -
_rtrace_AtB(ZtAZU, U_sZtD))
dE = 2.0 * (_rtrace_AtB(U, symZtAD)
- _rtrace_AtB(ZtAZU, U_sZtD))
d2E = 2 * (_rtrace_AtB(U, DtAD) -
_rtrace_AtB(ZtAZU, U @ (DtD - 4 * symZtD @ U_sZtD)) -
4 * _rtrace_AtB(U, symZtAD @ U_sZtD))
d2E = 2 * (_rtrace_AtB(U, DtAD)
- _rtrace_AtB(ZtAZU, U @ (DtD - 4 * symZtD @ U_sZtD))
- 4 * _rtrace_AtB(U, symZtAD @ U_sZtD))
# Newton-Raphson to find a root of the first derivative:
theta = -dE / d2E
@ -781,7 +781,7 @@ def linmin(x_guess, f0, df0, x_max, f_tol=0.1, df_tol=min(tolerance, 1e-6), x_to
x_min, x_max, isave, dsave)
for i in range(int(1e6)):
if task != 'F':
logging.info('search converged in {} iterations'.format(i))
logging.info(f'search converged in {i} iterations')
break
fx = f(x, dfx)
x, fx, dfx, task = minpack2.dsrch(x, fx, dfx, f_tol, df_tol, x_tol, task,

View File

@ -1,7 +1,8 @@
"""
Functions for performing near-to-farfield transformation (and the reverse).
"""
from typing import Any, Sequence, cast
from typing import Any, cast
from collections.abc import Sequence
import numpy
from numpy.fft import fft2, fftshift, fftfreq, ifft2, ifftshift
from numpy import pi

View File

@ -5,7 +5,7 @@ Functional versions of many FDFD operators. These can be useful for performing
The functions generated here expect `cfdfield_t` inputs with shape (3, X, Y, Z),
e.g. E = [E_x, E_y, E_z] where each (complex) component has shape (X, Y, Z)
"""
from typing import Callable
from collections.abc import Callable
import numpy
from ..fdmath import dx_lists_t, fdfield_t, cfdfield_t, cfdfield_updater_t
@ -47,7 +47,6 @@ def e_full(
if mu is None:
return op_1
else:
return op_mu
@ -84,7 +83,6 @@ def eh_full(
if mu is None:
return op_1
else:
return op_mu
@ -116,7 +114,6 @@ def e2h(
if mu is None:
return e2h_1_1
else:
return e2h_mu
@ -151,7 +148,6 @@ def m2j(
if mu is None:
return m2j_1
else:
return m2j_mu
@ -189,10 +185,10 @@ def e_tfsf_source(
def poynting_e_cross_h(dxes: dx_lists_t) -> Callable[[cfdfield_t, cfdfield_t], cfdfield_t]:
"""
r"""
Generates a function that takes the single-frequency `E` and `H` fields
and calculates the cross product `E` x `H` = $E \\times H$ as required
for the Poynting vector, $S = E \\times H$
and calculates the cross product `E` x `H` = $E \times H$ as required
for the Poynting vector, $S = E \times H$
Note:
This function also shifts the input `E` field by one cell as required
@ -200,7 +196,7 @@ def poynting_e_cross_h(dxes: dx_lists_t) -> Callable[[cfdfield_t, cfdfield_t], c
Note:
If `E` and `H` are peak amplitudes as assumed elsewhere in this code,
the time-average of the poynting vector is `<S> = Re(S)/2 = Re(E x H) / 2`.
the time-average of the poynting vector is `<S> = Re(S)/2 = Re(E x H*) / 2`.
The factor of `1/2` can be omitted if root-mean-square quantities are used
instead.

View File

@ -28,7 +28,7 @@ The following operators are included:
"""
import numpy
import scipy.sparse as sparse # type: ignore
from scipy import sparse
from ..fdmath import vec, dx_lists_t, vfdfield_t, vcfdfield_t
from ..fdmath.operators import shift_with_mirror, shift_circ, curl_forward, curl_back
@ -45,14 +45,14 @@ def e_full(
pec: vfdfield_t | None = None,
pmc: vfdfield_t | None = None,
) -> sparse.spmatrix:
"""
r"""
Wave operator
$$ \\nabla \\times (\\frac{1}{\\mu} \\nabla \\times) - \\Omega^2 \\epsilon $$
$$ \nabla \times (\frac{1}{\mu} \nabla \times) - \Omega^2 \epsilon $$
del x (1/mu * del x) - omega**2 * epsilon
for use with the E-field, with wave equation
$$ (\\nabla \\times (\\frac{1}{\\mu} \\nabla \\times) - \\Omega^2 \\epsilon) E = -\\imath \\omega J $$
$$ (\nabla \times (\frac{1}{\mu} \nabla \times) - \Omega^2 \epsilon) E = -\imath \omega J $$
(del x (1/mu * del x) - omega**2 * epsilon) E = -i * omega * J
@ -131,14 +131,14 @@ def h_full(
pec: vfdfield_t | None = None,
pmc: vfdfield_t | None = None,
) -> sparse.spmatrix:
"""
r"""
Wave operator
$$ \\nabla \\times (\\frac{1}{\\epsilon} \\nabla \\times) - \\omega^2 \\mu $$
$$ \nabla \times (\frac{1}{\epsilon} \nabla \times) - \omega^2 \mu $$
del x (1/epsilon * del x) - omega**2 * mu
for use with the H-field, with wave equation
$$ (\\nabla \\times (\\frac{1}{\\epsilon} \\nabla \\times) - \\omega^2 \\mu) E = \\imath \\omega M $$
$$ (\nabla \times (\frac{1}{\epsilon} \nabla \times) - \omega^2 \mu) E = \imath \omega M $$
(del x (1/epsilon * del x) - omega**2 * mu) E = i * omega * M
@ -188,28 +188,28 @@ def eh_full(
pec: vfdfield_t | None = None,
pmc: vfdfield_t | None = None,
) -> sparse.spmatrix:
"""
r"""
Wave operator for `[E, H]` field representation. This operator implements Maxwell's
equations without cancelling out either E or H. The operator is
$$ \\begin{bmatrix}
-\\imath \\omega \\epsilon & \\nabla \\times \\\\
\\nabla \\times & \\imath \\omega \\mu
\\end{bmatrix} $$
$$ \begin{bmatrix}
-\imath \omega \epsilon & \nabla \times \\
\nabla \times & \imath \omega \mu
\end{bmatrix} $$
[[-i * omega * epsilon, del x ],
[del x, i * omega * mu]]
for use with a field vector of the form `cat(vec(E), vec(H))`:
$$ \\begin{bmatrix}
-\\imath \\omega \\epsilon & \\nabla \\times \\\\
\\nabla \\times & \\imath \\omega \\mu
\\end{bmatrix}
\\begin{bmatrix} E \\\\
$$ \begin{bmatrix}
-\imath \omega \epsilon & \nabla \times \\
\nabla \times & \imath \omega \mu
\end{bmatrix}
\begin{bmatrix} E \\
H
\\end{bmatrix}
= \\begin{bmatrix} J \\\\
\end{bmatrix}
= \begin{bmatrix} J \\
-M
\\end{bmatrix} $$
\end{bmatrix} $$
Args:
omega: Angular frequency of the simulation
@ -321,17 +321,18 @@ def poynting_e_cross(e: vcfdfield_t, dxes: dx_lists_t) -> sparse.spmatrix:
"""
shape = [len(dx) for dx in dxes[0]]
fx, fy, fz = [shift_circ(i, shape, 1) for i in range(3)]
fx, fy, fz = (shift_circ(i, shape, 1) for i in range(3))
dxag = [dx.ravel(order='C') for dx in numpy.meshgrid(*dxes[0], indexing='ij')]
Ex, Ey, Ez = [ei * da for ei, da in zip(numpy.split(e, 3), dxag)]
dxbg = [dx.ravel(order='C') for dx in numpy.meshgrid(*dxes[1], indexing='ij')]
Ex, Ey, Ez = (ei * da for ei, da in zip(numpy.split(e, 3), dxag, strict=True))
block_diags = [[ None, fx @ -Ez, fx @ Ey],
[ fy @ Ez, None, fy @ -Ex],
[ fz @ -Ey, fz @ Ex, None]]
block_matrix = sparse.bmat([[sparse.diags(x) if x is not None else None for x in row]
for row in block_diags])
P = block_matrix @ sparse.diags(numpy.concatenate(dxag))
P = block_matrix @ sparse.diags(numpy.concatenate(dxbg))
return P
@ -348,11 +349,11 @@ def poynting_h_cross(h: vcfdfield_t, dxes: dx_lists_t) -> sparse.spmatrix:
"""
shape = [len(dx) for dx in dxes[0]]
fx, fy, fz = [shift_circ(i, shape, 1) for i in range(3)]
fx, fy, fz = (shift_circ(i, shape, 1) for i in range(3))
dxag = [dx.ravel(order='C') for dx in numpy.meshgrid(*dxes[0], indexing='ij')]
dxbg = [dx.ravel(order='C') for dx in numpy.meshgrid(*dxes[1], indexing='ij')]
Hx, Hy, Hz = [sparse.diags(hi * db) for hi, db in zip(numpy.split(h, 3), dxbg)]
Hx, Hy, Hz = (sparse.diags(hi * db) for hi, db in zip(numpy.split(h, 3), dxbg, strict=True))
P = (sparse.bmat(
[[ None, -Hz @ fx, Hy @ fx],

View File

@ -2,7 +2,7 @@
Functions for creating stretched coordinate perfectly matched layer (PML) absorbers.
"""
from typing import Sequence, Callable
from collections.abc import Sequence, Callable
import numpy
from numpy.typing import NDArray

View File

@ -2,13 +2,14 @@
Solvers and solver interface for FDFD problems.
"""
from typing import Callable, Dict, Any, Optional
from typing import Any
from collections.abc import Callable
import logging
import numpy
from numpy.typing import ArrayLike, NDArray
from numpy.linalg import norm
import scipy.sparse.linalg # type: ignore
import scipy.sparse.linalg
from ..fdmath import dx_lists_t, vfdfield_t, vcfdfield_t
from . import operators
@ -43,7 +44,8 @@ def _scipy_qmr(
nonlocal ii
ii += 1
if ii % 100 == 0:
logger.info('Solver residual at iteration {} : {}'.format(ii, norm(A @ xk - b)))
cur_norm = norm(A @ xk - b)
logger.info(f'Solver residual at iteration {ii} : {cur_norm}')
if 'callback' in kwargs:
def augmented_callback(xk: ArrayLike) -> None:
@ -67,12 +69,12 @@ def generic(
dxes: dx_lists_t,
J: vcfdfield_t,
epsilon: vfdfield_t,
mu: Optional[vfdfield_t] = None,
pec: Optional[vfdfield_t] = None,
pmc: Optional[vfdfield_t] = None,
mu: vfdfield_t | None = None,
pec: vfdfield_t | None = None,
pmc: vfdfield_t | None = None,
adjoint: bool = False,
matrix_solver: Callable[..., ArrayLike] = _scipy_qmr,
matrix_solver_opts: Optional[Dict[str, Any]] = None,
matrix_solver_opts: dict[str, Any] | None = None,
) -> vcfdfield_t:
"""
Conjugate gradient FDFD solver using CSR sparse matrices.

