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Return angular wavenumbers, and remove r0 arg (leaving only rmin)

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Jan Petykiewicz 2025-01-14 22:02:19 -08:00
parent 006833acf2
commit 6a56921c12
1 changed files with 23 additions and 21 deletions
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42
meanas/fdfd/waveguide_cyl.py
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@ -28,7 +28,6 @@ def cylindrical_operator(
omega: complex,
dxes: dx_lists_t,
epsilon: vfdfield_t,
r0: float,
rmin: float,
) -> sparse.spmatrix:
"""
@ -51,8 +50,7 @@ def cylindrical_operator(
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
r0: Radius of curvature at x=0
rmin: Radius at the left edge of the simulation domain
rmin: Radius at the left edge of the simulation domain (minimum 'x')
Returns:
Sparse matrix representation of the operator
@ -61,13 +59,7 @@ def cylindrical_operator(
Dfx, Dfy = deriv_forward(dxes[0])
Dbx, Dby = deriv_back(dxes[1])
ra = rmin + dxes[0][0] / 2.0 + numpy.cumsum(dxes[1][0]) # Radius at Ex points
rb = rmin + numpy.cumsum(dxes[0][0]) # Radius at Ey points
ta = ra / r0
tb = rb / r0
Ta = sparse.diags(vec(ta[:, None].repeat(dxes[0][1].size, axis=1)))
Tb = sparse.diags(vec(tb[:, None].repeat(dxes[1][1].size, axis=1)))
Ta, Tb = dxes2T(dxes=dxes, rmin=rmin)
eps_parts = numpy.split(epsilon, 3)
eps_x = sparse.diags(eps_parts[0])
@ -103,10 +95,9 @@ def solve_modes(
omega: complex,
dxes: dx_lists_t,
epsilon: vfdfield_t,
r0: float,
rmin: float,
mode_margin: int = 2,
) -> tuple[vcfdfield_t, NDArray[numpy.complex64]]:
) -> tuple[vcfdfield_t, NDArray[numpy.complex128]]:
"""
TODO: fixup
Given a 2d (r, y) slice of epsilon, attempts to solve for the eigenmode
@ -118,12 +109,12 @@ def solve_modes(
dxes: Grid parameters [dx_e, dx_h] as described in meanas.fdmath.types.
The first coordinate is assumed to be r, the second is y.
epsilon: Dielectric constant
r0: Radius of curvature for the simulation. This should be the minimum value of
rmin: Radius of curvature for the simulation. This should be the minimum value of
r within the simulation domain.
Returns:
e_xys: NDArray of vfdfield_t specifying fields. First dimension is mode number.
wavenumbers: list of wavenumbers
angular_wavenumbers: list of wavenumbers in 1/rad units.
"""
#
@ -131,15 +122,17 @@ def solve_modes(
#
dxes_real = [[numpy.real(dx) for dx in dxi] for dxi in dxes]
A_r = cylindrical_operator(numpy.real(omega), dxes_real, numpy.real(epsilon), r0=r0, rmin=rmin)
A_r = cylindrical_operator(numpy.real(omega), dxes_real, numpy.real(epsilon), rmin=rmin)
eigvals, eigvecs = signed_eigensolve(A_r, max(mode_numbers) + mode_margin)
e_xys = eigvecs[:, -(numpy.array(mode_numbers) + 1)].T
keep_inds = -(numpy.array(mode_numbers) + 1)
e_xys = eigvecs[:, keep_inds].T
eigvals = eigvals[keep_inds]
#
# Now solve for the eigenvector of the full operator, using the real operator's
# eigenvector as an initial guess for Rayleigh quotient iteration.
#
A = cylindrical_operator(omega, dxes, epsilon, r0=r0, rmin=rmin)
A = cylindrical_operator(omega, dxes, epsilon, rmin=rmin)
for nn in range(len(mode_numbers)):
eigvals[nn], e_xys[nn, :] = rayleigh_quotient_iteration(A, e_xys[nn, :])
@ -147,7 +140,15 @@ def solve_modes(
wavenumbers = numpy.sqrt(eigvals)
wavenumbers *= numpy.sign(numpy.real(wavenumbers))
return e_xys, wavenumbers
# Wavenumbers assume the mode is at rmin, which is unlikely
# Instead, return the wavenumber in inverse radians
angular_wavenumbers = wavenumbers * rmin
order = angular_wavenumbers.argsort()[::-1]
e_xys = e_xys[order]
angular_wavenumbers = angular_wavenumbers[order]
return e_xys, angular_wavenumbers
def solve_mode(
@ -164,8 +165,9 @@ def solve_mode(
**kwargs: passed to `solve_modes()`
Returns:
(e_xy, wavenumber)
(e_xy, angular_wavenumber)
"""
kwargs['mode_numbers'] = [mode_number]
e_xys, wavenumbers = solve_modes(*args, **kwargs)
return e_xys[0], wavenumbers[0]
return e_xys[0], angular_wavenumbers[0]