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import unittest
import parameterized
import numpy as np
import meep as mp
class TestPMLCylindrical(unittest.TestCase):
@classmethod
def setUp(cls):
cls.resolution = 25 # pixels/um
cls.s = 5.0
cls.dpml_r = 1.0
cls.dpml_z = 1.0
cls.cell_size = mp.Vector3(
cls.s + cls.dpml_r,
0,
cls.s + 2 * cls.dpml_z,
)
cls.fcen = 1.0
@parameterized.parameterized.expand(
[
(0.0, 0.04, False),
(-1.0, 0, False),
(2.0, 0.14, False),
(3.0, 0.17, True),
]
)
def test_pml_cyl(
self, m: float, rpos: float, accurate_fields_near_cylorigin: bool = False
):
"""Verifies that the z-PML properly attenuates fields at r=0.
Args:
m: exp(imϕ) angular dependence of the fields.
rpos: position of source along R direction.
accurate_fields_near_cylorigin: whether to compute more accurate
fields near r=0 for |m| > 1.
"""
pml_layers = [
mp.PML(self.dpml_r, direction=mp.R),
mp.PML(self.dpml_z, direction=mp.Z),
]
sources = [
mp.Source(
src=mp.GaussianSource(self.fcen, fwidth=0.1 * self.fcen),
center=mp.Vector3(rpos, 0, 0),
component=mp.Er,
),
]
sim = mp.Simulation(
resolution=self.resolution,
cell_size=self.cell_size,
dimensions=mp.CYLINDRICAL,
m=m,
sources=sources,
boundary_layers=pml_layers,
accurate_fields_near_cylorigin=accurate_fields_near_cylorigin,
)
if accurate_fields_near_cylorigin and abs(m) > 1:
sim.Courant = 1 / (abs(m) + 0.6)
flux_plus_z = sim.add_flux(
self.fcen,
0,
1,
mp.FluxRegion(
center=mp.Vector3(
0.5 * self.s,
0,
0.5 * self.s,
),
size=mp.Vector3(self.s, 0, 0),
),
)
flux_plus_r = sim.add_flux(
self.fcen,
0,
1,
mp.FluxRegion(
center=mp.Vector3(self.s, 0, 0),
size=mp.Vector3(0, 0, self.s),
),
)
flux_minus_z = sim.add_flux(
self.fcen,
0,
1,
mp.FluxRegion(
center=mp.Vector3(
0.5 * self.s,
0,
-0.5 * self.s,
),
size=mp.Vector3(self.s, 0, 0),
weight=-1.0,
),
)
sim.run(until_after_sources=50.94)
prev_flux = [
mp.get_fluxes(flux_plus_z)[0],
mp.get_fluxes(flux_plus_r)[0],
mp.get_fluxes(flux_minus_z)[0],
]
for t in [142.15, 214.64, 365.32]:
sim.run(until_after_sources=t)
cur_flux = [
mp.get_fluxes(flux_plus_z)[0],
mp.get_fluxes(flux_plus_r)[0],
mp.get_fluxes(flux_minus_z)[0],
]
cur_flux_str = ", ".join(f"{c:.8f}" for c in cur_flux)
flux_tot = sum(cur_flux)
print(f"flux:, {sim.meep_time()}, {cur_flux_str}, {flux_tot:.8f}")
# Check that the flux is converged with runtime long after the
# source has turned off. This verifies the correctness of the
# z-PML at r=0 for m=0, ±1 which involve special field-update
# equations.
places = 6 if mp.is_single_precision() else 7
for i in range(len(cur_flux)):
self.assertAlmostEqual(
prev_flux[i],
cur_flux[i],
places=places,
)
prev_flux[i] = cur_flux[i]
if __name__ == "__main__":
unittest.main()
|