View File

@ -1,4 +1,4 @@
"""
r"""
Operators and helper functions for waveguides with unchanging cross-section.
The propagation direction is chosen to be along the z axis, and all fields
@ -12,166 +12,166 @@ As the z-dependence is known, all the functions in this file assume a 2D grid
Consider Maxwell's equations in continuous space, in the frequency domain. Assuming
a structure with some (x, y) cross-section extending uniformly into the z dimension,
with a diagonal $\\epsilon$ tensor, we have
with a diagonal $\epsilon$ tensor, we have
$$
\\begin{aligned}
\\nabla \\times \\vec{E}(x, y, z) &= -\\imath \\omega \\mu \\vec{H} \\\\
\\nabla \\times \\vec{H}(x, y, z) &= \\imath \\omega \\epsilon \\vec{E} \\\\
\\vec{E}(x,y,z) = (\\vec{E}_t(x, y) + E_z(x, y)\\vec{z}) e^{-\\gamma z} \\\\
\\vec{H}(x,y,z) = (\\vec{H}_t(x, y) + H_z(x, y)\\vec{z}) e^{-\\gamma z} \\\\
\\end{aligned}
\begin{aligned}
\nabla \times \vec{E}(x, y, z) &= -\imath \omega \mu \vec{H} \\
\nabla \times \vec{H}(x, y, z) &= \imath \omega \epsilon \vec{E} \\
\vec{E}(x,y,z) &= (\vec{E}_t(x, y) + E_z(x, y)\vec{z}) e^{-\gamma z} \\
\vec{H}(x,y,z) &= (\vec{H}_t(x, y) + H_z(x, y)\vec{z}) e^{-\gamma z} \\
\end{aligned}
$$
Expanding the first two equations into vector components, we get
$$
\\begin{aligned}
-\\imath \\omega \\mu_{xx} H_x &= \\partial_y E_z - \\partial_z E_y \\\\
-\\imath \\omega \\mu_{yy} H_y &= \\partial_z E_x - \\partial_x E_z \\\\
-\\imath \\omega \\mu_{zz} H_z &= \\partial_x E_y - \\partial_y E_x \\\\
\\imath \\omega \\epsilon_{xx} E_x &= \\partial_y H_z - \\partial_z H_y \\\\
\\imath \\omega \\epsilon_{yy} E_y &= \\partial_z H_x - \\partial_x H_z \\\\
\\imath \\omega \\epsilon_{zz} E_z &= \\partial_x H_y - \\partial_y H_x \\\\
\\end{aligned}
\begin{aligned}
-\imath \omega \mu_{xx} H_x &= \partial_y E_z - \partial_z E_y \\
-\imath \omega \mu_{yy} H_y &= \partial_z E_x - \partial_x E_z \\
-\imath \omega \mu_{zz} H_z &= \partial_x E_y - \partial_y E_x \\
\imath \omega \epsilon_{xx} E_x &= \partial_y H_z - \partial_z H_y \\
\imath \omega \epsilon_{yy} E_y &= \partial_z H_x - \partial_x H_z \\
\imath \omega \epsilon_{zz} E_z &= \partial_x H_y - \partial_y H_x \\
\end{aligned}
$$
Substituting in our expressions for $\\vec{E}$, $\\vec{H}$ and discretizing:
Substituting in our expressions for $\vec{E}$, $\vec{H}$ and discretizing:
$$
\\begin{aligned}
-\\imath \\omega \\mu_{xx} H_x &= \\tilde{\\partial}_y E_z + \\gamma E_y \\\\
-\\imath \\omega \\mu_{yy} H_y &= -\\gamma E_x - \\tilde{\\partial}_x E_z \\\\
-\\imath \\omega \\mu_{zz} H_z &= \\tilde{\\partial}_x E_y - \\tilde{\\partial}_y E_x \\\\
\\imath \\omega \\epsilon_{xx} E_x &= \\hat{\\partial}_y H_z + \\gamma H_y \\\\
\\imath \\omega \\epsilon_{yy} E_y &= -\\gamma H_x - \\hat{\\partial}_x H_z \\\\
\\imath \\omega \\epsilon_{zz} E_z &= \\hat{\\partial}_x H_y - \\hat{\\partial}_y H_x \\\\
\\end{aligned}
\begin{aligned}
-\imath \omega \mu_{xx} H_x &= \tilde{\partial}_y E_z + \gamma E_y \\
-\imath \omega \mu_{yy} H_y &= -\gamma E_x - \tilde{\partial}_x E_z \\
-\imath \omega \mu_{zz} H_z &= \tilde{\partial}_x E_y - \tilde{\partial}_y E_x \\
\imath \omega \epsilon_{xx} E_x &= \hat{\partial}_y H_z + \gamma H_y \\
\imath \omega \epsilon_{yy} E_y &= -\gamma H_x - \hat{\partial}_x H_z \\
\imath \omega \epsilon_{zz} E_z &= \hat{\partial}_x H_y - \hat{\partial}_y H_x \\
\end{aligned}
$$
Rewrite the last three equations as
$$
\\begin{aligned}
\\gamma H_y &= \\imath \\omega \\epsilon_{xx} E_x - \\hat{\\partial}_y H_z \\\\
\\gamma H_x &= -\\imath \\omega \\epsilon_{yy} E_y - \\hat{\\partial}_x H_z \\\\
\\imath \\omega E_z &= \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x H_y - \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y H_x \\\\
\\end{aligned}
\begin{aligned}
\gamma H_y &= \imath \omega \epsilon_{xx} E_x - \hat{\partial}_y H_z \\
\gamma H_x &= -\imath \omega \epsilon_{yy} E_y - \hat{\partial}_x H_z \\
\imath \omega E_z &= \frac{1}{\epsilon_{zz}} \hat{\partial}_x H_y - \frac{1}{\epsilon_{zz}} \hat{\partial}_y H_x \\
\end{aligned}
$$
Now apply $\\gamma \\tilde{\\partial}_x$ to the last equation,
then substitute in for $\\gamma H_x$ and $\\gamma H_y$:
Now apply $\gamma \tilde{\partial}_x$ to the last equation,
then substitute in for $\gamma H_x$ and $\gamma H_y$:
$$
\\begin{aligned}
\\gamma \\tilde{\\partial}_x \\imath \\omega E_z &= \\gamma \\tilde{\\partial}_x \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x H_y
- \\gamma \\tilde{\\partial}_x \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y H_x \\\\
&= \\tilde{\\partial}_x \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x ( \\imath \\omega \\epsilon_{xx} E_x - \\hat{\\partial}_y H_z)
- \\tilde{\\partial}_x \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y (-\\imath \\omega \\epsilon_{yy} E_y - \\hat{\\partial}_x H_z) \\\\
&= \\tilde{\\partial}_x \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x ( \\imath \\omega \\epsilon_{xx} E_x)
- \\tilde{\\partial}_x \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y (-\\imath \\omega \\epsilon_{yy} E_y) \\\\
\\gamma \\tilde{\\partial}_x E_z &= \\tilde{\\partial}_x \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x (\\epsilon_{xx} E_x)
+ \\tilde{\\partial}_x \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y (\\epsilon_{yy} E_y) \\\\
\\end{aligned}
\begin{aligned}
\gamma \tilde{\partial}_x \imath \omega E_z &= \gamma \tilde{\partial}_x \frac{1}{\epsilon_{zz}} \hat{\partial}_x H_y
- \gamma \tilde{\partial}_x \frac{1}{\epsilon_{zz}} \hat{\partial}_y H_x \\
&= \tilde{\partial}_x \frac{1}{\epsilon_{zz}} \hat{\partial}_x ( \imath \omega \epsilon_{xx} E_x - \hat{\partial}_y H_z)
- \tilde{\partial}_x \frac{1}{\epsilon_{zz}} \hat{\partial}_y (-\imath \omega \epsilon_{yy} E_y - \hat{\partial}_x H_z) \\
&= \tilde{\partial}_x \frac{1}{\epsilon_{zz}} \hat{\partial}_x ( \imath \omega \epsilon_{xx} E_x)
- \tilde{\partial}_x \frac{1}{\epsilon_{zz}} \hat{\partial}_y (-\imath \omega \epsilon_{yy} E_y) \\
\gamma \tilde{\partial}_x E_z &= \tilde{\partial}_x \frac{1}{\epsilon_{zz}} \hat{\partial}_x (\epsilon_{xx} E_x)
+ \tilde{\partial}_x \frac{1}{\epsilon_{zz}} \hat{\partial}_y (\epsilon_{yy} E_y) \\
\end{aligned}
$$
With a similar approach (but using $\\gamma \\tilde{\\partial}_y$ instead), we can get
With a similar approach (but using $\gamma \tilde{\partial}_y$ instead), we can get
$$
\\begin{aligned}
\\gamma \\tilde{\\partial}_y E_z &= \\tilde{\\partial}_y \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x (\\epsilon_{xx} E_x)
+ \\tilde{\\partial}_y \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y (\\epsilon_{yy} E_y) \\\\
\\end{aligned}
\begin{aligned}
\gamma \tilde{\partial}_y E_z &= \tilde{\partial}_y \frac{1}{\epsilon_{zz}} \hat{\partial}_x (\epsilon_{xx} E_x)
+ \tilde{\partial}_y \frac{1}{\epsilon_{zz}} \hat{\partial}_y (\epsilon_{yy} E_y) \\
\end{aligned}
$$
We can combine this equation for $\\gamma \\tilde{\\partial}_y E_z$ with
the unused $\\imath \\omega \\mu_{xx} H_x$ and $\\imath \\omega \\mu_{yy} H_y$ equations to get
We can combine this equation for $\gamma \tilde{\partial}_y E_z$ with
the unused $\imath \omega \mu_{xx} H_x$ and $\imath \omega \mu_{yy} H_y$ equations to get
$$
\\begin{aligned}
-\\imath \\omega \\mu_{xx} \\gamma H_x &= \\gamma^2 E_y + \\gamma \\tilde{\\partial}_y E_z \\\\
-\\imath \\omega \\mu_{xx} \\gamma H_x &= \\gamma^2 E_y + \\tilde{\\partial}_y (
\\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x (\\epsilon_{xx} E_x)
+ \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y (\\epsilon_{yy} E_y)
)\\\\
\\end{aligned}
\begin{aligned}
-\imath \omega \mu_{xx} \gamma H_x &= \gamma^2 E_y + \gamma \tilde{\partial}_y E_z \\
-\imath \omega \mu_{xx} \gamma H_x &= \gamma^2 E_y + \tilde{\partial}_y (
\frac{1}{\epsilon_{zz}} \hat{\partial}_x (\epsilon_{xx} E_x)
+ \frac{1}{\epsilon_{zz}} \hat{\partial}_y (\epsilon_{yy} E_y)
)\\
\end{aligned}
$$
and
$$
\\begin{aligned}
-\\imath \\omega \\mu_{yy} \\gamma H_y &= -\\gamma^2 E_x - \\gamma \\tilde{\\partial}_x E_z \\\\
-\\imath \\omega \\mu_{yy} \\gamma H_y &= -\\gamma^2 E_x - \\tilde{\\partial}_x (
\\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x (\\epsilon_{xx} E_x)
+ \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y (\\epsilon_{yy} E_y)
)\\\\
\\end{aligned}
\begin{aligned}
-\imath \omega \mu_{yy} \gamma H_y &= -\gamma^2 E_x - \gamma \tilde{\partial}_x E_z \\
-\imath \omega \mu_{yy} \gamma H_y &= -\gamma^2 E_x - \tilde{\partial}_x (
\frac{1}{\epsilon_{zz}} \hat{\partial}_x (\epsilon_{xx} E_x)
+ \frac{1}{\epsilon_{zz}} \hat{\partial}_y (\epsilon_{yy} E_y)
)\\
\end{aligned}
$$
However, based on our rewritten equation for $\\gamma H_x$ and the so-far unused
equation for $\\imath \\omega \\mu_{zz} H_z$ we can also write
However, based on our rewritten equation for $\gamma H_x$ and the so-far unused
equation for $\imath \omega \mu_{zz} H_z$ we can also write
$$
\\begin{aligned}
-\\imath \\omega \\mu_{xx} (\\gamma H_x) &= -\\imath \\omega \\mu_{xx} (-\\imath \\omega \\epsilon_{yy} E_y - \\hat{\\partial}_x H_z) \\\\
&= -\\omega^2 \\mu_{xx} \\epsilon_{yy} E_y
+\\imath \\omega \\mu_{xx} \\hat{\\partial}_x (
\\frac{1}{-\\imath \\omega \\mu_{zz}} (\\tilde{\\partial}_x E_y - \\tilde{\\partial}_y E_x)) \\\\
&= -\\omega^2 \\mu_{xx} \\epsilon_{yy} E_y
-\\mu_{xx} \\hat{\\partial}_x \\frac{1}{\\mu_{zz}} (\\tilde{\\partial}_x E_y - \\tilde{\\partial}_y E_x) \\\\
\\end{aligned}
\begin{aligned}
-\imath \omega \mu_{xx} (\gamma H_x) &= -\imath \omega \mu_{xx} (-\imath \omega \epsilon_{yy} E_y - \hat{\partial}_x H_z) \\
&= -\omega^2 \mu_{xx} \epsilon_{yy} E_y
+\imath \omega \mu_{xx} \hat{\partial}_x (
\frac{1}{-\imath \omega \mu_{zz}} (\tilde{\partial}_x E_y - \tilde{\partial}_y E_x)) \\
&= -\omega^2 \mu_{xx} \epsilon_{yy} E_y
-\mu_{xx} \hat{\partial}_x \frac{1}{\mu_{zz}} (\tilde{\partial}_x E_y - \tilde{\partial}_y E_x) \\
\end{aligned}
$$
and, similarly,
$$
\\begin{aligned}
-\\imath \\omega \\mu_{yy} (\\gamma H_y) &= \\omega^2 \\mu_{yy} \\epsilon_{xx} E_x
+\\mu_{yy} \\hat{\\partial}_y \\frac{1}{\\mu_{zz}} (\\tilde{\\partial}_x E_y - \\tilde{\\partial}_y E_x) \\\\
\\end{aligned}
\begin{aligned}
-\imath \omega \mu_{yy} (\gamma H_y) &= \omega^2 \mu_{yy} \epsilon_{xx} E_x
+\mu_{yy} \hat{\partial}_y \frac{1}{\mu_{zz}} (\tilde{\partial}_x E_y - \tilde{\partial}_y E_x) \\
\end{aligned}
$$
By combining both pairs of expressions, we get
$$
\\begin{aligned}
-\\gamma^2 E_x - \\tilde{\\partial}_x (
\\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x (\\epsilon_{xx} E_x)
+ \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y (\\epsilon_{yy} E_y)
) &= \\omega^2 \\mu_{yy} \\epsilon_{xx} E_x
+\\mu_{yy} \\hat{\\partial}_y \\frac{1}{\\mu_{zz}} (\\tilde{\\partial}_x E_y - \\tilde{\\partial}_y E_x) \\\\
\\gamma^2 E_y + \\tilde{\\partial}_y (
\\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_x (\\epsilon_{xx} E_x)
+ \\frac{1}{\\epsilon_{zz}} \\hat{\\partial}_y (\\epsilon_{yy} E_y)
) &= -\\omega^2 \\mu_{xx} \\epsilon_{yy} E_y
-\\mu_{xx} \\hat{\\partial}_x \\frac{1}{\\mu_{zz}} (\\tilde{\\partial}_x E_y - \\tilde{\\partial}_y E_x) \\\\
\\end{aligned}
\begin{aligned}
-\gamma^2 E_x - \tilde{\partial}_x (
\frac{1}{\epsilon_{zz}} \hat{\partial}_x (\epsilon_{xx} E_x)
+ \frac{1}{\epsilon_{zz}} \hat{\partial}_y (\epsilon_{yy} E_y)
) &= \omega^2 \mu_{yy} \epsilon_{xx} E_x
+\mu_{yy} \hat{\partial}_y \frac{1}{\mu_{zz}} (\tilde{\partial}_x E_y - \tilde{\partial}_y E_x) \\
\gamma^2 E_y + \tilde{\partial}_y (
\frac{1}{\epsilon_{zz}} \hat{\partial}_x (\epsilon_{xx} E_x)
+ \frac{1}{\epsilon_{zz}} \hat{\partial}_y (\epsilon_{yy} E_y)
) &= -\omega^2 \mu_{xx} \epsilon_{yy} E_y
-\mu_{xx} \hat{\partial}_x \frac{1}{\mu_{zz}} (\tilde{\partial}_x E_y - \tilde{\partial}_y E_x) \\
\end{aligned}
$$
Using these, we can construct the eigenvalue problem
$$
\\beta^2 \\begin{bmatrix} E_x \\\\
E_y \\end{bmatrix} =
(\\omega^2 \\begin{bmatrix} \\mu_{yy} \\epsilon_{xx} & 0 \\\\
0 & \\mu_{xx} \\epsilon_{yy} \\end{bmatrix} +
\\begin{bmatrix} -\\mu_{yy} \\hat{\\partial}_y \\\\
\\mu_{xx} \\hat{\\partial}_x \\end{bmatrix} \\mu_{zz}^{-1}
\\begin{bmatrix} -\\tilde{\\partial}_y & \\tilde{\\partial}_x \\end{bmatrix} +
\\begin{bmatrix} \\tilde{\\partial}_x \\\\
\\tilde{\\partial}_y \\end{bmatrix} \\epsilon_{zz}^{-1}
\\begin{bmatrix} \\hat{\\partial}_x \\epsilon_{xx} & \\hat{\\partial}_y \\epsilon_{yy} \\end{bmatrix})
\\begin{bmatrix} E_x \\\\
E_y \\end{bmatrix}
\beta^2 \begin{bmatrix} E_x \\
E_y \end{bmatrix} =
(\omega^2 \begin{bmatrix} \mu_{yy} \epsilon_{xx} & 0 \\
0 & \mu_{xx} \epsilon_{yy} \end{bmatrix} +
\begin{bmatrix} -\mu_{yy} \hat{\partial}_y \\
\mu_{xx} \hat{\partial}_x \end{bmatrix} \mu_{zz}^{-1}
\begin{bmatrix} -\tilde{\partial}_y & \tilde{\partial}_x \end{bmatrix} +
\begin{bmatrix} \tilde{\partial}_x \\
\tilde{\partial}_y \end{bmatrix} \epsilon_{zz}^{-1}
\begin{bmatrix} \hat{\partial}_x \epsilon_{xx} & \hat{\partial}_y \epsilon_{yy} \end{bmatrix})
\begin{bmatrix} E_x \\
E_y \end{bmatrix}
$$
where $\\gamma = \\imath\\beta$. In the literature, $\\beta$ is usually used to denote
where $\gamma = \imath\beta$. In the literature, $\beta$ is usually used to denote
the lossless/real part of the propagation constant, but in `meanas` it is allowed to
be complex.
An equivalent eigenvalue problem can be formed using the $H_x$ and $H_y$ fields, if those are more convenient.
Note that $E_z$ was never discretized, so $\\gamma$ and $\\beta$ will need adjustment
Note that $E_z$ was never discretized, so $\gamma$ and $\beta$ will need adjustment
to account for numerical dispersion if the result is introduced into a space with a discretized z-axis.
@ -182,10 +182,10 @@ from typing import Any
import numpy
from numpy.typing import NDArray, ArrayLike
from numpy.linalg import norm
import scipy.sparse as sparse # type: ignore
from scipy import sparse
from ..fdmath.operators import deriv_forward, deriv_back, cross
from ..fdmath import unvec, dx_lists_t, vfdfield_t, vcfdfield_t
from ..fdmath import vec, unvec, dx_lists_t, vfdfield_t, vcfdfield_t
from ..eigensolvers import signed_eigensolve, rayleigh_quotient_iteration
@ -198,7 +198,7 @@ def operator_e(
epsilon: vfdfield_t,
mu: vfdfield_t | None = None,
) -> sparse.spmatrix:
"""
r"""
Waveguide operator of the form
omega**2 * mu * epsilon +
@ -210,18 +210,18 @@ def operator_e(
More precisely, the operator is
$$
\\omega^2 \\begin{bmatrix} \\mu_{yy} \\epsilon_{xx} & 0 \\\\
0 & \\mu_{xx} \\epsilon_{yy} \\end{bmatrix} +
\\begin{bmatrix} -\\mu_{yy} \\hat{\\partial}_y \\\\
\\mu_{xx} \\hat{\\partial}_x \\end{bmatrix} \\mu_{zz}^{-1}
\\begin{bmatrix} -\\tilde{\\partial}_y & \\tilde{\\partial}_x \\end{bmatrix} +
\\begin{bmatrix} \\tilde{\\partial}_x \\\\
\\tilde{\\partial}_y \\end{bmatrix} \\epsilon_{zz}^{-1}
\\begin{bmatrix} \\hat{\\partial}_x \\epsilon_{xx} & \\hat{\\partial}_y \\epsilon_{yy} \\end{bmatrix}
\omega^2 \begin{bmatrix} \mu_{yy} \epsilon_{xx} & 0 \\
0 & \mu_{xx} \epsilon_{yy} \end{bmatrix} +
\begin{bmatrix} -\mu_{yy} \hat{\partial}_y \\
\mu_{xx} \hat{\partial}_x \end{bmatrix} \mu_{zz}^{-1}
\begin{bmatrix} -\tilde{\partial}_y & \tilde{\partial}_x \end{bmatrix} +
\begin{bmatrix} \tilde{\partial}_x \\
\tilde{\partial}_y \end{bmatrix} \epsilon_{zz}^{-1}
\begin{bmatrix} \hat{\partial}_x \epsilon_{xx} & \hat{\partial}_y \epsilon_{yy} \end{bmatrix}
$$
$\\tilde{\\partial}_x$ and $\\hat{\\partial}_x$ are the forward and backward derivatives along x,
and each $\\epsilon_{xx}$, $\\mu_{yy}$, etc. is a diagonal matrix containing the vectorized material
$\tilde{\partial}_x$ and $\hat{\partial}_x$ are the forward and backward derivatives along x,
and each $\epsilon_{xx}$, $\mu_{yy}$, etc. is a diagonal matrix containing the vectorized material
property distribution.
This operator can be used to form an eigenvalue problem of the form
@ -253,9 +253,11 @@ def operator_e(
mu_yx = sparse.diags(numpy.hstack((mu_parts[1], mu_parts[0])))
mu_z_inv = sparse.diags(1 / mu_parts[2])
op = omega * omega * mu_yx @ eps_xy + \
mu_yx @ sparse.vstack((-Dby, Dbx)) @ mu_z_inv @ sparse.hstack((-Dfy, Dfx)) + \
sparse.vstack((Dfx, Dfy)) @ eps_z_inv @ sparse.hstack((Dbx, Dby)) @ eps_xy
op = (
omega * omega * mu_yx @ eps_xy
+ mu_yx @ sparse.vstack((-Dby, Dbx)) @ mu_z_inv @ sparse.hstack((-Dfy, Dfx))
+ sparse.vstack((Dfx, Dfy)) @ eps_z_inv @ sparse.hstack((Dbx, Dby)) @ eps_xy
)
return op
@ -265,7 +267,7 @@ def operator_h(
epsilon: vfdfield_t,
mu: vfdfield_t | None = None,
) -> sparse.spmatrix:
"""
r"""
Waveguide operator of the form
omega**2 * epsilon * mu +
@ -277,18 +279,18 @@ def operator_h(
More precisely, the operator is
$$
\\omega^2 \\begin{bmatrix} \\epsilon_{yy} \\mu_{xx} & 0 \\\\
0 & \\epsilon_{xx} \\mu_{yy} \\end{bmatrix} +
\\begin{bmatrix} -\\epsilon_{yy} \\tilde{\\partial}_y \\\\
\\epsilon_{xx} \\tilde{\\partial}_x \\end{bmatrix} \\epsilon_{zz}^{-1}
\\begin{bmatrix} -\\hat{\\partial}_y & \\hat{\\partial}_x \\end{bmatrix} +
\\begin{bmatrix} \\hat{\\partial}_x \\\\
\\hat{\\partial}_y \\end{bmatrix} \\mu_{zz}^{-1}
\\begin{bmatrix} \\tilde{\\partial}_x \\mu_{xx} & \\tilde{\\partial}_y \\mu_{yy} \\end{bmatrix}
\omega^2 \begin{bmatrix} \epsilon_{yy} \mu_{xx} & 0 \\
0 & \epsilon_{xx} \mu_{yy} \end{bmatrix} +
\begin{bmatrix} -\epsilon_{yy} \tilde{\partial}_y \\
\epsilon_{xx} \tilde{\partial}_x \end{bmatrix} \epsilon_{zz}^{-1}
\begin{bmatrix} -\hat{\partial}_y & \hat{\partial}_x \end{bmatrix} +
\begin{bmatrix} \hat{\partial}_x \\
\hat{\partial}_y \end{bmatrix} \mu_{zz}^{-1}
\begin{bmatrix} \tilde{\partial}_x \mu_{xx} & \tilde{\partial}_y \mu_{yy} \end{bmatrix}
$$
$\\tilde{\\partial}_x$ and $\\hat{\\partial}_x$ are the forward and backward derivatives along x,
and each $\\epsilon_{xx}$, $\\mu_{yy}$, etc. is a diagonal matrix containing the vectorized material
$\tilde{\partial}_x$ and $\hat{\partial}_x$ are the forward and backward derivatives along x,
and each $\epsilon_{xx}$, $\mu_{yy}$, etc. is a diagonal matrix containing the vectorized material
property distribution.
This operator can be used to form an eigenvalue problem of the form
@ -320,10 +322,11 @@ def operator_h(
mu_xy = sparse.diags(numpy.hstack((mu_parts[0], mu_parts[1])))
mu_z_inv = sparse.diags(1 / mu_parts[2])
op = omega * omega * eps_yx @ mu_xy + \
eps_yx @ sparse.vstack((-Dfy, Dfx)) @ eps_z_inv @ sparse.hstack((-Dby, Dbx)) + \
sparse.vstack((Dbx, Dby)) @ mu_z_inv @ sparse.hstack((Dfx, Dfy)) @ mu_xy
op = (
omega * omega * eps_yx @ mu_xy
+ eps_yx @ sparse.vstack((-Dfy, Dfx)) @ eps_z_inv @ sparse.hstack((-Dby, Dbx))
+ sparse.vstack((Dbx, Dby)) @ mu_z_inv @ sparse.hstack((Dfx, Dfy)) @ mu_xy
)
return op
@ -419,7 +422,7 @@ def _normalized_fields(
Sz_a = E[0] * numpy.conj(H[1] * phase) * dxes_real[0][1] * dxes_real[1][0]
Sz_b = E[1] * numpy.conj(H[0] * phase) * dxes_real[0][0] * dxes_real[1][1]
Sz_tavg = numpy.real(Sz_a.sum() - Sz_b.sum()) * 0.5 # 0.5 since E, H are assumed to be peak (not RMS) amplitudes
assert Sz_tavg > 0, 'Found a mode propagating in the wrong direction! Sz_tavg={}'.format(Sz_tavg)
assert Sz_tavg > 0, f'Found a mode propagating in the wrong direction! {Sz_tavg=}'
energy = epsilon * e.conj() * e
@ -717,6 +720,109 @@ def e_err(
return float(norm(op) / norm(e))
def sensitivity(
e_norm: vcfdfield_t,
h_norm: vcfdfield_t,
wavenumber: complex,
omega: complex,
dxes: dx_lists_t,
epsilon: vfdfield_t,
mu: vfdfield_t | None = None,
) -> vcfdfield_t:
r"""
Given a waveguide structure (`dxes`, `epsilon`, `mu`) and mode fields
(`e_norm`, `h_norm`, `wavenumber`, `omega`), calculates the sensitivity of the wavenumber
$\beta$ to changes in the dielectric structure $\epsilon$.
The output is a vector of the same size as `vec(epsilon)`, with each element specifying the
sensitivity of `wavenumber` to changes in the corresponding element in `vec(epsilon)`, i.e.
$$sens_{i} = \frac{\partial\beta}{\partial\epsilon_i}$$
An adjoint approach is used to calculate the sensitivity; the derivation is provided here:
Starting with the eigenvalue equation
$$\beta^2 E_{xy} = A_E E_{xy}$$
where $A_E$ is the waveguide operator from `operator_e()`, and $E_{xy} = \begin{bmatrix} E_x \\
E_y \end{bmatrix}$,
we can differentiate with respect to one of the $\epsilon$ elements (i.e. at one Yee grid point), $\epsilon_i$:
$$
(2 \beta) \partial_{\epsilon_i}(\beta) E_{xy} + \beta^2 \partial_{\epsilon_i} E_{xy}
= \partial_{\epsilon_i}(A_E) E_{xy} + A_E \partial_{\epsilon_i} E_{xy}
$$
We then multiply by $H_{yx}^\star = \begin{bmatrix}H_y^\star \\ -H_x^\star \end{bmatrix}$ from the left:
$$
(2 \beta) \partial_{\epsilon_i}(\beta) H_{yx}^\star E_{xy} + \beta^2 H_{yx}^\star \partial_{\epsilon_i} E_{xy}
= H_{yx}^\star \partial_{\epsilon_i}(A_E) E_{xy} + H_{yx}^\star A_E \partial_{\epsilon_i} E_{xy}
$$
However, $H_{yx}^\star$ is actually a left-eigenvector of $A_E$. This can be verified by inspecting
the form of `operator_h` ($A_H$) and comparing its conjugate transpose to `operator_e` ($A_E$). Also, note
$H_{yx}^\star \cdot E_{xy} = H^\star \times E$ recalls the mode orthogonality relation. See doi:10.5194/ars-9-85-201
for a similar approach. Therefore,
$$
H_{yx}^\star A_E \partial_{\epsilon_i} E_{xy} = \beta^2 H_{yx}^\star \partial_{\epsilon_i} E_{xy}
$$
and we can simplify to
$$
\partial_{\epsilon_i}(\beta)
= \frac{1}{2 \beta} \frac{H_{yx}^\star \partial_{\epsilon_i}(A_E) E_{xy} }{H_{yx}^\star E_{xy}}
$$
This expression can be quickly calculated for all $i$ by writing out the various terms of
$\partial_{\epsilon_i} A_E$ and recognizing that the vector-matrix-vector products (i.e. scalars)
$sens_i = \vec{v}_{left} \partial_{\epsilon_i} (\epsilon_{xyz}) \vec{v}_{right}$, indexed by $i$, can be expressed as
elementwise multiplications $\vec{sens} = \vec{v}_{left} \star \vec{v}_{right}$
Args:
e_norm: Normalized, vectorized E_xyz field for the mode. E.g. as returned by `normalized_fields_e`.
h_norm: Normalized, vectorized H_xyz field for the mode. E.g. as returned by `normalized_fields_e`.
wavenumber: Propagation constant for the mode. The z-axis is assumed to be continuous (i.e. without numerical dispersion).
omega: The angular frequency of the system.
dxes: Grid parameters `[dx_e, dx_h]` as described in `meanas.fdmath.types` (2D)
epsilon: Vectorized dielectric constant grid
mu: Vectorized magnetic permeability grid (default 1 everywhere)
Returns:
Sparse matrix representation of the operator.
"""
if mu is None:
mu = numpy.ones_like(epsilon)
Dfx, Dfy = deriv_forward(dxes[0])
Dbx, Dby = deriv_back(dxes[1])
eps_x, eps_y, eps_z = numpy.split(epsilon, 3)
eps_xy = sparse.diags(numpy.hstack((eps_x, eps_y)))
eps_z_inv = sparse.diags(1 / eps_z)
mu_x, mu_y, _mu_z = numpy.split(mu, 3)
mu_yx = sparse.diags(numpy.hstack((mu_y, mu_x)))
da_exxhyy = vec(dxes[1][0][:, None] * dxes[0][1][None, :])
da_eyyhxx = vec(dxes[1][1][None, :] * dxes[0][0][:, None])
ev_xy = numpy.concatenate(numpy.split(e_norm, 3)[:2]) * numpy.concatenate([da_exxhyy, da_eyyhxx])
hx, hy, hz = numpy.split(h_norm, 3)
hv_yx_conj = numpy.conj(numpy.concatenate([hy, -hx]))
sens_xy1 = (hv_yx_conj @ (omega * omega * mu_yx)) * ev_xy
sens_xy2 = (hv_yx_conj @ sparse.vstack((Dfx, Dfy)) @ eps_z_inv @ sparse.hstack((Dbx, Dby))) * ev_xy
sens_z = (hv_yx_conj @ sparse.vstack((Dfx, Dfy)) @ (-eps_z_inv * eps_z_inv)) * (sparse.hstack((Dbx, Dby)) @ eps_xy @ ev_xy)
norm = hv_yx_conj @ ev_xy
sens_tot = numpy.concatenate([sens_xy1 + sens_xy2, sens_z]) / (2 * wavenumber * norm)
return sens_tot
def solve_modes(
mode_numbers: list[int],
omega: complex,

View File

@ -4,9 +4,11 @@ Tools for working with waveguide modes in 3D domains.
This module relies heavily on `waveguide_2d` and mostly just transforms
its parameters into 2D equivalents and expands the results back into 3D.
"""
from typing import Sequence, Any
from typing import Any
from collections.abc import Sequence
import numpy
from numpy.typing import NDArray
from numpy import complexfloating
from ..fdmath import vec, unvec, dx_lists_t, fdfield_t, cfdfield_t
from . import operators, waveguide_2d
@ -21,7 +23,7 @@ def solve_mode(
slices: Sequence[slice],
epsilon: fdfield_t,
mu: fdfield_t | None = None,
) -> dict[str, complex | NDArray[numpy.float_]]:
) -> dict[str, complex | NDArray[complexfloating]]:
"""
Given a 3D grid, selects a slice from the grid and attempts to
solve for an eigenmode propagating through that slice.
@ -40,8 +42,8 @@ def solve_mode(
Returns:
```
{
'E': list[NDArray[numpy.float_]],
'H': list[NDArray[numpy.float_]],
'E': NDArray[complexfloating],
'H': NDArray[complexfloating],
'wavenumber': complex,
}
```

View File

@ -9,9 +9,9 @@ As the z-dependence is known, all the functions in this file assume a 2D grid
# TODO update module docs
import numpy
import scipy.sparse as sparse # type: ignore
from scipy import sparse
from ..fdmath import vec, unvec, dx_lists_t, fdfield_t, vfdfield_t, cfdfield_t
from ..fdmath import vec, unvec, dx_lists_t, vfdfield_t, cfdfield_t
from ..fdmath.operators import deriv_forward, deriv_back
from ..eigensolvers import signed_eigensolve, rayleigh_quotient_iteration
@ -25,6 +25,9 @@ def cylindrical_operator(
"""
Cylindrical coordinate waveguide operator of the form
(NOTE: See 10.1364/OL.33.001848)
TODO: consider 10.1364/OE.20.021583
TODO
for use with a field vector of the form `[E_r, E_y]`.
@ -73,8 +76,10 @@ def cylindrical_operator(
omega2 = omega * omega
op = (omega2 * diag((Tx, Ty)) + pa) @ diag((a0, a1)) + \
op = (
(omega2 * diag((Tx, Ty)) + pa) @ diag((a0, a1))
- (sparse.bmat(((None, Ty), (Tx, None))) + pb / omega2) @ diag((b0, b1))
)
return op

View File

@ -1,4 +1,4 @@
"""
r"""
Basic discrete calculus for finite difference (fd) simulations.
@ -43,11 +43,11 @@ Scalar derivatives and cell shifts
----------------------------------
Define the discrete forward derivative as
$$ [\\tilde{\\partial}_x f]_{m + \\frac{1}{2}} = \\frac{1}{\\Delta_{x, m}} (f_{m + 1} - f_m) $$
$$ [\tilde{\partial}_x f]_{m + \frac{1}{2}} = \frac{1}{\Delta_{x, m}} (f_{m + 1} - f_m) $$
where $f$ is a function defined at discrete locations on the x-axis (labeled using $m$).
The value at $m$ occupies a length $\\Delta_{x, m}$ along the x-axis. Note that $m$
The value at $m$ occupies a length $\Delta_{x, m}$ along the x-axis. Note that $m$
is an index along the x-axis, _not_ necessarily an x-coordinate, since each length
$\\Delta_{x, m}, \\Delta_{x, m+1}, ...$ is independently chosen.
$\Delta_{x, m}, \Delta_{x, m+1}, ...$ is independently chosen.
If we treat `f` as a 1D array of values, with the `i`-th value `f[i]` taking up a length `dx[i]`
along the x-axis, the forward derivative is
@ -56,13 +56,13 @@ along the x-axis, the forward derivative is
Likewise, discrete reverse derivative is
$$ [\\hat{\\partial}_x f ]_{m - \\frac{1}{2}} = \\frac{1}{\\Delta_{x, m}} (f_{m} - f_{m - 1}) $$
$$ [\hat{\partial}_x f ]_{m - \frac{1}{2}} = \frac{1}{\Delta_{x, m}} (f_{m} - f_{m - 1}) $$
or
deriv_back(f)[i] = (f[i] - f[i - 1]) / dx[i]
The derivatives' values are shifted by a half-cell relative to the original function, and
will have different cell widths if all the `dx[i]` ( $\\Delta_{x, m}$ ) are not
will have different cell widths if all the `dx[i]` ( $\Delta_{x, m}$ ) are not
identical:
[figure: derivatives and cell sizes]
@ -88,19 +88,19 @@ identical:
In the above figure,
`f0 =` $f_0$, `f1 =` $f_1$
`Df0 =` $[\\tilde{\\partial}f]_{0 + \\frac{1}{2}}$
`Df1 =` $[\\tilde{\\partial}f]_{1 + \\frac{1}{2}}$
`df0 =` $[\\hat{\\partial}f]_{0 - \\frac{1}{2}}$
`Df0 =` $[\tilde{\partial}f]_{0 + \frac{1}{2}}$
`Df1 =` $[\tilde{\partial}f]_{1 + \frac{1}{2}}$
`df0 =` $[\hat{\partial}f]_{0 - \frac{1}{2}}$
etc.
The fractional subscript $m + \\frac{1}{2}$ is used to indicate values defined
The fractional subscript $m + \frac{1}{2}$ is used to indicate values defined
at shifted locations relative to the original $m$, with corresponding lengths
$$ \\Delta_{x, m + \\frac{1}{2}} = \\frac{1}{2} * (\\Delta_{x, m} + \\Delta_{x, m + 1}) $$
$$ \Delta_{x, m + \frac{1}{2}} = \frac{1}{2} * (\Delta_{x, m} + \Delta_{x, m + 1}) $$
Just as $m$ is not itself an x-coordinate, neither is $m + \\frac{1}{2}$;
Just as $m$ is not itself an x-coordinate, neither is $m + \frac{1}{2}$;
carefully note the positions of the various cells in the above figure vs their labels.
If the positions labeled with $m$ are considered the "base" or "original" grid,
the positions labeled with $m + \\frac{1}{2}$ are said to lie on a "dual" or
the positions labeled with $m + \frac{1}{2}$ are said to lie on a "dual" or
"derived" grid.
For the remainder of the `Discrete calculus` section, all figures will show
@ -113,12 +113,12 @@ Gradients and fore-vectors
--------------------------
Expanding to three dimensions, we can define two gradients
$$ [\\tilde{\\nabla} f]_{m,n,p} = \\vec{x} [\\tilde{\\partial}_x f]_{m + \\frac{1}{2},n,p} +
\\vec{y} [\\tilde{\\partial}_y f]_{m,n + \\frac{1}{2},p} +
\\vec{z} [\\tilde{\\partial}_z f]_{m,n,p + \\frac{1}{2}} $$
$$ [\\hat{\\nabla} f]_{m,n,p} = \\vec{x} [\\hat{\\partial}_x f]_{m + \\frac{1}{2},n,p} +
\\vec{y} [\\hat{\\partial}_y f]_{m,n + \\frac{1}{2},p} +
\\vec{z} [\\hat{\\partial}_z f]_{m,n,p + \\frac{1}{2}} $$
$$ [\tilde{\nabla} f]_{m,n,p} = \vec{x} [\tilde{\partial}_x f]_{m + \frac{1}{2},n,p} +
\vec{y} [\tilde{\partial}_y f]_{m,n + \frac{1}{2},p} +
\vec{z} [\tilde{\partial}_z f]_{m,n,p + \frac{1}{2}} $$
$$ [\hat{\nabla} f]_{m,n,p} = \vec{x} [\hat{\partial}_x f]_{m + \frac{1}{2},n,p} +
\vec{y} [\hat{\partial}_y f]_{m,n + \frac{1}{2},p} +
\vec{z} [\hat{\partial}_z f]_{m,n,p + \frac{1}{2}} $$
or
@ -144,12 +144,12 @@ y in y, and z in z.
We call the resulting object a "fore-vector" or "back-vector", depending
on the direction of the shift. We write it as
$$ \\tilde{g}_{m,n,p} = \\vec{x} g^x_{m + \\frac{1}{2},n,p} +
\\vec{y} g^y_{m,n + \\frac{1}{2},p} +
\\vec{z} g^z_{m,n,p + \\frac{1}{2}} $$
$$ \\hat{g}_{m,n,p} = \\vec{x} g^x_{m - \\frac{1}{2},n,p} +
\\vec{y} g^y_{m,n - \\frac{1}{2},p} +
\\vec{z} g^z_{m,n,p - \\frac{1}{2}} $$
$$ \tilde{g}_{m,n,p} = \vec{x} g^x_{m + \frac{1}{2},n,p} +
\vec{y} g^y_{m,n + \frac{1}{2},p} +
\vec{z} g^z_{m,n,p + \frac{1}{2}} $$
$$ \hat{g}_{m,n,p} = \vec{x} g^x_{m - \frac{1}{2},n,p} +
\vec{y} g^y_{m,n - \frac{1}{2},p} +
\vec{z} g^z_{m,n,p - \frac{1}{2}} $$
[figure: gradient / fore-vector]
@ -172,15 +172,15 @@ Divergences
There are also two divergences,
$$ d_{n,m,p} = [\\tilde{\\nabla} \\cdot \\hat{g}]_{n,m,p}
= [\\tilde{\\partial}_x g^x]_{m,n,p} +
[\\tilde{\\partial}_y g^y]_{m,n,p} +
[\\tilde{\\partial}_z g^z]_{m,n,p} $$
$$ d_{n,m,p} = [\tilde{\nabla} \cdot \hat{g}]_{n,m,p}
= [\tilde{\partial}_x g^x]_{m,n,p} +
[\tilde{\partial}_y g^y]_{m,n,p} +
[\tilde{\partial}_z g^z]_{m,n,p} $$
$$ d_{n,m,p} = [\\hat{\\nabla} \\cdot \\tilde{g}]_{n,m,p}
= [\\hat{\\partial}_x g^x]_{m,n,p} +
[\\hat{\\partial}_y g^y]_{m,n,p} +
[\\hat{\\partial}_z g^z]_{m,n,p} $$
$$ d_{n,m,p} = [\hat{\nabla} \cdot \tilde{g}]_{n,m,p}
= [\hat{\partial}_x g^x]_{m,n,p} +
[\hat{\partial}_y g^y]_{m,n,p} +
[\hat{\partial}_z g^z]_{m,n,p} $$
or
@ -203,7 +203,7 @@ where `g = [gx, gy, gz]` is a fore- or back-vector field.
Since we applied the forward divergence to the back-vector (and vice-versa), the resulting scalar value
is defined at the back-vector's (fore-vector's) location $(m,n,p)$ and not at the locations of its components
$(m \\pm \\frac{1}{2},n,p)$ etc.
$(m \pm \frac{1}{2},n,p)$ etc.
[figure: divergence]
^^
@ -227,23 +227,23 @@ Curls
The two curls are then
$$ \\begin{aligned}
\\hat{h}_{m + \\frac{1}{2}, n + \\frac{1}{2}, p + \\frac{1}{2}} &= \\\\
[\\tilde{\\nabla} \\times \\tilde{g}]_{m + \\frac{1}{2}, n + \\frac{1}{2}, p + \\frac{1}{2}} &=
\\vec{x} (\\tilde{\\partial}_y g^z_{m,n,p + \\frac{1}{2}} - \\tilde{\\partial}_z g^y_{m,n + \\frac{1}{2},p}) \\\\
&+ \\vec{y} (\\tilde{\\partial}_z g^x_{m + \\frac{1}{2},n,p} - \\tilde{\\partial}_x g^z_{m,n,p + \\frac{1}{2}}) \\\\
&+ \\vec{z} (\\tilde{\\partial}_x g^y_{m,n + \\frac{1}{2},p} - \\tilde{\\partial}_y g^z_{m + \\frac{1}{2},n,p})
\\end{aligned} $$
$$ \begin{aligned}
\hat{h}_{m + \frac{1}{2}, n + \frac{1}{2}, p + \frac{1}{2}} &= \\
[\tilde{\nabla} \times \tilde{g}]_{m + \frac{1}{2}, n + \frac{1}{2}, p + \frac{1}{2}} &=
\vec{x} (\tilde{\partial}_y g^z_{m,n,p + \frac{1}{2}} - \tilde{\partial}_z g^y_{m,n + \frac{1}{2},p}) \\
&+ \vec{y} (\tilde{\partial}_z g^x_{m + \frac{1}{2},n,p} - \tilde{\partial}_x g^z_{m,n,p + \frac{1}{2}}) \\
&+ \vec{z} (\tilde{\partial}_x g^y_{m,n + \frac{1}{2},p} - \tilde{\partial}_y g^z_{m + \frac{1}{2},n,p})
\end{aligned} $$
and
$$ \\tilde{h}_{m - \\frac{1}{2}, n - \\frac{1}{2}, p - \\frac{1}{2}} =
[\\hat{\\nabla} \\times \\hat{g}]_{m - \\frac{1}{2}, n - \\frac{1}{2}, p - \\frac{1}{2}} $$
$$ \tilde{h}_{m - \frac{1}{2}, n - \frac{1}{2}, p - \frac{1}{2}} =
[\hat{\nabla} \times \hat{g}]_{m - \frac{1}{2}, n - \frac{1}{2}, p - \frac{1}{2}} $$
where $\\hat{g}$ and $\\tilde{g}$ are located at $(m,n,p)$
with components at $(m \\pm \\frac{1}{2},n,p)$ etc.,
while $\\hat{h}$ and $\\tilde{h}$ are located at $(m \\pm \\frac{1}{2}, n \\pm \\frac{1}{2}, p \\pm \\frac{1}{2})$
with components at $(m, n \\pm \\frac{1}{2}, p \\pm \\frac{1}{2})$ etc.
where $\hat{g}$ and $\tilde{g}$ are located at $(m,n,p)$
with components at $(m \pm \frac{1}{2},n,p)$ etc.,
while $\hat{h}$ and $\tilde{h}$ are located at $(m \pm \frac{1}{2}, n \pm \frac{1}{2}, p \pm \frac{1}{2})$
with components at $(m, n \pm \frac{1}{2}, p \pm \frac{1}{2})$ etc.
[code: curls]
@ -287,27 +287,27 @@ Maxwell's Equations
If we discretize both space (m,n,p) and time (l), Maxwell's equations become
$$ \\begin{aligned}
\\tilde{\\nabla} \\times \\tilde{E}_{l,\\vec{r}} &= -\\tilde{\\partial}_t \\hat{B}_{l-\\frac{1}{2}, \\vec{r} + \\frac{1}{2}}
- \\hat{M}_{l, \\vec{r} + \\frac{1}{2}} \\\\
\\hat{\\nabla} \\times \\hat{H}_{l-\\frac{1}{2},\\vec{r} + \\frac{1}{2}} &= \\hat{\\partial}_t \\tilde{D}_{l, \\vec{r}}
+ \\tilde{J}_{l-\\frac{1}{2},\\vec{r}} \\\\
\\tilde{\\nabla} \\cdot \\hat{B}_{l-\\frac{1}{2}, \\vec{r} + \\frac{1}{2}} &= 0 \\\\
\\hat{\\nabla} \\cdot \\tilde{D}_{l,\\vec{r}} &= \\rho_{l,\\vec{r}}
\\end{aligned} $$
$$ \begin{aligned}
\tilde{\nabla} \times \tilde{E}_{l,\vec{r}} &= -\tilde{\partial}_t \hat{B}_{l-\frac{1}{2}, \vec{r} + \frac{1}{2}}
- \hat{M}_{l, \vec{r} + \frac{1}{2}} \\
\hat{\nabla} \times \hat{H}_{l-\frac{1}{2},\vec{r} + \frac{1}{2}} &= \hat{\partial}_t \tilde{D}_{l, \vec{r}}
+ \tilde{J}_{l-\frac{1}{2},\vec{r}} \\
\tilde{\nabla} \cdot \hat{B}_{l-\frac{1}{2}, \vec{r} + \frac{1}{2}} &= 0 \\
\hat{\nabla} \cdot \tilde{D}_{l,\vec{r}} &= \rho_{l,\vec{r}}
\end{aligned} $$
with
$$ \\begin{aligned}
\\hat{B}_{\\vec{r}} &= \\mu_{\\vec{r} + \\frac{1}{2}} \\cdot \\hat{H}_{\\vec{r} + \\frac{1}{2}} \\\\
\\tilde{D}_{\\vec{r}} &= \\epsilon_{\\vec{r}} \\cdot \\tilde{E}_{\\vec{r}}
\\end{aligned} $$
$$ \begin{aligned}
\hat{B}_{\vec{r}} &= \mu_{\vec{r} + \frac{1}{2}} \cdot \hat{H}_{\vec{r} + \frac{1}{2}} \\
\tilde{D}_{\vec{r}} &= \epsilon_{\vec{r}} \cdot \tilde{E}_{\vec{r}}
\end{aligned} $$
where the spatial subscripts are abbreviated as $\\vec{r} = (m, n, p)$ and
$\\vec{r} + \\frac{1}{2} = (m + \\frac{1}{2}, n + \\frac{1}{2}, p + \\frac{1}{2})$,
$\\tilde{E}$ and $\\hat{H}$ are the electric and magnetic fields,
$\\tilde{J}$ and $\\hat{M}$ are the electric and magnetic current distributions,
and $\\epsilon$ and $\\mu$ are the dielectric permittivity and magnetic permeability.
where the spatial subscripts are abbreviated as $\vec{r} = (m, n, p)$ and
$\vec{r} + \frac{1}{2} = (m + \frac{1}{2}, n + \frac{1}{2}, p + \frac{1}{2})$,
$\tilde{E}$ and $\hat{H}$ are the electric and magnetic fields,
$\tilde{J}$ and $\hat{M}$ are the electric and magnetic current distributions,
and $\epsilon$ and $\mu$ are the dielectric permittivity and magnetic permeability.
The above is Yee's algorithm, written in a form analogous to Maxwell's equations.
The time derivatives can be expanded to form the update equations:
@ -369,34 +369,34 @@ Each component forms its own grid, offset from the others:
The divergence equations can be derived by taking the divergence of the curl equations
and combining them with charge continuity,
$$ \\hat{\\nabla} \\cdot \\tilde{J} + \\hat{\\partial}_t \\rho = 0 $$
$$ \hat{\nabla} \cdot \tilde{J} + \hat{\partial}_t \rho = 0 $$
implying that the discrete Maxwell's equations do not produce spurious charges.
Wave equation
-------------
Taking the backward curl of the $\\tilde{\\nabla} \\times \\tilde{E}$ equation and
replacing the resulting $\\hat{\\nabla} \\times \\hat{H}$ term using its respective equation,
and setting $\\hat{M}$ to zero, we can form the discrete wave equation:
Taking the backward curl of the $\tilde{\nabla} \times \tilde{E}$ equation and
replacing the resulting $\hat{\nabla} \times \hat{H}$ term using its respective equation,
and setting $\hat{M}$ to zero, we can form the discrete wave equation:
$$
\\begin{aligned}
\\tilde{\\nabla} \\times \\tilde{E}_{l,\\vec{r}} &=
-\\tilde{\\partial}_t \\hat{B}_{l-\\frac{1}{2}, \\vec{r} + \\frac{1}{2}}
- \\hat{M}_{l-1, \\vec{r} + \\frac{1}{2}} \\\\
\\mu^{-1}_{\\vec{r} + \\frac{1}{2}} \\cdot \\tilde{\\nabla} \\times \\tilde{E}_{l,\\vec{r}} &=
-\\tilde{\\partial}_t \\hat{H}_{l-\\frac{1}{2}, \\vec{r} + \\frac{1}{2}} \\\\
\\hat{\\nabla} \\times (\\mu^{-1}_{\\vec{r} + \\frac{1}{2}} \\cdot \\tilde{\\nabla} \\times \\tilde{E}_{l,\\vec{r}}) &=
\\hat{\\nabla} \\times (-\\tilde{\\partial}_t \\hat{H}_{l-\\frac{1}{2}, \\vec{r} + \\frac{1}{2}}) \\\\
\\hat{\\nabla} \\times (\\mu^{-1}_{\\vec{r} + \\frac{1}{2}} \\cdot \\tilde{\\nabla} \\times \\tilde{E}_{l,\\vec{r}}) &=
-\\tilde{\\partial}_t \\hat{\\nabla} \\times \\hat{H}_{l-\\frac{1}{2}, \\vec{r} + \\frac{1}{2}} \\\\
\\hat{\\nabla} \\times (\\mu^{-1}_{\\vec{r} + \\frac{1}{2}} \\cdot \\tilde{\\nabla} \\times \\tilde{E}_{l,\\vec{r}}) &=
-\\tilde{\\partial}_t \\hat{\\partial}_t \\epsilon_{\\vec{r}} \\tilde{E}_{l, \\vec{r}} + \\hat{\\partial}_t \\tilde{J}_{l-\\frac{1}{2},\\vec{r}} \\\\
\\hat{\\nabla} \\times (\\mu^{-1}_{\\vec{r} + \\frac{1}{2}} \\cdot \\tilde{\\nabla} \\times \\tilde{E}_{l,\\vec{r}})
+ \\tilde{\\partial}_t \\hat{\\partial}_t \\epsilon_{\\vec{r}} \\cdot \\tilde{E}_{l, \\vec{r}}
&= \\tilde{\\partial}_t \\tilde{J}_{l - \\frac{1}{2}, \\vec{r}}
\\end{aligned}
\begin{aligned}
\tilde{\nabla} \times \tilde{E}_{l,\vec{r}} &=
-\tilde{\partial}_t \hat{B}_{l-\frac{1}{2}, \vec{r} + \frac{1}{2}}
- \hat{M}_{l-1, \vec{r} + \frac{1}{2}} \\
\mu^{-1}_{\vec{r} + \frac{1}{2}} \cdot \tilde{\nabla} \times \tilde{E}_{l,\vec{r}} &=
-\tilde{\partial}_t \hat{H}_{l-\frac{1}{2}, \vec{r} + \frac{1}{2}} \\
\hat{\nabla} \times (\mu^{-1}_{\vec{r} + \frac{1}{2}} \cdot \tilde{\nabla} \times \tilde{E}_{l,\vec{r}}) &=
\hat{\nabla} \times (-\tilde{\partial}_t \hat{H}_{l-\frac{1}{2}, \vec{r} + \frac{1}{2}}) \\
\hat{\nabla} \times (\mu^{-1}_{\vec{r} + \frac{1}{2}} \cdot \tilde{\nabla} \times \tilde{E}_{l,\vec{r}}) &=
-\tilde{\partial}_t \hat{\nabla} \times \hat{H}_{l-\frac{1}{2}, \vec{r} + \frac{1}{2}} \\
\hat{\nabla} \times (\mu^{-1}_{\vec{r} + \frac{1}{2}} \cdot \tilde{\nabla} \times \tilde{E}_{l,\vec{r}}) &=
-\tilde{\partial}_t \hat{\partial}_t \epsilon_{\vec{r}} \tilde{E}_{l, \vec{r}} + \hat{\partial}_t \tilde{J}_{l-\frac{1}{2},\vec{r}} \\
\hat{\nabla} \times (\mu^{-1}_{\vec{r} + \frac{1}{2}} \cdot \tilde{\nabla} \times \tilde{E}_{l,\vec{r}})
+ \tilde{\partial}_t \hat{\partial}_t \epsilon_{\vec{r}} \cdot \tilde{E}_{l, \vec{r}}
&= \tilde{\partial}_t \tilde{J}_{l - \frac{1}{2}, \vec{r}}
\end{aligned}
$$
@ -406,27 +406,27 @@ Frequency domain
We can substitute in a time-harmonic fields
$$
\\begin{aligned}
\\tilde{E}_{l, \\vec{r}} &= \\tilde{E}_{\\vec{r}} e^{-\\imath \\omega l \\Delta_t} \\\\
\\tilde{J}_{l, \\vec{r}} &= \\tilde{J}_{\\vec{r}} e^{-\\imath \\omega (l - \\frac{1}{2}) \\Delta_t}
\\end{aligned}
\begin{aligned}
\tilde{E}_{l, \vec{r}} &= \tilde{E}_{\vec{r}} e^{-\imath \omega l \Delta_t} \\
\tilde{J}_{l, \vec{r}} &= \tilde{J}_{\vec{r}} e^{-\imath \omega (l - \frac{1}{2}) \Delta_t}
\end{aligned}
$$
resulting in
$$
\\begin{aligned}
\\tilde{\\partial}_t &\\Rightarrow (e^{ \\imath \\omega \\Delta_t} - 1) / \\Delta_t = \\frac{-2 \\imath}{\\Delta_t} \\sin(\\omega \\Delta_t / 2) e^{-\\imath \\omega \\Delta_t / 2} = -\\imath \\Omega e^{-\\imath \\omega \\Delta_t / 2}\\\\
\\hat{\\partial}_t &\\Rightarrow (1 - e^{-\\imath \\omega \\Delta_t}) / \\Delta_t = \\frac{-2 \\imath}{\\Delta_t} \\sin(\\omega \\Delta_t / 2) e^{ \\imath \\omega \\Delta_t / 2} = -\\imath \\Omega e^{ \\imath \\omega \\Delta_t / 2}\\\\
\\Omega &= 2 \\sin(\\omega \\Delta_t / 2) / \\Delta_t
\\end{aligned}
\begin{aligned}
\tilde{\partial}_t &\Rightarrow (e^{ \imath \omega \Delta_t} - 1) / \Delta_t = \frac{-2 \imath}{\Delta_t} \sin(\omega \Delta_t / 2) e^{-\imath \omega \Delta_t / 2} = -\imath \Omega e^{-\imath \omega \Delta_t / 2}\\
\hat{\partial}_t &\Rightarrow (1 - e^{-\imath \omega \Delta_t}) / \Delta_t = \frac{-2 \imath}{\Delta_t} \sin(\omega \Delta_t / 2) e^{ \imath \omega \Delta_t / 2} = -\imath \Omega e^{ \imath \omega \Delta_t / 2}\\
\Omega &= 2 \sin(\omega \Delta_t / 2) / \Delta_t
\end{aligned}
$$
This gives the frequency-domain wave equation,
$$
\\hat{\\nabla} \\times (\\mu^{-1}_{\\vec{r} + \\frac{1}{2}} \\cdot \\tilde{\\nabla} \\times \\tilde{E}_{\\vec{r}})
-\\Omega^2 \\epsilon_{\\vec{r}} \\cdot \\tilde{E}_{\\vec{r}} = -\\imath \\Omega \\tilde{J}_{\\vec{r}} e^{\\imath \\omega \\Delta_t / 2} \\\\
\hat{\nabla} \times (\mu^{-1}_{\vec{r} + \frac{1}{2}} \cdot \tilde{\nabla} \times \tilde{E}_{\vec{r}})
-\Omega^2 \epsilon_{\vec{r}} \cdot \tilde{E}_{\vec{r}} = -\imath \Omega \tilde{J}_{\vec{r}} e^{\imath \omega \Delta_t / 2} \\
$$
@ -436,48 +436,48 @@ Plane waves and Dispersion relation
With uniform material distribution and no sources
$$
\\begin{aligned}
\\mu_{\\vec{r} + \\frac{1}{2}} &= \\mu \\\\
\\epsilon_{\\vec{r}} &= \\epsilon \\\\
\\tilde{J}_{\\vec{r}} &= 0 \\\\
\\end{aligned}
\begin{aligned}
\mu_{\vec{r} + \frac{1}{2}} &= \mu \\
\epsilon_{\vec{r}} &= \epsilon \\
\tilde{J}_{\vec{r}} &= 0 \\
\end{aligned}
$$
the frequency domain wave equation simplifies to
$$ \\hat{\\nabla} \\times \\tilde{\\nabla} \\times \\tilde{E}_{\\vec{r}} - \\Omega^2 \\epsilon \\mu \\tilde{E}_{\\vec{r}} = 0 $$
$$ \hat{\nabla} \times \tilde{\nabla} \times \tilde{E}_{\vec{r}} - \Omega^2 \epsilon \mu \tilde{E}_{\vec{r}} = 0 $$
Since $\\hat{\\nabla} \\cdot \\tilde{E}_{\\vec{r}} = 0$, we can simplify
Since $\hat{\nabla} \cdot \tilde{E}_{\vec{r}} = 0$, we can simplify
$$
\\begin{aligned}
\\hat{\\nabla} \\times \\tilde{\\nabla} \\times \\tilde{E}_{\\vec{r}}
&= \\tilde{\\nabla}(\\hat{\\nabla} \\cdot \\tilde{E}_{\\vec{r}}) - \\hat{\\nabla} \\cdot \\tilde{\\nabla} \\tilde{E}_{\\vec{r}} \\\\
&= - \\hat{\\nabla} \\cdot \\tilde{\\nabla} \\tilde{E}_{\\vec{r}} \\\\
&= - \\tilde{\\nabla}^2 \\tilde{E}_{\\vec{r}}
\\end{aligned}
\begin{aligned}
\hat{\nabla} \times \tilde{\nabla} \times \tilde{E}_{\vec{r}}
&= \tilde{\nabla}(\hat{\nabla} \cdot \tilde{E}_{\vec{r}}) - \hat{\nabla} \cdot \tilde{\nabla} \tilde{E}_{\vec{r}} \\
&= - \hat{\nabla} \cdot \tilde{\nabla} \tilde{E}_{\vec{r}} \\
&= - \tilde{\nabla}^2 \tilde{E}_{\vec{r}}
\end{aligned}
$$
and we get
$$ \\tilde{\\nabla}^2 \\tilde{E}_{\\vec{r}} + \\Omega^2 \\epsilon \\mu \\tilde{E}_{\\vec{r}} = 0 $$
$$ \tilde{\nabla}^2 \tilde{E}_{\vec{r}} + \Omega^2 \epsilon \mu \tilde{E}_{\vec{r}} = 0 $$
We can convert this to three scalar-wave equations of the form
$$ (\\tilde{\\nabla}^2 + K^2) \\phi_{\\vec{r}} = 0 $$
$$ (\tilde{\nabla}^2 + K^2) \phi_{\vec{r}} = 0 $$
with $K^2 = \\Omega^2 \\mu \\epsilon$. Now we let
with $K^2 = \Omega^2 \mu \epsilon$. Now we let
$$ \\phi_{\\vec{r}} = A e^{\\imath (k_x m \\Delta_x + k_y n \\Delta_y + k_z p \\Delta_z)} $$
$$ \phi_{\vec{r}} = A e^{\imath (k_x m \Delta_x + k_y n \Delta_y + k_z p \Delta_z)} $$
resulting in
$$
\\begin{aligned}
\\tilde{\\partial}_x &\\Rightarrow (e^{ \\imath k_x \\Delta_x} - 1) / \\Delta_t = \\frac{-2 \\imath}{\\Delta_x} \\sin(k_x \\Delta_x / 2) e^{ \\imath k_x \\Delta_x / 2} = \\imath K_x e^{ \\imath k_x \\Delta_x / 2}\\\\
\\hat{\\partial}_x &\\Rightarrow (1 - e^{-\\imath k_x \\Delta_x}) / \\Delta_t = \\frac{-2 \\imath}{\\Delta_x} \\sin(k_x \\Delta_x / 2) e^{-\\imath k_x \\Delta_x / 2} = \\imath K_x e^{-\\imath k_x \\Delta_x / 2}\\\\
K_x &= 2 \\sin(k_x \\Delta_x / 2) / \\Delta_x \\\\
\\end{aligned}
\begin{aligned}
\tilde{\partial}_x &\Rightarrow (e^{ \imath k_x \Delta_x} - 1) / \Delta_t = \frac{-2 \imath}{\Delta_x} \sin(k_x \Delta_x / 2) e^{ \imath k_x \Delta_x / 2} = \imath K_x e^{ \imath k_x \Delta_x / 2}\\
\hat{\partial}_x &\Rightarrow (1 - e^{-\imath k_x \Delta_x}) / \Delta_t = \frac{-2 \imath}{\Delta_x} \sin(k_x \Delta_x / 2) e^{-\imath k_x \Delta_x / 2} = \imath K_x e^{-\imath k_x \Delta_x / 2}\\
K_x &= 2 \sin(k_x \Delta_x / 2) / \Delta_x \\
\end{aligned}
$$
with similar expressions for the y and z dimnsions (and $K_y, K_z$).
@ -485,20 +485,20 @@ with similar expressions for the y and z dimnsions (and $K_y, K_z$).
This implies
$$
\\tilde{\\nabla}^2 = -(K_x^2 + K_y^2 + K_z^2) \\phi_{\\vec{r}} \\\\
K_x^2 + K_y^2 + K_z^2 = \\Omega^2 \\mu \\epsilon = \\Omega^2 / c^2
\tilde{\nabla}^2 = -(K_x^2 + K_y^2 + K_z^2) \phi_{\vec{r}} \\
K_x^2 + K_y^2 + K_z^2 = \Omega^2 \mu \epsilon = \Omega^2 / c^2
$$
where $c = \\sqrt{\\mu \\epsilon}$.
where $c = \sqrt{\mu \epsilon}$.
Assuming real $(k_x, k_y, k_z), \\omega$ will be real only if
Assuming real $(k_x, k_y, k_z), \omega$ will be real only if
$$ c^2 \\Delta_t^2 = \\frac{\\Delta_t^2}{\\mu \\epsilon} < 1/(\\frac{1}{\\Delta_x^2} + \\frac{1}{\\Delta_y^2} + \\frac{1}{\\Delta_z^2}) $$
$$ c^2 \Delta_t^2 = \frac{\Delta_t^2}{\mu \epsilon} < 1/(\frac{1}{\Delta_x^2} + \frac{1}{\Delta_y^2} + \frac{1}{\Delta_z^2}) $$
If $\\Delta_x = \\Delta_y = \\Delta_z$, this simplifies to $c \\Delta_t < \\Delta_x / \\sqrt{3}$.
If $\Delta_x = \Delta_y = \Delta_z$, this simplifies to $c \Delta_t < \Delta_x / \sqrt{3}$.
This last form can be interpreted as enforcing causality; the distance that light
travels in one timestep (i.e., $c \\Delta_t$) must be less than the diagonal
of the smallest cell ( $\\Delta_x / \\sqrt{3}$ when on a uniform cubic grid).
travels in one timestep (i.e., $c \Delta_t$) must be less than the diagonal
of the smallest cell ( $\Delta_x / \sqrt{3}$ when on a uniform cubic grid).
Grid description
@ -515,8 +515,8 @@ to make the illustration simpler; we need at least two cells in the x dimension
demonstrate how nonuniform `dx` affects the various components.
Place the E fore-vectors at integer indices $r = (m, n, p)$ and the H back-vectors
at fractional indices $r + \\frac{1}{2} = (m + \\frac{1}{2}, n + \\frac{1}{2},
p + \\frac{1}{2})$. Remember that these are indices and not coordinates; they can
at fractional indices $r + \frac{1}{2} = (m + \frac{1}{2}, n + \frac{1}{2},
p + \frac{1}{2})$. Remember that these are indices and not coordinates; they can
correspond to arbitrary (monotonically increasing) coordinates depending on the cell widths.
Draw lines to denote the planes on which the H components and back-vectors are defined.
@ -718,14 +718,14 @@ composed of the three diagonal tensor components:
or
$$
\\epsilon = \\begin{bmatrix} \\epsilon_{xx} & 0 & 0 \\\\
0 & \\epsilon_{yy} & 0 \\\\
0 & 0 & \\epsilon_{zz} \\end{bmatrix}
\epsilon = \begin{bmatrix} \epsilon_{xx} & 0 & 0 \\
0 & \epsilon_{yy} & 0 \\
0 & 0 & \epsilon_{zz} \end{bmatrix}
$$
$$
\\mu = \\begin{bmatrix} \\mu_{xx} & 0 & 0 \\\\
0 & \\mu_{yy} & 0 \\\\
0 & 0 & \\mu_{zz} \\end{bmatrix}
\mu = \begin{bmatrix} \mu_{xx} & 0 & 0 \\
0 & \mu_{yy} & 0 \\
0 & 0 & \mu_{zz} \end{bmatrix}
$$
where the off-diagonal terms (e.g. `epsilon_xy`) are assumed to be zero.
@ -741,8 +741,24 @@ the true values can be multiplied back in after the simulation is complete if no
normalized results are needed.
"""
from .types import fdfield_t, vfdfield_t, cfdfield_t, vcfdfield_t, dx_lists_t, dx_lists_mut
from .types import fdfield_updater_t, cfdfield_updater_t
from .vectorization import vec, unvec
from . import operators, functional, types, vectorization
from .types import (
fdfield_t as fdfield_t,
vfdfield_t as vfdfield_t,
cfdfield_t as cfdfield_t,
vcfdfield_t as vcfdfield_t,
dx_lists_t as dx_lists_t,
dx_lists_mut as dx_lists_mut,
fdfield_updater_t as fdfield_updater_t,
cfdfield_updater_t as cfdfield_updater_t,
)
from .vectorization import (
vec as vec,
unvec as unvec,
)
from . import (
operators as operators,
functional as functional,
types as types,
vectorization as vectorization,
)

View File

@ -3,16 +3,18 @@ Math functions for finite difference simulations
Basic discrete calculus etc.
"""
from typing import Sequence, Callable
from typing import TypeVar
from collections.abc import Sequence, Callable
import numpy
from numpy.typing import NDArray
from numpy import floating, complexfloating
from .types import fdfield_t, fdfield_updater_t
def deriv_forward(
dx_e: Sequence[NDArray[numpy.float_]] | None = None,
dx_e: Sequence[NDArray[floating]] | None = None,
) -> tuple[fdfield_updater_t, fdfield_updater_t, fdfield_updater_t]:
"""
Utility operators for taking discretized derivatives (backward variant).
@ -36,7 +38,7 @@ def deriv_forward(
def deriv_back(
dx_h: Sequence[NDArray[numpy.float_]] | None = None,
dx_h: Sequence[NDArray[floating]] | None = None,
) -> tuple[fdfield_updater_t, fdfield_updater_t, fdfield_updater_t]:
"""
Utility operators for taking discretized derivatives (forward variant).
@ -59,10 +61,13 @@ def deriv_back(
return derivs
TT = TypeVar('TT', bound='NDArray[floating | complexfloating]')
def curl_forward(
dx_e: Sequence[NDArray[numpy.float_]] | None = None,
) -> fdfield_updater_t:
"""
dx_e: Sequence[NDArray[floating]] | None = None,
) -> Callable[[TT], TT]:
r"""
Curl operator for use with the E field.
Args:
@ -71,11 +76,11 @@ def curl_forward(
Returns:
Function `f` for taking the discrete forward curl of a field,
`f(E)` -> curlE $= \\nabla_f \\times E$
`f(E)` -> curlE $= \nabla_f \times E$
"""
Dx, Dy, Dz = deriv_forward(dx_e)
def ce_fun(e: fdfield_t) -> fdfield_t:
def ce_fun(e: TT) -> TT:
output = numpy.empty_like(e)
output[0] = Dy(e[2])
output[1] = Dz(e[0])
@ -89,9 +94,9 @@ def curl_forward(
def curl_back(
dx_h: Sequence[NDArray[numpy.float_]] | None = None,
) -> fdfield_updater_t:
"""
dx_h: Sequence[NDArray[floating]] | None = None,
) -> Callable[[TT], TT]:
r"""
Create a function which takes the backward curl of a field.
Args:
@ -100,11 +105,11 @@ def curl_back(
Returns:
Function `f` for taking the discrete backward curl of a field,
`f(H)` -> curlH $= \\nabla_b \\times H$
`f(H)` -> curlH $= \nabla_b \times H$
"""
Dx, Dy, Dz = deriv_back(dx_h)
def ch_fun(h: fdfield_t) -> fdfield_t:
def ch_fun(h: TT) -> TT:
output = numpy.empty_like(h)
output[0] = Dy(h[2])
output[1] = Dz(h[0])
@ -118,7 +123,7 @@ def curl_back(
def curl_forward_parts(
dx_e: Sequence[NDArray[numpy.float_]] | None = None,
dx_e: Sequence[NDArray[floating]] | None = None,
) -> Callable:
Dx, Dy, Dz = deriv_forward(dx_e)
@ -131,7 +136,7 @@ def curl_forward_parts(
def curl_back_parts(
dx_h: Sequence[NDArray[numpy.float_]] | None = None,
dx_h: Sequence[NDArray[floating]] | None = None,
) -> Callable:
Dx, Dy, Dz = deriv_back(dx_h)

View File

@ -3,10 +3,11 @@ Matrix operators for finite difference simulations
Basic discrete calculus etc.
"""
from typing import Sequence
from collections.abc import Sequence
import numpy
from numpy.typing import NDArray
import scipy.sparse as sparse # type: ignore
from numpy import floating
from scipy import sparse
from .types import vfdfield_t
@ -29,12 +30,12 @@ def shift_circ(
Sparse matrix for performing the circular shift.
"""
if len(shape) not in (2, 3):
raise Exception('Invalid shape: {}'.format(shape))
raise Exception(f'Invalid shape: {shape}')
if axis not in range(len(shape)):
raise Exception('Invalid direction: {}, shape is {}'.format(axis, shape))
raise Exception(f'Invalid direction: {axis}, shape is {shape}')
shifts = [abs(shift_distance) if a == axis else 0 for a in range(3)]
shifted_diags = [(numpy.arange(n) + s) % n for n, s in zip(shape, shifts)]
shifted_diags = [(numpy.arange(n) + s) % n for n, s in zip(shape, shifts, strict=True)]
ijk = numpy.meshgrid(*shifted_diags, indexing='ij')
n = numpy.prod(shape)
@ -69,12 +70,11 @@ def shift_with_mirror(
Sparse matrix for performing the shift-with-mirror.
"""
if len(shape) not in (2, 3):
raise Exception('Invalid shape: {}'.format(shape))
raise Exception(f'Invalid shape: {shape}')
if axis not in range(len(shape)):
raise Exception('Invalid direction: {}, shape is {}'.format(axis, shape))
raise Exception(f'Invalid direction: {axis}, shape is {shape}')
if shift_distance >= shape[axis]:
raise Exception('Shift ({}) is too large for axis {} of size {}'.format(
shift_distance, axis, shape[axis]))
raise Exception(f'Shift ({shift_distance}) is too large for axis {axis} of size {shape[axis]}')
def mirrored_range(n: int, s: int) -> NDArray[numpy.int_]:
v = numpy.arange(n) + s
@ -83,7 +83,7 @@ def shift_with_mirror(
return v
shifts = [shift_distance if a == axis else 0 for a in range(3)]
shifted_diags = [mirrored_range(n, s) for n, s in zip(shape, shifts)]
shifted_diags = [mirrored_range(n, s) for n, s in zip(shape, shifts, strict=True)]
ijk = numpy.meshgrid(*shifted_diags, indexing='ij')
n = numpy.prod(shape)
@ -97,7 +97,7 @@ def shift_with_mirror(
def deriv_forward(
dx_e: Sequence[NDArray[numpy.float_]],
dx_e: Sequence[NDArray[floating]],
) -> list[sparse.spmatrix]:
"""
Utility operators for taking discretized derivatives (forward variant).
@ -124,7 +124,7 @@ def deriv_forward(
def deriv_back(
dx_h: Sequence[NDArray[numpy.float_]],
dx_h: Sequence[NDArray[floating]],
) -> list[sparse.spmatrix]:
"""
Utility operators for taking discretized derivatives (backward variant).
@ -198,7 +198,7 @@ def avg_forward(axis: int, shape: Sequence[int]) -> sparse.spmatrix:
Sparse matrix for forward average operation.
"""
if len(shape) not in (2, 3):
raise Exception('Invalid shape: {}'.format(shape))
raise Exception(f'Invalid shape: {shape}')
n = numpy.prod(shape)
return 0.5 * (sparse.eye(n) + shift_circ(axis, shape))
@ -219,7 +219,7 @@ def avg_back(axis: int, shape: Sequence[int]) -> sparse.spmatrix:
def curl_forward(
dx_e: Sequence[NDArray[numpy.float_]],
dx_e: Sequence[NDArray[floating]],
) -> sparse.spmatrix:
"""
Curl operator for use with the E field.
@ -235,7 +235,7 @@ def curl_forward(
def curl_back(
dx_h: Sequence[NDArray[numpy.float_]],
dx_h: Sequence[NDArray[floating]],
) -> sparse.spmatrix:
"""
Curl operator for use with the H field.

View File

@ -1,26 +1,26 @@
"""
Types shared across multiple submodules
"""
from typing import Sequence, Callable, MutableSequence
import numpy
from collections.abc import Sequence, Callable, MutableSequence
from numpy.typing import NDArray
from numpy import floating, complexfloating
# Field types
fdfield_t = NDArray[numpy.float_]
fdfield_t = NDArray[floating]
"""Vector field with shape (3, X, Y, Z) (e.g. `[E_x, E_y, E_z]`)"""
vfdfield_t = NDArray[numpy.float_]
vfdfield_t = NDArray[floating]
"""Linearized vector field (single vector of length 3*X*Y*Z)"""
cfdfield_t = NDArray[numpy.complex_]
cfdfield_t = NDArray[complexfloating]
"""Complex vector field with shape (3, X, Y, Z) (e.g. `[E_x, E_y, E_z]`)"""
vcfdfield_t = NDArray[numpy.complex_]
vcfdfield_t = NDArray[complexfloating]
"""Linearized complex vector field (single vector of length 3*X*Y*Z)"""
dx_lists_t = Sequence[Sequence[NDArray[numpy.float_]]]
dx_lists_t = Sequence[Sequence[NDArray[floating]]]
"""
'dxes' datastructure which contains grid cell width information in the following format:
@ -31,7 +31,7 @@ dx_lists_t = Sequence[Sequence[NDArray[numpy.float_]]]
and `dy_h[0]` is the y-width of the `y=0` cells, as used when calculating dH/dy, etc.
"""
dx_lists_mut = MutableSequence[MutableSequence[NDArray[numpy.float_]]]
dx_lists_mut = MutableSequence[MutableSequence[NDArray[floating]]]
"""Mutable version of `dx_lists_t`"""

View File

@ -4,7 +4,8 @@ and a 1D array representation of that field `[f_x0, f_x1, f_x2,... f_y0,... f_z0
Vectorized versions of the field use row-major (ie., C-style) ordering.
"""
from typing import overload, Sequence
from typing import overload
from collections.abc import Sequence
import numpy
from numpy.typing import ArrayLike

View File

@ -1,4 +1,4 @@
"""
r"""
Utilities for running finite-difference time-domain (FDTD) simulations
See the discussion of `Maxwell's Equations` in `meanas.fdmath` for basic
@ -11,9 +11,9 @@ Timestep
From the discussion of "Plane waves and the Dispersion relation" in `meanas.fdmath`,
we have
$$ c^2 \\Delta_t^2 = \\frac{\\Delta_t^2}{\\mu \\epsilon} < 1/(\\frac{1}{\\Delta_x^2} + \\frac{1}{\\Delta_y^2} + \\frac{1}{\\Delta_z^2}) $$
$$ c^2 \Delta_t^2 = \frac{\Delta_t^2}{\mu \epsilon} < 1/(\frac{1}{\Delta_x^2} + \frac{1}{\Delta_y^2} + \frac{1}{\Delta_z^2}) $$
or, if $\\Delta_x = \\Delta_y = \\Delta_z$, then $c \\Delta_t < \\frac{\\Delta_x}{\\sqrt{3}}$.
or, if $\Delta_x = \Delta_y = \Delta_z$, then $c \Delta_t < \frac{\Delta_x}{\sqrt{3}}$.
Based on this, we can set
@ -27,81 +27,81 @@ Poynting Vector and Energy Conservation
Let
$$ \\begin{aligned}
\\tilde{S}_{l, l', \\vec{r}} &=& &\\tilde{E}_{l, \\vec{r}} \\otimes \\hat{H}_{l', \\vec{r} + \\frac{1}{2}} \\\\
&=& &\\vec{x} (\\tilde{E}^y_{l,m+1,n,p} \\hat{H}^z_{l',\\vec{r} + \\frac{1}{2}} - \\tilde{E}^z_{l,m+1,n,p} \\hat{H}^y_{l', \\vec{r} + \\frac{1}{2}}) \\\\
& &+ &\\vec{y} (\\tilde{E}^z_{l,m,n+1,p} \\hat{H}^x_{l',\\vec{r} + \\frac{1}{2}} - \\tilde{E}^x_{l,m,n+1,p} \\hat{H}^z_{l', \\vec{r} + \\frac{1}{2}}) \\\\
& &+ &\\vec{z} (\\tilde{E}^x_{l,m,n,p+1} \\hat{H}^y_{l',\\vec{r} + \\frac{1}{2}} - \\tilde{E}^y_{l,m,n,p+1} \\hat{H}^z_{l', \\vec{r} + \\frac{1}{2}})
\\end{aligned}
$$ \begin{aligned}
\tilde{S}_{l, l', \vec{r}} &=& &\tilde{E}_{l, \vec{r}} \otimes \hat{H}_{l', \vec{r} + \frac{1}{2}} \\
&=& &\vec{x} (\tilde{E}^y_{l,m+1,n,p} \hat{H}^z_{l',\vec{r} + \frac{1}{2}} - \tilde{E}^z_{l,m+1,n,p} \hat{H}^y_{l', \vec{r} + \frac{1}{2}}) \\
& &+ &\vec{y} (\tilde{E}^z_{l,m,n+1,p} \hat{H}^x_{l',\vec{r} + \frac{1}{2}} - \tilde{E}^x_{l,m,n+1,p} \hat{H}^z_{l', \vec{r} + \frac{1}{2}}) \\
& &+ &\vec{z} (\tilde{E}^x_{l,m,n,p+1} \hat{H}^y_{l',\vec{r} + \frac{1}{2}} - \tilde{E}^y_{l,m,n,p+1} \hat{H}^z_{l', \vec{r} + \frac{1}{2}})
\end{aligned}
$$
where $\\vec{r} = (m, n, p)$ and $\\otimes$ is a modified cross product
in which the $\\tilde{E}$ terms are shifted as indicated.
where $\vec{r} = (m, n, p)$ and $\otimes$ is a modified cross product
in which the $\tilde{E}$ terms are shifted as indicated.
By taking the divergence and rearranging terms, we can show that
$$
\\begin{aligned}
\\hat{\\nabla} \\cdot \\tilde{S}_{l, l', \\vec{r}}
&= \\hat{\\nabla} \\cdot (\\tilde{E}_{l, \\vec{r}} \\otimes \\hat{H}_{l', \\vec{r} + \\frac{1}{2}}) \\\\
&= \\hat{H}_{l', \\vec{r} + \\frac{1}{2}} \\cdot \\tilde{\\nabla} \\times \\tilde{E}_{l, \\vec{r}} -
\\tilde{E}_{l, \\vec{r}} \\cdot \\hat{\\nabla} \\times \\hat{H}_{l', \\vec{r} + \\frac{1}{2}} \\\\
&= \\hat{H}_{l', \\vec{r} + \\frac{1}{2}} \\cdot
(-\\tilde{\\partial}_t \\mu_{\\vec{r} + \\frac{1}{2}} \\hat{H}_{l - \\frac{1}{2}, \\vec{r} + \\frac{1}{2}} -
\\hat{M}_{l, \\vec{r} + \\frac{1}{2}}) -
\\tilde{E}_{l, \\vec{r}} \\cdot (\\hat{\\partial}_t \\tilde{\\epsilon}_{\\vec{r}} \\tilde{E}_{l'+\\frac{1}{2}, \\vec{r}} +
\\tilde{J}_{l', \\vec{r}}) \\\\
&= \\hat{H}_{l'} \\cdot (-\\mu / \\Delta_t)(\\hat{H}_{l + \\frac{1}{2}} - \\hat{H}_{l - \\frac{1}{2}}) -
\\tilde{E}_l \\cdot (\\epsilon / \\Delta_t )(\\tilde{E}_{l'+\\frac{1}{2}} - \\tilde{E}_{l'-\\frac{1}{2}})
- \\hat{H}_{l'} \\cdot \\hat{M}_{l} - \\tilde{E}_l \\cdot \\tilde{J}_{l'} \\\\
\\end{aligned}
\begin{aligned}
\hat{\nabla} \cdot \tilde{S}_{l, l', \vec{r}}
&= \hat{\nabla} \cdot (\tilde{E}_{l, \vec{r}} \otimes \hat{H}_{l', \vec{r} + \frac{1}{2}}) \\
&= \hat{H}_{l', \vec{r} + \frac{1}{2}} \cdot \tilde{\nabla} \times \tilde{E}_{l, \vec{r}} -
\tilde{E}_{l, \vec{r}} \cdot \hat{\nabla} \times \hat{H}_{l', \vec{r} + \frac{1}{2}} \\
&= \hat{H}_{l', \vec{r} + \frac{1}{2}} \cdot
(-\tilde{\partial}_t \mu_{\vec{r} + \frac{1}{2}} \hat{H}_{l - \frac{1}{2}, \vec{r} + \frac{1}{2}} -
\hat{M}_{l, \vec{r} + \frac{1}{2}}) -
\tilde{E}_{l, \vec{r}} \cdot (\hat{\partial}_t \tilde{\epsilon}_{\vec{r}} \tilde{E}_{l'+\frac{1}{2}, \vec{r}} +
\tilde{J}_{l', \vec{r}}) \\
&= \hat{H}_{l'} \cdot (-\mu / \Delta_t)(\hat{H}_{l + \frac{1}{2}} - \hat{H}_{l - \frac{1}{2}}) -
\tilde{E}_l \cdot (\epsilon / \Delta_t )(\tilde{E}_{l'+\frac{1}{2}} - \tilde{E}_{l'-\frac{1}{2}})
- \hat{H}_{l'} \cdot \hat{M}_{l} - \tilde{E}_l \cdot \tilde{J}_{l'} \\
\end{aligned}
$$
where in the last line the spatial subscripts have been dropped to emphasize
the time subscripts $l, l'$, i.e.
$$
\\begin{aligned}
\\tilde{E}_l &= \\tilde{E}_{l, \\vec{r}} \\\\
\\hat{H}_l &= \\tilde{H}_{l, \\vec{r} + \\frac{1}{2}} \\\\
\\tilde{\\epsilon} &= \\tilde{\\epsilon}_{\\vec{r}} \\\\
\\end{aligned}
\begin{aligned}
\tilde{E}_l &= \tilde{E}_{l, \vec{r}} \\
\hat{H}_l &= \tilde{H}_{l, \vec{r} + \frac{1}{2}} \\
\tilde{\epsilon} &= \tilde{\epsilon}_{\vec{r}} \\
\end{aligned}
$$
etc.
For $l' = l + \\frac{1}{2}$ we get
For $l' = l + \frac{1}{2}$ we get
$$
\\begin{aligned}
\\hat{\\nabla} \\cdot \\tilde{S}_{l, l + \\frac{1}{2}}
&= \\hat{H}_{l + \\frac{1}{2}} \\cdot
(-\\mu / \\Delta_t)(\\hat{H}_{l + \\frac{1}{2}} - \\hat{H}_{l - \\frac{1}{2}}) -
\\tilde{E}_l \\cdot (\\epsilon / \\Delta_t)(\\tilde{E}_{l+1} - \\tilde{E}_l)
- \\hat{H}_{l'} \\cdot \\hat{M}_l - \\tilde{E}_l \\cdot \\tilde{J}_{l + \\frac{1}{2}} \\\\
&= (-\\mu / \\Delta_t)(\\hat{H}^2_{l + \\frac{1}{2}} - \\hat{H}_{l + \\frac{1}{2}} \\cdot \\hat{H}_{l - \\frac{1}{2}}) -
(\\epsilon / \\Delta_t)(\\tilde{E}_{l+1} \\cdot \\tilde{E}_l - \\tilde{E}^2_l)
- \\hat{H}_{l'} \\cdot \\hat{M}_l - \\tilde{E}_l \\cdot \\tilde{J}_{l + \\frac{1}{2}} \\\\
&= -(\\mu \\hat{H}^2_{l + \\frac{1}{2}}
+\\epsilon \\tilde{E}_{l+1} \\cdot \\tilde{E}_l) / \\Delta_t \\ \\
+(\\mu \\hat{H}_{l + \\frac{1}{2}} \\cdot \\hat{H}_{l - \\frac{1}{2}}
+\\epsilon \\tilde{E}^2_l) / \\Delta_t \\ \\
- \\hat{H}_{l+\\frac{1}{2}} \\cdot \\hat{M}_l \\ \\
- \\tilde{E}_l \\cdot \\tilde{J}_{l+\\frac{1}{2}} \\\\
\\end{aligned}
\begin{aligned}
\hat{\nabla} \cdot \tilde{S}_{l, l + \frac{1}{2}}
&= \hat{H}_{l + \frac{1}{2}} \cdot
(-\mu / \Delta_t)(\hat{H}_{l + \frac{1}{2}} - \hat{H}_{l - \frac{1}{2}}) -
\tilde{E}_l \cdot (\epsilon / \Delta_t)(\tilde{E}_{l+1} - \tilde{E}_l)
- \hat{H}_{l'} \cdot \hat{M}_l - \tilde{E}_l \cdot \tilde{J}_{l + \frac{1}{2}} \\
&= (-\mu / \Delta_t)(\hat{H}^2_{l + \frac{1}{2}} - \hat{H}_{l + \frac{1}{2}} \cdot \hat{H}_{l - \frac{1}{2}}) -
(\epsilon / \Delta_t)(\tilde{E}_{l+1} \cdot \tilde{E}_l - \tilde{E}^2_l)
- \hat{H}_{l'} \cdot \hat{M}_l - \tilde{E}_l \cdot \tilde{J}_{l + \frac{1}{2}} \\
&= -(\mu \hat{H}^2_{l + \frac{1}{2}}
+\epsilon \tilde{E}_{l+1} \cdot \tilde{E}_l) / \Delta_t \\
+(\mu \hat{H}_{l + \frac{1}{2}} \cdot \hat{H}_{l - \frac{1}{2}}
+\epsilon \tilde{E}^2_l) / \Delta_t \\
- \hat{H}_{l+\frac{1}{2}} \cdot \hat{M}_l \\
- \tilde{E}_l \cdot \tilde{J}_{l+\frac{1}{2}} \\
\end{aligned}
$$
and for $l' = l - \\frac{1}{2}$,
and for $l' = l - \frac{1}{2}$,
$$
\\begin{aligned}
\\hat{\\nabla} \\cdot \\tilde{S}_{l, l - \\frac{1}{2}}
&= (\\mu \\hat{H}^2_{l - \\frac{1}{2}}
+\\epsilon \\tilde{E}_{l-1} \\cdot \\tilde{E}_l) / \\Delta_t \\ \\
-(\\mu \\hat{H}_{l + \\frac{1}{2}} \\cdot \\hat{H}_{l - \\frac{1}{2}}
+\\epsilon \\tilde{E}^2_l) / \\Delta_t \\ \\
- \\hat{H}_{l-\\frac{1}{2}} \\cdot \\hat{M}_l \\ \\
- \\tilde{E}_l \\cdot \\tilde{J}_{l-\\frac{1}{2}} \\\\
\\end{aligned}
\begin{aligned}
\hat{\nabla} \cdot \tilde{S}_{l, l - \frac{1}{2}}
&= (\mu \hat{H}^2_{l - \frac{1}{2}}
+\epsilon \tilde{E}_{l-1} \cdot \tilde{E}_l) / \Delta_t \\
-(\mu \hat{H}_{l + \frac{1}{2}} \cdot \hat{H}_{l - \frac{1}{2}}
+\epsilon \tilde{E}^2_l) / \Delta_t \\
- \hat{H}_{l-\frac{1}{2}} \cdot \hat{M}_l \\
- \tilde{E}_l \cdot \tilde{J}_{l-\frac{1}{2}} \\
\end{aligned}
$$
These two results form the discrete time-domain analogue to Poynting's theorem.
@ -109,25 +109,25 @@ They hint at the expressions for the energy, which can be calculated at the same
time-index as either the E or H field:
$$
\\begin{aligned}
U_l &= \\epsilon \\tilde{E}^2_l + \\mu \\hat{H}_{l + \\frac{1}{2}} \\cdot \\hat{H}_{l - \\frac{1}{2}} \\\\
U_{l + \\frac{1}{2}} &= \\epsilon \\tilde{E}_l \\cdot \\tilde{E}_{l + 1} + \\mu \\hat{H}^2_{l + \\frac{1}{2}} \\\\
\\end{aligned}
\begin{aligned}
U_l &= \epsilon \tilde{E}^2_l + \mu \hat{H}_{l + \frac{1}{2}} \cdot \hat{H}_{l - \frac{1}{2}} \\
U_{l + \frac{1}{2}} &= \epsilon \tilde{E}_l \cdot \tilde{E}_{l + 1} + \mu \hat{H}^2_{l + \frac{1}{2}} \\
\end{aligned}
$$
Rewriting the Poynting theorem in terms of the energy expressions,
$$
\\begin{aligned}
(U_{l+\\frac{1}{2}} - U_l) / \\Delta_t
&= -\\hat{\\nabla} \\cdot \\tilde{S}_{l, l + \\frac{1}{2}} \\ \\
- \\hat{H}_{l+\\frac{1}{2}} \\cdot \\hat{M}_l \\ \\
- \\tilde{E}_l \\cdot \\tilde{J}_{l+\\frac{1}{2}} \\\\
(U_l - U_{l-\\frac{1}{2}}) / \\Delta_t
&= -\\hat{\\nabla} \\cdot \\tilde{S}_{l, l - \\frac{1}{2}} \\ \\
- \\hat{H}_{l-\\frac{1}{2}} \\cdot \\hat{M}_l \\ \\
- \\tilde{E}_l \\cdot \\tilde{J}_{l-\\frac{1}{2}} \\\\
\\end{aligned}
\begin{aligned}
(U_{l+\frac{1}{2}} - U_l) / \Delta_t
&= -\hat{\nabla} \cdot \tilde{S}_{l, l + \frac{1}{2}} \\
- \hat{H}_{l+\frac{1}{2}} \cdot \hat{M}_l \\
- \tilde{E}_l \cdot \tilde{J}_{l+\frac{1}{2}} \\
(U_l - U_{l-\frac{1}{2}}) / \Delta_t
&= -\hat{\nabla} \cdot \tilde{S}_{l, l - \frac{1}{2}} \\
- \hat{H}_{l-\frac{1}{2}} \cdot \hat{M}_l \\
- \tilde{E}_l \cdot \tilde{J}_{l-\frac{1}{2}} \\
\end{aligned}
$$
This result is exact and should practically hold to within numerical precision. No time-
@ -147,10 +147,10 @@ of the time-domain fields.
The Ricker wavelet (normalized second derivative of a Gaussian) is commonly used for the pulse
shape. It can be written
$$ f_r(t) = (1 - \\frac{1}{2} (\\omega (t - \\tau))^2) e^{-(\\frac{\\omega (t - \\tau)}{2})^2} $$
$$ f_r(t) = (1 - \frac{1}{2} (\omega (t - \tau))^2) e^{-(\frac{\omega (t - \tau)}{2})^2} $$
with $\\tau > \\frac{2 * \\pi}{\\omega}$ as a minimum delay to avoid a discontinuity at
t=0 (assuming the source is off for t<0 this gives $\\sim 10^{-3}$ error at t=0).
with $\tau > \frac{2 * \pi}{\omega}$ as a minimum delay to avoid a discontinuity at
t=0 (assuming the source is off for t<0 this gives $\sim 10^{-3}$ error at t=0).
@ -159,8 +159,22 @@ Boundary conditions
# TODO notes about boundaries / PMLs
"""
from .base import maxwell_e, maxwell_h
from .pml import cpml_params, updates_with_cpml
from .energy import (poynting, poynting_divergence, energy_hstep, energy_estep,
delta_energy_h2e, delta_energy_j)
from .boundaries import conducting_boundary
from .base import (
maxwell_e as maxwell_e,
maxwell_h as maxwell_h,
)
from .pml import (
cpml_params as cpml_params,
updates_with_cpml as updates_with_cpml,
)
from .energy import (
poynting as poynting,
poynting_divergence as poynting_divergence,
energy_hstep as energy_hstep,
energy_estep as energy_estep,
delta_energy_h2e as delta_energy_h2e,
delta_energy_j as delta_energy_j,
)
from .boundaries import (
conducting_boundary as conducting_boundary,
)

View File

@ -15,13 +15,17 @@ def conducting_boundary(
) -> tuple[fdfield_updater_t, fdfield_updater_t]:
dirs = [0, 1, 2]
if direction not in dirs:
raise Exception('Invalid direction: {}'.format(direction))
raise Exception(f'Invalid direction: {direction}')
dirs.remove(direction)
u, v = dirs
boundary_slice: list[Any]
shifted1_slice: list[Any]
shifted2_slice: list[Any]
if polarity < 0:
boundary_slice = [slice(None)] * 3 # type: list[Any]
shifted1_slice = [slice(None)] * 3 # type: list[Any]
boundary_slice = [slice(None)] * 3
shifted1_slice = [slice(None)] * 3
boundary_slice[direction] = 0
shifted1_slice[direction] = 1
@ -42,7 +46,7 @@ def conducting_boundary(
if polarity > 0:
boundary_slice = [slice(None)] * 3
shifted1_slice = [slice(None)] * 3
shifted2_slice = [slice(None)] * 3 # type: list[Any]
shifted2_slice = [slice(None)] * 3
boundary_slice[direction] = -1
shifted1_slice[direction] = -2
shifted2_slice[direction] = -3
@ -64,4 +68,4 @@ def conducting_boundary(
return ep, hp
raise Exception('Bad polarity: {}'.format(polarity))
raise Exception(f'Bad polarity: {polarity}')

View File

@ -12,7 +12,7 @@ def poynting(
h: fdfield_t,
dxes: dx_lists_t | None = None,
) -> fdfield_t:
"""
r"""
Calculate the poynting vector `S` ($S$).
This is the energy transfer rate (amount of energy `U` per `dt` transferred
@ -44,16 +44,16 @@ def poynting(
The full relationship is
$$
\\begin{aligned}
(U_{l+\\frac{1}{2}} - U_l) / \\Delta_t
&= -\\hat{\\nabla} \\cdot \\tilde{S}_{l, l + \\frac{1}{2}} \\ \\
- \\hat{H}_{l+\\frac{1}{2}} \\cdot \\hat{M}_l \\ \\
- \\tilde{E}_l \\cdot \\tilde{J}_{l+\\frac{1}{2}} \\\\
(U_l - U_{l-\\frac{1}{2}}) / \\Delta_t
&= -\\hat{\\nabla} \\cdot \\tilde{S}_{l, l - \\frac{1}{2}} \\ \\
- \\hat{H}_{l-\\frac{1}{2}} \\cdot \\hat{M}_l \\ \\
- \\tilde{E}_l \\cdot \\tilde{J}_{l-\\frac{1}{2}} \\\\
\\end{aligned}
\begin{aligned}
(U_{l+\frac{1}{2}} - U_l) / \Delta_t
&= -\hat{\nabla} \cdot \tilde{S}_{l, l + \frac{1}{2}} \\
- \hat{H}_{l+\frac{1}{2}} \cdot \hat{M}_l \\
- \tilde{E}_l \cdot \tilde{J}_{l+\frac{1}{2}} \\
(U_l - U_{l-\frac{1}{2}}) / \Delta_t
&= -\hat{\nabla} \cdot \tilde{S}_{l, l - \frac{1}{2}} \\
- \hat{H}_{l-\frac{1}{2}} \cdot \hat{M}_l \\
- \tilde{E}_l \cdot \tilde{J}_{l-\frac{1}{2}} \\
\end{aligned}
$$
These equalities are exact and should practically hold to within numerical precision.

View File

@ -7,7 +7,8 @@ PML implementations
"""
# TODO retest pmls!
from typing import Callable, Sequence, Any
from typing import Any
from collections.abc import Callable, Sequence
from copy import deepcopy
import numpy
from numpy.typing import NDArray, DTypeLike
@ -33,10 +34,10 @@ def cpml_params(
) -> dict[str, Any]:
if axis not in range(3):
raise Exception('Invalid axis: {}'.format(axis))
raise Exception(f'Invalid axis: {axis}')
if polarity not in (-1, 1):
raise Exception('Invalid polarity: {}'.format(polarity))
raise Exception(f'Invalid polarity: {polarity}')
if thickness <= 2:
raise Exception('It would be wise to have a pml with 4+ cells of thickness')
@ -111,7 +112,7 @@ def updates_with_cpml(
params_H: list[list[tuple[Any, Any, Any, Any]]] = deepcopy(params_E)
for axis in range(3):
for pp, polarity in enumerate((-1, 1)):
for pp, _polarity in enumerate((-1, 1)):
cpml_param = cpml_params[axis][pp]
if cpml_param is None:
psi_E[axis][pp] = (None, None)
@ -184,7 +185,7 @@ def updates_with_cpml(
def update_H(
e: fdfield_t,
h: fdfield_t,
mu: fdfield_t = numpy.ones(3),
mu: fdfield_t | tuple[int, int, int] = (1, 1, 1),
) -> None:
dyEx = Dfy(e[0])
dzEx = Dfz(e[0])

View File

@ -3,7 +3,8 @@
Test fixtures
"""
from typing import Iterable, Any
# ruff: noqa: ARG001
from typing import Any
import numpy
from numpy.typing import NDArray
import pytest # type: ignore
@ -20,18 +21,18 @@ FixtureRequest = Any
(5, 5, 5),
# (7, 7, 7),
])
def shape(request: FixtureRequest) -> Iterable[tuple[int, ...]]:
yield (3, *request.param)
def shape(request: FixtureRequest) -> tuple[int, ...]:
return (3, *request.param)
@pytest.fixture(scope='module', params=[1.0, 1.5])
def epsilon_bg(request: FixtureRequest) -> Iterable[float]:
yield request.param
def epsilon_bg(request: FixtureRequest) -> float:
return request.param
@pytest.fixture(scope='module', params=[1.0, 2.5])
def epsilon_fg(request: FixtureRequest) -> Iterable[float]:
yield request.param
def epsilon_fg(request: FixtureRequest) -> float:
return request.param
@pytest.fixture(scope='module', params=['center', '000', 'random'])
@ -40,7 +41,7 @@ def epsilon(
shape: tuple[int, ...],
epsilon_bg: float,
epsilon_fg: float,
) -> Iterable[NDArray[numpy.float64]]:
) -> NDArray[numpy.float64]:
is3d = (numpy.array(shape) == 1).sum() == 0
if is3d:
if request.param == '000':
@ -60,17 +61,17 @@ def epsilon(
high=max(epsilon_bg, epsilon_fg),
size=shape)
yield epsilon
return epsilon
@pytest.fixture(scope='module', params=[1.0]) # 1.5
def j_mag(request: FixtureRequest) -> Iterable[float]:
yield request.param
def j_mag(request: FixtureRequest) -> float:
return request.param
@pytest.fixture(scope='module', params=[1.0, 1.5])
def dx(request: FixtureRequest) -> Iterable[float]:
yield request.param
def dx(request: FixtureRequest) -> float:
return request.param
@pytest.fixture(scope='module', params=['uniform', 'centerbig'])
@ -78,7 +79,7 @@ def dxes(
request: FixtureRequest,
shape: tuple[int, ...],
dx: float,
) -> Iterable[list[list[NDArray[numpy.float64]]]]:
) -> list[list[NDArray[numpy.float64]]]:
if request.param == 'uniform':
dxes = [[numpy.full(s, dx) for s in shape[1:]] for _ in range(2)]
elif request.param == 'centerbig':
@ -90,5 +91,5 @@ def dxes(
dxe = [PRNG.uniform(low=1.0 * dx, high=1.1 * dx, size=s) for s in shape[1:]]
dxh = [(d + numpy.roll(d, -1)) / 2 for d in dxe]
dxes = [dxe, dxh]
yield dxes
return dxes

View File

@ -1,4 +1,4 @@
from typing import Iterable
# ruff: noqa: ARG001
import dataclasses
import pytest # type: ignore
import numpy
@ -61,24 +61,24 @@ def test_poynting_planes(sim: 'FDResult') -> None:
# Also see conftest.py
@pytest.fixture(params=[1 / 1500])
def omega(request: FixtureRequest) -> Iterable[float]:
yield request.param
def omega(request: FixtureRequest) -> float:
return request.param
@pytest.fixture(params=[None])
def pec(request: FixtureRequest) -> Iterable[NDArray[numpy.float64] | None]:
yield request.param
def pec(request: FixtureRequest) -> NDArray[numpy.float64] | None:
return request.param
@pytest.fixture(params=[None])
def pmc(request: FixtureRequest) -> Iterable[NDArray[numpy.float64] | None]:
yield request.param
def pmc(request: FixtureRequest) -> NDArray[numpy.float64] | None:
return request.param
#@pytest.fixture(scope='module',
# params=[(25, 5, 5)])
#def shape(request):
# yield (3, *request.param)
#def shape(request: FixtureRequest):
# return (3, *request.param)
@pytest.fixture(params=['diag']) # 'center'
@ -86,7 +86,7 @@ def j_distribution(
request: FixtureRequest,
shape: tuple[int, ...],
j_mag: float,
) -> Iterable[NDArray[numpy.float64]]:
) -> NDArray[numpy.float64]:
j = numpy.zeros(shape, dtype=complex)
center_mask = numpy.zeros(shape, dtype=bool)
center_mask[:, shape[1] // 2, shape[2] // 2, shape[3] // 2] = True
@ -96,7 +96,7 @@ def j_distribution(
elif request.param == 'diag':
j[numpy.roll(center_mask, [1, 1, 1], axis=(1, 2, 3))] = (1 + 1j) * j_mag
j[numpy.roll(center_mask, [-1, -1, -1], axis=(1, 2, 3))] = (1 - 1j) * j_mag
yield j
return j
@dataclasses.dataclass()
@ -145,7 +145,7 @@ def sim(
omega=omega,
dxes=dxes,
epsilon=eps_vec,
matrix_solver_opts={'atol': 1e-15, 'tol': 1e-11},
matrix_solver_opts={'atol': 1e-15, 'rtol': 1e-11},
)
e = unvec(e_vec, shape[1:])

View File

@ -1,4 +1,4 @@
from typing import Iterable
# ruff: noqa: ARG001
import pytest # type: ignore
import numpy
from numpy.typing import NDArray
@ -44,30 +44,30 @@ def test_pml(sim: FDResult, src_polarity: int) -> None:
# Also see conftest.py
@pytest.fixture(params=[1 / 1500])
def omega(request: FixtureRequest) -> Iterable[float]:
yield request.param
def omega(request: FixtureRequest) -> float:
return request.param
@pytest.fixture(params=[None])
def pec(request: FixtureRequest) -> Iterable[NDArray[numpy.float64] | None]:
yield request.param
def pec(request: FixtureRequest) -> NDArray[numpy.float64] | None:
return request.param
@pytest.fixture(params=[None])
def pmc(request: FixtureRequest) -> Iterable[NDArray[numpy.float64] | None]:
yield request.param
def pmc(request: FixtureRequest) -> NDArray[numpy.float64] | None:
return request.param
@pytest.fixture(params=[(30, 1, 1),
(1, 30, 1),
(1, 1, 30)])
def shape(request: FixtureRequest) -> Iterable[tuple[int, ...]]:
yield (3, *request.param)
def shape(request: FixtureRequest) -> tuple[int, int, int]:
return (3, *request.param)
@pytest.fixture(params=[+1, -1])
def src_polarity(request: FixtureRequest) -> Iterable[int]:
yield request.param
def src_polarity(request: FixtureRequest) -> int:
return request.param
@pytest.fixture()
@ -78,7 +78,7 @@ def j_distribution(
dxes: dx_lists_mut,
omega: float,
src_polarity: int,
) -> Iterable[NDArray[numpy.complex128]]:
) -> NDArray[numpy.complex128]:
j = numpy.zeros(shape, dtype=complex)
dim = numpy.where(numpy.array(shape[1:]) > 1)[0][0] # Propagation axis
@ -106,7 +106,7 @@ def j_distribution(
j = fdfd.waveguide_3d.compute_source(E=e, wavenumber=wavenumber_corrected, omega=omega, dxes=dxes,
axis=dim, polarity=src_polarity, slices=slices, epsilon=epsilon)
yield j
return j
@pytest.fixture()
@ -115,9 +115,9 @@ def epsilon(
shape: tuple[int, ...],
epsilon_bg: float,
epsilon_fg: float,
) -> Iterable[NDArray[numpy.float64]]:
) -> NDArray[numpy.float64]:
epsilon = numpy.full(shape, epsilon_fg, dtype=float)
yield epsilon
return epsilon
@pytest.fixture(params=['uniform'])
@ -127,7 +127,7 @@ def dxes(
dx: float,
omega: float,
epsilon_fg: float,
) -> Iterable[list[list[NDArray[numpy.float64]]]]:
) -> list[list[NDArray[numpy.float64]]]:
if request.param == 'uniform':
dxes = [[numpy.full(s, dx) for s in shape[1:]] for _ in range(2)]
dim = numpy.where(numpy.array(shape[1:]) > 1)[0][0] # Propagation axis
@ -141,7 +141,7 @@ def dxes(
epsilon_effective=epsilon_fg,
thickness=10,
)
yield dxes
return dxes
@pytest.fixture()
@ -162,7 +162,7 @@ def sim(
omega=omega,
dxes=dxes,
epsilon=eps_vec,
matrix_solver_opts={'atol': 1e-15, 'tol': 1e-11},
matrix_solver_opts={'atol': 1e-15, 'rtol': 1e-11},
)
e = unvec(e_vec, shape[1:])

View File

@ -1,4 +1,5 @@
from typing import Iterable, Any
# ruff: noqa: ARG001
from typing import Any
import dataclasses
import pytest # type: ignore
import numpy
@ -101,7 +102,7 @@ def test_poynting_divergence(sim: 'TDResult') -> None:
def test_poynting_planes(sim: 'TDResult') -> None:
mask = (sim.js[0] != 0).any(axis=0)
if mask.sum() > 1:
pytest.skip('test_poynting_planes can only test single point sources, got {}'.format(mask.sum()))
pytest.skip(f'test_poynting_planes can only test single point sources, got {mask.sum()}')
args: dict[str, Any] = {
'dxes': sim.dxes,
@ -150,8 +151,8 @@ def test_poynting_planes(sim: 'TDResult') -> None:
@pytest.fixture(params=[0.3])
def dt(request: FixtureRequest) -> Iterable[float]:
yield request.param
def dt(request: FixtureRequest) -> float:
return request.param
@dataclasses.dataclass()
@ -168,8 +169,8 @@ class TDResult:
@pytest.fixture(params=[(0, 4, 8)]) # (0,)
def j_steps(request: FixtureRequest) -> Iterable[tuple[int, ...]]:
yield request.param
def j_steps(request: FixtureRequest) -> tuple[int, ...]:
return request.param
@pytest.fixture(params=['center', 'random'])
@ -177,7 +178,7 @@ def j_distribution(
request: FixtureRequest,
shape: tuple[int, ...],
j_mag: float,
) -> Iterable[NDArray[numpy.float64]]:
) -> NDArray[numpy.float64]:
j = numpy.zeros(shape)
if request.param == 'center':
j[:, shape[1] // 2, shape[2] // 2, shape[3] // 2] = j_mag
@ -185,7 +186,7 @@ def j_distribution(
j[:, 0, 0, 0] = j_mag
elif request.param == 'random':
j[:] = PRNG.uniform(low=-j_mag, high=j_mag, size=shape)
yield j
return j
@pytest.fixture()
@ -199,8 +200,7 @@ def sim(
j_steps: tuple[int, ...],
) -> TDResult:
is3d = (numpy.array(shape) == 1).sum() == 0
if is3d:
if dt != 0.3:
if is3d and dt != 0.3:
pytest.skip('Skipping dt != 0.3 because test is 3D (for speed)')
sim = TDResult(

View File

@ -1,5 +1,3 @@
from typing import Any
import numpy
from numpy.typing import NDArray
@ -10,22 +8,25 @@ PRNG = numpy.random.RandomState(12345)
def assert_fields_close(
x: NDArray,
y: NDArray,
*args: Any,
**kwargs: Any,
) -> None:
numpy.testing.assert_allclose(
x, y, verbose=False, # type: ignore
err_msg='Fields did not match:\n{}\n{}'.format(numpy.moveaxis(x, -1, 0),
numpy.moveaxis(y, -1, 0)),
*args,
**kwargs,
) -> None:
x_disp = numpy.moveaxis(x, -1, 0)
y_disp = numpy.moveaxis(y, -1, 0)
numpy.testing.assert_allclose(
x, # type: ignore
y, # type: ignore
*args,
verbose=False,
err_msg=f'Fields did not match:\n{x_disp}\n{y_disp}',
**kwargs,
)
def assert_close(
x: NDArray,
y: NDArray,
*args: Any,
**kwargs: Any,
*args,
**kwargs,
) -> None:
numpy.testing.assert_allclose(x, y, *args, **kwargs)

View File

@ -1,391 +0,0 @@
import scipy
import numpy
from numpy.typing import ArrayLike, NDArray
#from simphony.elements import Model
#from simphony.netlist import Subcircuit
#from simphony.simulation import SweepSimulation
#
#from matplotlib import pyplot as plt
#
#
#class PeriodicLayer(Model):
# def __init__(self, left_modes, right_modes, s_params):
# self.left_modes = left_modes
# self.right_modes = right_modes
# self.left_ports = len(self.left_modes)
# self.right_ports = len(self.right_modes)
# self.normalize_fields()
# self.s_params = s_params
#
# def normalize_fields(self):
# for mode in range(len(self.left_modes)):
# self.left_modes[mode].normalize()
# for mode in range(len(self.right_modes)):
# self.right_modes[mode].normalize()
#
#
#class PeriodicEME:
# def __init__(self, layers=[], num_periods=1):
# self.layers = layers
# self.num_periods = num_periods
# self.wavelength = wavelength
#
# def propagate(self):
# wl = self.wavelength
# if not len(self.layers):
# raise Exception("Must place layers before propagating")
#
# num_modes = max([l.num_modes for l in self.layers])
# iface = InterfaceSingleMode if num_modes == 1 else InterfaceMultiMode
#
# eme = EME(layers=self.layers)
# left, right = eme.propagate()
# self.single_period = eme.s_matrix
#
# period_layer = PeriodicLayer(left.modes, right.modes, self.single_period)
# current_layer = PeriodicLayer(left.modes, right.modes, self.single_period)
# interface = iface(right, left)
#
# for _ in range(self.num_periods - 1):
# current_layer.s_params = cascade(current_layer, interface, wl)
# current_layer.s_params = cascade(current_layer, period_layer, wl)
#
# self.s_params = current_layer.s_params
#
#
#class EME:
# def __init__(self, layers=[]):
# self.layers = layers
# self.wavelength = None
#
# def propagate(self):
# layers = self.layers
# wl = layers[0].wavelength if self.wavelength is None else self.wavelength
# if not len(layers):
# raise Exception("Must place layers before propagating")
#
# num_modes = max([l.num_modes for l in layers])
# iface = InterfaceSingleMode if num_modes == 1 else InterfaceMultiMode
#
# first_layer = layers[0]
# current = Current(wl, first_layer)
# interface = iface(first_layer, layers[1])
#
# current.s = cascade(current, interface, wl)
# current.right_pins = interface.right_pins
#
# for index in range(1, len(layers) - 1):
# layer1 = layers[index]
# layer2 = layers[index + 1]
# interface = iface(layer1, layer2)
#
# current.s = cascade(current, layer1, wl)
# current.right_pins = layer1.right_pins
#
# current.s = cascade(current, interface, wl)
# current.right_pins = interface.right_pins
#
# last_layer = layers[-1]
# current.s = cascade(current, last_layer, wl)
# current.right_pins = last_layer.right_pins
#
# self.s_matrix = current.s
# return first_layer, last_layer
#
#
#def stack(sa, sb):
# qab = numpy.eye() - sa.r11 @ sb.r11
# qba = numpy.eye() - sa.r11 @ sb.r11
# #s.t12 = sa.t12 @ numpy.pinv(qab) @ sb.t12
# #s.r21 = sa.t12 @ numpy.pinv(qab) @ sb.r22 @ sa.t21 + sa.r22
# #s.r12 = sb.t21 @ numpy.pinv(qba) @ sa.r11 @ sb.t12 + sb.r11
# #s.t21 = sb.t21 @ numpy.pinv(qba) @ sa.t21
# s.t12 = sa.t12 @ numpy.linalg.solve(qab, sb.t12)
# s.r21 = sa.t12 @ numpy.linalg.solve(qab, sb.r22 @ sa.t21) + sa.r22
# s.r12 = sb.t21 @ numpy.linalg.solve(qba, sa.r11 @ sb.t12) + sb.r11
# s.t21 = sb.t21 @ numpy.linalg.solve(qba, sa.t21)
# return s
#
#
#def cascade(first, second, wavelength):
# circuit = Subcircuit("Device")
#
# circuit.add([(first, "first"), (second, "second")])
# for port in range(first.right_ports):
# circuit.connect("first", "right" + str(port), "second", "left" + str(port))
#
# simulation = SweepSimulation(circuit, wavelength, wavelength, num=1)
# result = simulation.simulate()
# return result.s
#
#
#class InterfaceSingleMode(Model):
# def __init__(self, layer1, layer2, num_modes=1):
# self.num_modes = num_modes
# self.num_ports = 2 * num_modes
# self.s = self.solve(layer1, layer2, num_modes)
#
# def solve(self, layer1, layer2, num_modes):
# nm = num_modes
# s = numpy.zeros((2 * nm, 2 * nm), dtype=complex)
#
# for ii, left_mode in enumerate(layer1.modes):
# for oo, right_mode in enumerate(layer2.modes):
# r, t = get_rt(left_mode, right_mode)
# s[ oo, ii] = r
# s[nm + oo, ii] = t
#
# for ii, right_mode in enumerate(layer2.modes):
# for oo, left_mode in enumerate(layer1.modes):
# r, t = get_rt(right_mode, left_mode)
# s[ oo, nm + ii] = t
# s[nm + oo, nm + ii] = r
# return s
#
#
#class InterfaceMultiMode(Model):
# def __init__(self, layer1, layer2):
# self.s = self.solve(layer1, layer2)
#
# def solve(self, layer1, layer2):
# n1p = layer1.num_modes
# n2p = layer2.num_modes
# num_ports = n1p + n2p
# s = numpy.zeros((num_ports, num_ports), dtype=complex)
#
# for l1p in range(n1p):
# ts = get_t(l1p, layer1, layer2)
# rs = get_r(l1p, layer1, layer2, ts)
# s[n1p:, l1p] = ts
# s[:n1p, l1p] = rs
#
# for l2p in range(n2p):
# ts = get_t(l2p, layer2, layer1)
# rs = get_r(l2p, layer2, layer1, ts)
# s[:n1p, n1p + l2p] = ts
# s[n1p:, n1p + l2p] = rs
#
# return s
def get_t(p, left, right):
A = numpy.empty(left.num_modes, right.num_modes, dtype=complex)
for i in range(left.num_modes):
for k in range(right.num_modes):
# TODO optimize loop
A[i, k] = inner_product(right[k], left[i]) + inner_product(left[i], right[k])
b = numpy.zeros(left.num_modes)
b[p] = 2 * inner_product(left[p], left[p])
x = numpy.linalg.solve(A, b)
# NOTE: `A` does not depend on `p`, so it might make sense to partially precompute
# the solution (pinv(A), or LU decomposition?)
# Actually solve() can take multiple vectors, so just pass it something with the full diagonal?
xx = numpy.matmul(numpy.linalg.pinv(A), b) #TODO verify
assert numpy.allclose(xx, x)
return x
def get_r(p, left, right, t):
r = numpy.empty(left.num_modes, dtype=complex)
for ii in range(left.num_modes):
r[ii] = sum((inner_product(right[kk], left[ii]) - inner_product(left[ii], right[kk])) * t[kk]
for kk in range(right.num_modes)
) / (2 * inner_product(left[ii], left[ii]))
return r
def get_rt(left, right):
a = 0.5 * (inner_product(left, right) + inner_product(right, left))
b = 0.5 * (inner_product(left, right) - inner_product(right, left))
t = (a ** 2 - b ** 2) / a
r = 1 - t / (a + b)
return -r, t
def inner_product(left_E, right_H, dxes):
# ExHy' - EyHx'
cross_z = left_E[0] * right_H[1].conj() - left_E[1] * right_H[0].conj()
# cross_z = numpy.cross(left_E, numpy.conj(right_H), axisa=0, axisb=0, axisc=0)[2]
return numpy.trapz(numpy.trapz(cross_z, dxes[0][0]), dxes[0][1]) / 2 # TODO might need cumsum on dxes
def propagation_matrix(mode_neffs: ArrayLike, wavelength: float, distance: float):
eigenv = numpy.array(mode_neffs, copy=False) * 2 * numpy.pi / wavelength
prop_diag = numpy.diag(numpy.exp(distance * 1j * numpy.hstack((eigenv, eigenv))))
prop_matrix = numpy.roll(prop_diag, len(eigenv), axis=0)
return prop_matrix
def connect_s(
A: NDArray[numpy.complex128],
k: int,
B: NDArray[numpy.complex128],
l: int,
) -> NDArray[numpy.complex128]:
"""
TODO
freq x ... x n x n
Based on skrf implementation
Connect two n-port networks' s-matrices together.
Specifically, connect port `k` on network `A` to port `l` on network
`B`. The resultant network has nports = (A.rank + B.rank-2); first
(A.rank - 1) ports are from `A`, remainder are from B.
Assumes same reference impedance for both `k` and `l`; may need to
connect an "impedance mismatch" thru element first!
Args:
A: S-parameter matrix of `A`, shape is fxnxn
k: port index on `A` (port indices start from 0)
B: S-parameter matrix of `B`, shape is fxnxn
l: port index on `B`
Returns:
new S-parameter matrix
"""
if k > A.shape[-1] - 1 or l > B.shape[-1] - 1:
raise ValueError("port indices are out of range")
#C = scipy.sparse.block_diag((A, B), dtype=complex)
#return innerconnect_s(C, k, A.shape[0] + l)
nA = A.shape[-1]
nB = B.shape[-1]
nC = nA + nB - 2
assert numpy.array_equal(A.shape[:-2], B.shape[:-2])
ll = slice(l, l + 1)
kk = slice(k, k + 1)
denom = 1 - A[..., kk, kk] * B[..., ll, ll]
Anew = A + A[..., kk, :] * B[..., ll, ll] * A[..., :, kk] / denom
Bnew = A[..., kk, :] * B[..., :, ll] / denom
Anew = numpy.delete(Anew, (k,), 1)
Anew = numpy.delete(Anew, (k,), 2)
Bnew = numpy.delete(Bnew, (l,), 1)
Bnew = numpy.delete(Bnew, (l,), 2)
dtype = (A[0, 0] * B[0, 0]).dtype
C = numpy.zeros(tuple(A.shape[:-2]) + (nC, nC), dtype=dtype)
C[..., :nA - 1, :nA - 1] = Anew
C[..., nA - 1:, nA - 1:] = Bnew
return C
def innerconnect_s(
S: NDArray[numpy.complex128],
k: int,
l: int,
) -> NDArray[numpy.complex128]:
"""
TODO
freq x ... x n x n
Based on skrf implementation
Connect two ports of a single n-port network's s-matrix.
Specifically, connect port `k` to port `l` on `S`. This results in
a (n-2)-port network.
Assumes same reference impedance for both `k` and `l`; may need to
connect an "impedance mismatch" thru element first!
Args:
S: S-parameter matrix of `S`, shape is fxnxn
k: port index on `S` (port indices start from 0)
l: port index on `S`
Returns:
new S-parameter matrix
Notes:
- Compton, R.C., "Perspectives in microwave circuit analysis",
doi:10.1109/MWSCAS.1989.101955
- Filipsson, G., "A New General Computer Algorithm for S-Matrix Calculation
of Interconnected Multiports",
doi:10.1109/EUMA.1981.332972
"""
if k > S.shape[-1] - 1 or l > S.shape[-1] - 1:
raise ValueError("port indices are out of range")
ll = slice(l, l + 1)
kk = slice(k, k + 1)
mkl = 1 - S[..., kk, ll]
mlk = 1 - S[..., ll, kk]
C = S + (
S[..., kk, :] * S[..., :, l] * mlk
+ S[..., ll, :] * S[..., :, k] * mkl
+ S[..., kk, :] * S[..., l, l] * S[..., :, kk]
+ S[..., ll, :] * S[..., k, k] * S[..., :, ll]
) / (
mlk * mkl - S[..., kk, kk] * S[..., ll, ll]
)
# remove connected ports
C = numpy.delete(C, (k, l), 1)
C = numpy.delete(C, (k, l), 2)
return C
def s2abcd(
S: NDArray[numpy.complex128],
z0: NDArray[numpy.complex128],
) -> NDArray[numpy.complex128]:
assert numpy.array_equal(S.shape[:2] == (2, 2))
Z1, Z2 = z0
cross = S[0, 1] * S[1, 0]
T = numpy.empty_like(S, dtype=complex)
T[0, 0, :] = (Z1.conj() + S[0, 0] * Z1) * (1 - S[1, 1]) + cross * Z1 # A numerator
T[0, 1, :] = (Z1.conj() + S[0, 0] * Z1) * (Z1.conj() + S[1, 1] * Z2) - cross * Z1 * Z2 # B numerator
T[1, 0, :] = (1 - S[0, 0]) * (1 - S[1, 1]) - cross # C numerator
T[1, 1, :] = (1 - S[0, 0]) * (Z2.conj() + S[1, 1] * Z2) + cross * Z2 # D numerator
det = 2 * S[1, 0] * numpy.sqrt(Z1.real * Z2.real)
T /= det
return T
def generalize_S(
S: NDArray[numpy.complex128],
r0: float,
z0: NDArray[numpy.complex128],
) -> NDArray[numpy.complex128]:
g = (z0 - r0) / (z0 + r0)
D = numpy.diag((1 - g) / numpy.abs(1 - g.conj()) * numpy.sqrt(1 - numpy.abs(g * g.conj())))
G = numpy.diag(g)
U = numpy.eye(S.shape[-1]).reshape((S.ndim - 2) * (1,) + (S.shape[-2], S.shape[-1]))
S_gen = pinv(D.conj()) @ (S - G.conj()) @ pinv(U - G @ S) @ D
return S_gen
def change_R0(
S: NDArray[numpy.complex128],
r1: float,
r2: float,
) -> NDArray[numpy.complex128]:
g = (r2 - r1) / (r2 + r1)
U = numpy.eye(S.shape[-1]).reshape((S.ndim - 2) * (1,) + (S.shape[-2], S.shape[-1]))
G = U * g
S_r2 = (S - G) @ pinv(U - G @ S)
return S_r2
# Zc = numpy.sqrt(B / C)
# gamma = numpy.arccosh(A) / L_TL
# n_eff = -1j * gamma * c_light / (2 * pi * f)
# n_eff_grp = n_eff + f * diff(n_eff) / diff(f)
# attenuation = (1 - S[0, 0] * S[0, 0].conj()) / (S[1, 0] * S[1, 0].conj())
# R = numpy.real(gamma * Zc)
# C = numpy.real(gamma / Zc)
# L = numpy.imag(gamma * Zc) / (-1j * 2 * pi * f)
# G = numpy.imag(gamma / Zc) / (-1j * 2 * pi * f)

View File

@ -321,7 +321,6 @@ class _ToMarkdown:
"""Wrap URLs in Python-Markdown-compatible <angle brackets>."""
return re.sub(r'(?<![<"\'])(\s*)((?:http|ftp)s?://[^>)\s]+)(\s*)', r'\1<\2>\3', text)
import subprocess
class _MathPattern(InlineProcessor):
NAME = 'pdoc-math'

View File

@ -39,8 +39,8 @@ include = [
]
dynamic = ["version"]
dependencies = [
"numpy~=1.21",
"scipy",
"numpy>=1.26",
"scipy~=1.14",
]
@ -51,3 +51,48 @@ path = "meanas/__init__.py"
dev = ["pytest", "pdoc", "gridlock"]
examples = ["gridlock"]
test = ["pytest"]
[tool.ruff]
exclude = [
".git",
"dist",
]
line-length = 245
indent-width = 4
lint.dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
lint.select = [
"NPY", "E", "F", "W", "B", "ANN", "UP", "SLOT", "SIM", "LOG",
"C4", "ISC", "PIE", "PT", "RET", "TCH", "PTH", "INT",
"ARG", "PL", "R", "TRY",
"G010", "G101", "G201", "G202",
"Q002", "Q003", "Q004",
]
lint.ignore = [
#"ANN001", # No annotation
"ANN002", # *args
"ANN003", # **kwargs
"ANN401", # Any
"ANN101", # self: Self
"SIM108", # single-line if / else assignment
"RET504", # x=y+z; return x
"PIE790", # unnecessary pass
"ISC003", # non-implicit string concatenation
"C408", # dict(x=y) instead of {'x': y}
"PLR09", # Too many xxx
"PLR2004", # magic number
"PLC0414", # import x as x
"TRY003", # Long exception message
"TRY002", # Exception()
]
[[tool.mypy.overrides]]
module = [
"scipy",
"scipy.optimize",
"scipy.linalg",
"scipy.sparse",
"scipy.sparse.linalg",
]
ignore_missing_imports = true

387
spar.py
View File

@ -1,387 +0,0 @@
# Based on scripts from Andy H. va rfcafe
# IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES. VOL 42, NO 2. FEBRUARY 1994
# Conversions Between S, Z, Y, h, ABCD, and T Parameters which are Valid for Complex Source and Load Impedances
# Dean A. Frickey, Member, EEE
# Tables I and II
import numpy
def s_to_z(s, z0):
"""
Scattering (S) to Impedance (Z)
Args:
s: The scattering matrix.
z0: The port impedances (Ohms).
Returns:
The impedance matrix.
"""
z0c = numpy.conj(z0)
z = numpy.empty([2, 2], dtype=complex)
z[0, 0] = (z0c[0] + s[0, 0] * z0[0]) * (1 - s[1, 1]) + s[0, 1] * s[1, 0] * z0[0]
z[0, 1] = 2 * s[0, 1] * numpy.sqrt(z0[0].real * z0[1].real)
z[1, 0] = 2 * s[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
z[1, 1] = (1 - s[0, 0]) * (z0c[1] + s[1, 1] * z0[1]) + s[0, 1] * s[1, 0] * z0[1]
z /= (1 - s[0, 0]) * (1 - s[1, 1]) - s[0, 1] * s[1, 0]
return z
def z_to_s(z, z0):
"""
Impedance (Z) to Scattering (S)
Args:
z: The impedance matrix.
z0: The port impedances (Ohms).
Returns:
The scattering matrix.
"""
z0c = numpy.conj(z0)
s = numpy.empty([2, 2], dtype=complex)
s[0, 0] = (z[0, 0] - z0c[0]) * (z[1, 1] + z0[1]) - z[0, 1] * z[1, 0]
s[0, 1] = 2 * z[0, 1] * numpy.sqrt(z0[0].real * z0[1].real)
s[1, 0] = 2 * z[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
s[1, 1] = (z[0, 0] + z0[0]) * (z[1, 1] - z0c[1]) - z[0, 1] * z[1, 0]
s /= (z[0, 0] + z0[0]) * (z[1, 1] + z0[1]) - z[0, 1] * z[1, 0]
return s
def s_to_y(s, z0):
"""
Scattering (S) to Admittance (Y)
Args:
s: The scattering matrix.
z0: The port impedances (Ohms).
Returns:
The admittance matrix.
"""
z0c = numpy.conj(z0)
y = numpy.empty([2, 2], dtype=complex)
y[0, 0] = (1 - s[0, 0]) * (z0c[1] + s[1, 1] * z0[1]) + s[0,1] * s[1, 0] * z0[1]
y[0, 1] = -2 * s[0,1] * numpy.sqrt(z0[0].real * z0[1].real)
y[1, 0] = -2 * s[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
y[1, 1] = (z0c[0] + s[0, 0] * z0[0]) * (1 - s[1,1]) + s[0,1] * s[1, 0] * z0[0]
y /= (z0c[0] + s[0, 0] * z0[0]) * (z0c[1] + s[1, 1] * z0[1]) - s[0,1] * s[1, 0] * z0[0] * z0[1]
return y
def y_to_s(y, z0):
"""
Admittance (Y) to Scattering (S)
Args:
y: The admittance matrix.
z0: The port impedances (Ohms).
Returns:
The scattering matrix.
"""
z0c = numpy.conj(z0)
s = numpy.empty([2, 2], dtype=complex)
s[0, 0] = (1 - y[0, 0] * z0c[0]) * (1 + y[1, 1] * z0[1]) + y[0,1] * y[1, 0] * z0c[0] * z0[1]
s[0, 1] = -2 * y[0,1] * numpy.sqrt(z0[0].real * z0[1].real)
s[1, 0] = -2 * y[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
s[1, 1] = (1 + y[0, 0] * z0[0]) * (1 - y[1,1] * z0c[1]) + y[0,1] * y[1, 0] * z0[0] * z0c[1]
s /= (1 + y[0, 0] * z0[0]) * (1 + y[1, 1] * z0[1]) - y[0,1] * y[1, 0] * z0[0] * z0[1]
return s
def s_to_h(s, z0):
"""
Scattering (S) to Hybrid (H)
Args:
s: The scattering matrix.
z0: The port impedances (Ohms).
Returns:
The hybrid matrix.
"""
z0c = numpy.conj(z0)
h = numpy.empty([2, 2], dtype=complex)
h[0, 0] = (z0c[0] + s[0, 0] * z0[0]) * (z0c[1] + s[1, 1] * z0[1]) - s[0,1] * s[1, 0] * z0[0] * z0[1]
h[0, 1] = 2 * s[0,1] * numpy.sqrt(z0[0].real * z0[1].real)
h[1, 0] = -2 * s[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
h[1, 1] = (1 - s[0, 0]) * (1 - s[1,1]) - s[0,1] * s[1, 0]
h /= (1 - s[0, 0]) * (z0c[1] + s[1, 1] * z0[1]) + s[0,1] * s[1, 0] * z0[1]
return h
def h_to_s(h, z0):
"""
Hybrid (H) to Scattering (S)
Args:
h: The hybrid matrix.
z0: The port impedances (Ohms).
Returns:
The scattering matrix.
"""
z0c = numpy.conj(z0)
s = numpy.empty([2, 2], dtype=complex)
s[0, 0] = (h[0, 0] - z0c[0]) * (1 + h[1, 1] * z0[1]) - h[0,1] * h[1, 0] * z0[1]
s[0, 1] = 2 * h[0,1] * numpy.sqrt(z0[0].real * z0[1].real)
s[1, 0] = -2 * h[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
s[1, 1] = (z0[0] + h[0, 0]) * (1 - h[1,1] * z0c[1]) + h[0,1] * h[1, 0] * z0c[1]
s /= (z0[0] + h[0, 0]) * (1 + h[1, 1] * z0[1]) - h[0,1] * h[1, 0] * z0[1]
return s
def s_to_abcd(s, z0):
"""
Scattering to Chain (ABCD)
Args:
s: The scattering matrix.
z0: The port impedances (Ohms).
Returns:
The chain matrix.
"""
z0c = numpy.conj(z0)
ans = numpy.empty([2, 2], dtype=complex)
ans[0, 0] = (z0c[0] + s[0, 0] * z0[0]) * (1 - s[1, 1]) + s[0,1] * s[1, 0] * z0[0]
ans[0, 1] = (z0c[0] + s[0, 0] * z0[0]) * (z0c[1] + s[1,1] * z0[1]) - s[0,1] * s[1, 0] * z0[0] * z0[1]
ans[1, 0] = (1 - s[0, 0]) * (1 - s[1, 1]) - s[0,1] * s[1, 0]
ans[1, 1] = (1 - s[0, 0]) * (z0c[1] + s[1,1] * z0[1]) + s[0,1] * s[1, 0] * z0[1]
ans /= 2 * s[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
return ans
def abcd_to_s(abcd, z0):
"""
Chain (ABCD) to Scattering (S)
Args:
abcd: The chain matrix.
z0: The port impedances (Ohms).
Return:
The scattering matrix.
"""
A = abcd[0, 0]
B = abcd[0, 1]
C = abcd[1, 0]
D = abcd[1, 1]
z0c = numpy.conj(z0)
s = numpy.empty([2, 2], dtype=complex)
s[0, 0] = A * z0[1] + B - C * z0c[0] * z0[1] - D * z0c[0]
s[0, 1] = 2 * (A * D - B * C) * numpy.sqrt(z0[0].real * z0[1].real)
s[1, 0] = 2 * numpy.sqrt(z0[0].real * z0[1].real)
s[1, 1] = -A * z0c[1] + B - C * z0[0] * z0c[1] + D * z0[0]
s /= A * z0[1] + B + C * z0[0] * z0[1] + D * z0[0]
return s
def t_to_z(t, z0):
"""
Chain Transfer (T) to Impedance (Z)
Args:
t: The chain transfer matrix.
z0: The port impedances (Ohms).
Returns:
The impedance matrix.
"""
z0c = numpy.conj(z0)
z = numpy.empty([2, 2], dtype=complex)
z[0, 0] = z0c[0] * (t[0, 0] + t[0, 1]) + z0[0] * (t[1, 0] + t[1,1])
z[0, 1] = 2 * numpy.sqrt(z0[0].real * z0[1].real) * (t[0, 0] * t[1,1] - t[0,1] * t[1, 0])
z[1, 0] = 2 * numpy.sqrt(z0[0].real * z0[1].real)
z[1, 1] = z0c[1] * (t[0, 0] - t[1, 0]) - z0[1] * (t[0,1] - t[1,1])
z /= t[0, 0] + t[0, 1] - t[1, 0] - t[1,1]
return z
def z_to_t(z, z0):
"""
Impedance (Z) to Chain Transfer (T)
Args:
z: The impedance matrix.
z0: The port impedances (Ohms).
Returns:
The chain transfer matrix.
"""
z0c = numpy.conj(z0)
t = numpy.empty([2, 2], dtype=complex)
t[0, 0] = (z[0, 0] + z0[0]) * (z[1, 1] + z0[1]) - z[0,1] * z[1, 0]
t[0, 1] = (z[0, 0] + z0[0]) * (z0c[1] - z[1,1]) + z[0,1] * z[1, 0]
t[1, 0] = (z[0, 0] - z0c[0]) * (z[1, 1] + z0[1]) - z[0,1] * z[1, 0]
t[1, 1] = (z0c[0] - z[0, 0]) * (z[1,1] - z0c[1]) + z[0,1] * z[1, 0]
t /= 2 * z[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
return t
def t_to_y(t, z0):
"""
Chain Transfer (T) to Admittance (Y)
Args:
t: The chain transfer matrix.
z0: The port impedances (Ohms).
Returns:
The admittance matrix.
"""
z0c = numpy.conj(z0)
y = numpy.empty([2, 2], dtype=complex)
y[0, 0] = z0c[1] * (t[0, 0] - t[1, 0]) - z0[1] * (t[0, 1] - t[1,1])
y[0, 1] = -2 * numpy.sqrt(z0[0].real * z0[1].real) * (t[0, 0] * t[1,1] - t[0,1] * t[1, 0])
y[1, 0] = -2 * numpy.sqrt(z0[0].real * z0[1].real)
y[1, 1] = z0c[0] * (t[0, 0] + t[0,1]) + z0[0] * (t[1, 0] + t[1,1])
y /= t[0, 0] * z0c[0] * z0c[1] - t[0, 1] * z0c[0] * z0[1] + t[1, 0] * z0[0] * z0c[1] - t[1,1] * z0[0] * z0[1]
return y
def y_to_t(y, z0):
"""
Admittance (Y) to Chain Transfer (T)
Args:
y: The admittance matrix.
z0: The port impedances (Ohms).
Returns:
The chain transfer matrix.
"""
z0c = numpy.conj(z0)
t = numpy.empty([2, 2], dtype=complex)
t[0, 0] = (-1 - y[0, 0] * z0[0]) * (1 + y[1, 1] * z0[1]) + y[0,1] * y[1, 0] * z0[0] * z0[1]
t[0, 1] = (1 + y[0, 0] * z0[0]) * (1 - y[1,1] * z0c[1]) + y[0,1] * y[1, 0] * z0[0] * z0c[1]
t[1, 0] = (y[0, 0] * z0c[0] - 1) * (1 + y[1, 1] * z0[1]) - y[0,1] * y[1, 0] * z0c[0] * z0[1]
t[1, 1] = (1 - y[0, 0] * z0c[0]) * (1 - y[1,1] * z0c[1]) - y[0,1] * y[1, 0] * z0c[0] * z0c[1]
t /= 2 * y[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
return t
def t_to_h(t, z0):
"""
Chain Transfer (T) to Hybrid (H)
Args:
t: The chain transfer matrix.
z0: The port impedances (Ohms).
Returns:
The hybrid matrix.
"""
z0c = numpy.conj(z0)
h = numpy.empty([2, 2], dtype=complex)
h[0, 0] = z0c[1]*(t[0, 0] * z0c[0] + t[1, 0] * z0[0]) - z0[1] * (t[0, 1] * z0c[0] + t[1,1] * z0[0])
h[0, 1] = 2 * numpy.sqrt(z0[0].real * z0[1].real) * (t[0, 0] * t[1,1] - t[0,1] * t[1, 0])
h[1, 0] = -2 * numpy.sqrt(z0[0].real * z0[1].real)
h[1, 1] = t[0, 0] + t[0,1] - t[1, 0] - t[1,1]
h /= z0c[1] * (t[0, 0] - t[1, 0]) - z0[1] * (t[0, 1] - t[1,1])
return h
def h_to_t(h, z0):
"""
Hybrid (H) to Chain Transfer (T)
Args:
t: The hybrid matrix.
z0: The port impedances (Ohms).
Returns:
The chain transfer matrix.
"""
z0c = numpy.conj(z0)
t = numpy.empty([2, 2], dtype=complex)
t[0, 0] = (-h[0, 0] - z0[0]) * (1 + h[1, 1] * z0[1]) + h[0,1] * h[1, 0] * z0[1]
t[0, 1] = (h[0, 0] + z0[0]) * (1 - h[1,1] * z0c[1]) + h[0,1] * h[1, 0] * z0c[1]
t[1, 0] = (z0c[0] - h[0, 0]) * (1 + h[1, 1] * z0[1]) + h[0,1] * h[1, 0] * z0[1]
t[1, 1] = (h[0, 0] - z0c[0]) * (1 - h[1,1] * z0c[1]) + h[0,1] * h[1, 0] * z0c[1]
t /= 2 * h[1, 0] * numpy.sqrt(z0[0].real * z0[1].real)
return t
def t_to_abcd(t, z0):
"""
Chain Transfer (T) to Chain (ABCD)
Args:
t: The chain transfer matrix.
z0: The port impedances (Ohms).
Returns:
The chain matrix.
"""
z0c = numpy.conj(z0)
ans = numpy.empty([2, 2], dtype=complex)
ans[0, 0] = z0c[0] * (t[0, 0] + t[0, 1]) + z0[0] * (t[1, 0] + t[1, 1])
ans[0, 1] = z0c[1] * (t[0, 0] * z0c[0] + t[1, 0] * z0[0]) - z0[1] * (t[0, 1] * z0c[0] + t[1, 1] * z0[0])
ans[1, 0] = t[0, 0] + t[0, 1] - t[1, 0] - t[1, 1]
ans[1, 1] = z0c[1] * (t[0, 0] - t[1, 0]) - z0[1] * (t[0, 1] - t[1, 1])
ans /= 2 * numpy.sqrt(z0[0].real * z0[1].real)
return ans
def abcd_to_t(abcd, z0):
"""
Chain (ABCD) to Chain Transfer (T)
Args:
abcd: The chain matrix.
z0: The port impedances (Ohms).
Returns:
The chain transfer matrix.
"""
# Break out the components
A = abcd[0, 0]
B = abcd[0, 1]
C = abcd[1, 0]
D = abcd[1, 1]
z0c = numpy.conj(z0)
t = numpy.empty([2, 2], dtype=complex)
t[0, 0] = A * z0[1] + B + C * z0[0] * z0[1] + D * z0[0]
t[0, 1] = A * z0c[1] - B + C * z0[0] * z0c[1] - D * z0[0]
t[1, 0] = A * z0[1] + B - C * z0c[0] * z0[1] - D * z0c[0]
t[1, 1] = A * z0c[1] - B - C * z0c[0] * z0c[1] + D * z0c[0]
t /= 2 * numpy.sqrt(z0[0].real * z0[1].real)
return t

View File

@ -1,58 +0,0 @@
# IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES. VOL 42, NO 2. FEBRUARY 1994
# Conversions Between S, Z, Y, h, ABCD, and T Parameters which are Valid for Complex Source and Load Impedances
# Dean A. Frickey, Member, EEE
# Tables I and II
import numpy as np
from two_port_conversions import *
""" Testing """
# Analog Devices - HMC455LP3 - S parameters
# High output IP3 GaAs InGaP Heterojunction Bipolar Transistor
# MHz S (Magntidue and Angle (deg))
# 1487.273 0.409 160.117 4.367 163.864 0.063 115.967 0.254 -132.654
s11 = 0.409 * np.exp(1j * np.radians(160.117))
s12 = 4.367 * np.exp(1j * np.radians(163.864))
s21 = 0.063 * np.exp(1j * np.radians(115.967))
s22 = 0.254 * np.exp(1j * np.radians(-132.654))
s_orig = np.array([[s11, s12], [s21, s22]])
# Data specified at 50 Ohms (adding small complex component to test conversions)
z1, z2 = 50 + 0.01j, 50 - 0.02j
z0 = np.array([z1, z2])
""" Conversions """
print(f'Original S: \n{s_orig}\n')
# S --> Z --> T --> Z --> S
z = s_to_z(s_orig, z0)
t = z_to_t(z, z0)
z = t_to_z(t, z0)
s = z_to_s(z, z0)
print(f'Test (S --> Z --> T --> Z --> S): \n{s}\n')
# S --> Y --> T --> Y --> S
y = s_to_y(s_orig, z0)
t = y_to_t(y, z0)
y = t_to_y(t, z0)
s = y_to_s(y, z0)
print(f'Test (S --> Y --> T --> Y --> S): \n{s}\n')
# S --> H --> T --> H --> S
h = s_to_h(s_orig, z0)
t = h_to_t(h, z0)
h = t_to_h(t, z0)
s = h_to_s(h, z0)
print(f'Test (S --> H --> T --> H --> S): \n{s}\n')
# S --> ABCD --> T --> ABCD --> S
abcd = s_to_abcd(s_orig, z0)
t = abcd_to_t(abcd, z0)
abcd = t_to_abcd(t, z0)
s = abcd_to_s(abcd, z0)
print(f'Test (S --> ABCD --> T --> ABCD --> S): \n{s}\n')

268
spconv.py
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@ -1,268 +0,0 @@
import scipy
import numpy
from numpy.typing import ArrayLike, NDArray
from numpy.linalg import pinv
from numpy import sqrt, real, abs, pi
def diag(twod):
# numpy.diag() but makes a stack of diagonal matrices
return numpy.einsum('ij,jk->ijk', twod, numpy.eye(twod.shape[-1], dtype=twod.dtype))
def s2z(s, zref):
# G0_inv @ inv(I - S) @ (S Z0 + Z0*) @ G0
# Where Z0 is diag(zref) and G0 = diag(1/sqrt(abs(real(zref))))
nf = s.shape[-1]
I = numpy.eye(nf)[None, :, :]
zref = numpy.array(zref, copy=False)
gref = 1 / sqrt(abs(zref.real))
z = diag(1 / gref) @ pinv(I - s) @ ( S @ diag(zref) + diag(zref).conj()) @ diag(gref)
return z
def change_of_zref(
s, # (nf, np, np)
zref_old, # (nf, np)
zref_new, # (nf, np)
):
# Change-of-Z0 to Z0'
# S' = inv(A) @ (S - rho*) @ inv(I - rho @ S) @ A*
# A = inv(G0') @ G0 @ inv(I - rho*) (diagonal)
# rho = (Z0' - Z0) @ inv(Z0' + Z0) (diagonal)
I = numpy.zeros_like(SL)
numpy.einsum('...jj->...j', I)[...] = 1
zref_old = numpy.array(zref_old, copy=False)
zref_new = numpy.array(zref_new, copy=False)
g_old = 1 / sqrt(abs(zref_old.real))
r_new = sqrt(abs(zref_new.real))
rhov = (zref_new - zref_old) / (zref_new + zref_old)
av = r_new * g_old / (1 - rhov.conj())
s_new = diag(1 / av) @ (s - diag(rhov.conj())) @ pinv(I[None, :] - diag(rhov) @ S) @ diag(av.conj())
return s_new
def embedding(
See, # (nf, ne, ne)
Sei, # (nf, ne, ni)
Sie, # (nf, ni, ne)
Sii, # (nf, ni, ni)
SL, # (nf, ni, ni)
):
# Reveyrand, doi:10.1109/INMMIC.2018.8430023
I = numpy.zeros_like(SL)
numpy.einsum('...jj->...j', I)[...] = 1
S_tot = See + Sei @ pinv(I - SL @ Sii) @ SL @ Sie
return S_tot
def deembedding(
Sei, # (nf, ne, ni)
Sie, # (nf, ni, ne)
Sext, # (nf, ne, ne)
See, # (nf, ne, ne)
Si, # (nf, ni, ni)
):
# Reveyrand, doi:10.1109/INMMIC.2018.8430023
# Requires balanced number of ports, similar to VNA calibration
Sei_inv = pinv(Sei)
Sdif = Sext - See
return Sei_inv @ Sdif @ pinv(Sie + Sii @ Sei_inv @ Sdif)
def thru_with_Zref_change(
zref0, # (nf,)
zref1, # (nf,)
):
s = numpy.empty(tuple(zref0.shape) + (2, 2), dtype=complex)
s[..., 0, 0] = zref1 - zref0
s[..., 0, 1] = 2 * sqrt(zref0 * zref1)
s[..., 1, 0] = s[..., 0, 1]
s[..., 1, 1] = -s[..., 0, 0]
s /= zref0 + zref1
return s
def propagation_matrix(mode_neffs: ArrayLike, wavelength: float, distance: float):
eigenv = numpy.array(mode_neffs, copy=False) * 2 * pi / wavelength
prop_diag = numpy.diag(numpy.exp(distance * 1j * numpy.hstack((eigenv, eigenv))))
prop_matrix = numpy.roll(prop_diag, len(eigenv), axis=0)
return prop_matrix
def connect_s(
A: NDArray[numpy.complex128],
k: int,
B: NDArray[numpy.complex128],
l: int,
) -> NDArray[numpy.complex128]:
"""
TODO
freq x ... x n x n
Based on skrf implementation
Connect two n-port networks' s-matrices together.
Specifically, connect port `k` on network `A` to port `l` on network
`B`. The resultant network has nports = (A.rank + B.rank-2); first
(A.rank - 1) ports are from `A`, remainder are from B.
Assumes same reference impedance for both `k` and `l`; may need to
connect an "impedance mismatch" thru element first!
Args:
A: S-parameter matrix of `A`, shape is fxnxn
k: port index on `A` (port indices start from 0)
B: S-parameter matrix of `B`, shape is fxnxn
l: port index on `B`
Returns:
new S-parameter matrix
"""
if k > A.shape[-1] - 1 or l > B.shape[-1] - 1:
raise ValueError("port indices are out of range")
#C = scipy.sparse.block_diag((A, B), dtype=complex)
#return innerconnect_s(C, k, A.shape[0] + l)
nA = A.shape[-1]
nB = B.shape[-1]
nC = nA + nB - 2
assert numpy.array_equal(A.shape[:-2], B.shape[:-2])
ll = slice(l, l + 1)
kk = slice(k, k + 1)
denom = 1 - A[..., kk, kk] * B[..., ll, ll]
Anew = A + A[..., kk, :] * B[..., ll, ll] * A[..., :, kk] / denom
Bnew = A[..., kk, :] * B[..., :, ll] / denom
Anew = numpy.delete(Anew, (k,), 1)
Anew = numpy.delete(Anew, (k,), 2)
Bnew = numpy.delete(Bnew, (l,), 1)
Bnew = numpy.delete(Bnew, (l,), 2)
dtype = (A[0, 0] * B[0, 0]).dtype
C = numpy.zeros(tuple(A.shape[:-2]) + (nC, nC), dtype=dtype)
C[..., :nA - 1, :nA - 1] = Anew
C[..., nA - 1:, nA - 1:] = Bnew
return C
def innerconnect_s(
S: NDArray[numpy.complex128],
k: int,
l: int,
) -> NDArray[numpy.complex128]:
"""
TODO
freq x ... x n x n
Based on skrf implementation
Connect two ports of a single n-port network's s-matrix.
Specifically, connect port `k` to port `l` on `S`. This results in
a (n-2)-port network.
Assumes same reference impedance for both `k` and `l`; may need to
connect an "impedance mismatch" thru element first!
Args:
S: S-parameter matrix of `S`, shape is fxnxn
k: port index on `S` (port indices start from 0)
l: port index on `S`
Returns:
new S-parameter matrix
Notes:
- Compton, R.C., "Perspectives in microwave circuit analysis",
doi:10.1109/MWSCAS.1989.101955
- Filipsson, G., "A New General Computer Algorithm for S-Matrix Calculation
of Interconnected Multiports",
doi:10.1109/EUMA.1981.332972
"""
if k > S.shape[-1] - 1 or l > S.shape[-1] - 1:
raise ValueError("port indices are out of range")
ll = slice(l, l + 1)
kk = slice(k, k + 1)
mkl = 1 - S[..., kk, ll]
mlk = 1 - S[..., ll, kk]
C = S + (
S[..., kk, :] * S[..., :, l] * mlk
+ S[..., ll, :] * S[..., :, k] * mkl
+ S[..., kk, :] * S[..., l, l] * S[..., :, kk]
+ S[..., ll, :] * S[..., k, k] * S[..., :, ll]
) / (
mlk * mkl - S[..., kk, kk] * S[..., ll, ll]
)
# remove connected ports
C = numpy.delete(C, (k, l), 1)
C = numpy.delete(C, (k, l), 2)
return C
def s2abcd(
S: NDArray[numpy.complex128],
z0: NDArray[numpy.complex128],
) -> NDArray[numpy.complex128]:
assert numpy.array_equal(S.shape[:2] == (2, 2))
Z1, Z2 = z0
cross = S[0, 1] * S[1, 0]
T = numpy.empty_like(S, dtype=complex)
T[0, 0, :] = (Z1.conj() + S[0, 0] * Z1) * (1 - S[1, 1]) + cross * Z1 # A numerator
T[0, 1, :] = (Z1.conj() + S[0, 0] * Z1) * (Z1.conj() + S[1, 1] * Z2) - cross * Z1 * Z2 # B numerator
T[1, 0, :] = (1 - S[0, 0]) * (1 - S[1, 1]) - cross # C numerator
T[1, 1, :] = (1 - S[0, 0]) * (Z2.conj() + S[1, 1] * Z2) + cross * Z2 # D numerator
det = 2 * S[1, 0] * numpy.sqrt(Z1.real * Z2.real)
T /= det
return T
def generalize_S(
S: NDArray[numpy.complex128],
r0: float,
z0: NDArray[numpy.complex128],
) -> NDArray[numpy.complex128]:
g = (z0 - r0) / (z0 + r0)
D = numpy.diag((1 - g) / numpy.abs(1 - g.conj()) * numpy.sqrt(1 - numpy.abs(g * g.conj())))
G = numpy.diag(g)
U = numpy.eye(S.shape[-1]).reshape((S.ndim - 2) * (1,) + (S.shape[-2], S.shape[-1]))
S_gen = pinv(D.conj()) @ (S - G.conj()) @ pinv(U - G @ S) @ D
return S_gen
def change_R0(
S: NDArray[numpy.complex128],
r1: float,
r2: float,
) -> NDArray[numpy.complex128]:
g = (r2 - r1) / (r2 + r1)
U = numpy.eye(S.shape[-1]).reshape((S.ndim - 2) * (1,) + (S.shape[-2], S.shape[-1]))
G = U * g
S_r2 = (S - G) @ pinv(U - G @ S)
return S_r2
# Zc = numpy.sqrt(B / C)
# gamma = numpy.arccosh(A) / L_TL
# n_eff = -1j * gamma * c_light / (2 * pi * f)
# n_eff_grp = n_eff + f * diff(n_eff) / diff(f)
# attenuation = (1 - S[0, 0] * S[0, 0].conj()) / (S[1, 0] * S[1, 0].conj())
# R = numpy.real(gamma * Zc)
# C = numpy.real(gamma / Zc)
# L = numpy.imag(gamma * Zc) / (-1j * 2 * pi * f)
# G = numpy.imag(gamma / Zc) / (-1j * 2 * pi * f)