meanas/meanas/fdtd/boundaries.py

67 lines
2.1 KiB
Python

"""
Boundary conditions
#TODO conducting boundary documentation
"""
from typing import Tuple, Any, List
from ..fdmath import fdfield_t, fdfield_updater_t
def conducting_boundary(direction: int,
polarity: int
) -> Tuple[fdfield_updater_t, fdfield_updater_t]:
dirs = [0, 1, 2]
if direction not in dirs:
raise Exception('Invalid direction: {}'.format(direction))
dirs.remove(direction)
u, v = dirs
if polarity < 0:
boundary_slice = [slice(None)] * 3 # type: List[Any]
shifted1_slice = [slice(None)] * 3 # type: List[Any]
boundary_slice[direction] = 0
shifted1_slice[direction] = 1
def en(e: fdfield_t) -> fdfield_t:
e[direction][boundary_slice] = 0
e[u][boundary_slice] = e[u][shifted1_slice]
e[v][boundary_slice] = e[v][shifted1_slice]
return e
def hn(h: fdfield_t) -> fdfield_t:
h[direction][boundary_slice] = h[direction][shifted1_slice]
h[u][boundary_slice] = 0
h[v][boundary_slice] = 0
return h
return en, hn
if polarity > 0:
boundary_slice = [slice(None)] * 3
shifted1_slice = [slice(None)] * 3
shifted2_slice = [slice(None)] * 3 # type: List[Any]
boundary_slice[direction] = -1
shifted1_slice[direction] = -2
shifted2_slice[direction] = -3
def ep(e: fdfield_t) -> fdfield_t:
e[direction][boundary_slice] = -e[direction][shifted2_slice]
e[direction][shifted1_slice] = 0
e[u][boundary_slice] = e[u][shifted1_slice]
e[v][boundary_slice] = e[v][shifted1_slice]
return e
def hp(h: fdfield_t) -> fdfield_t:
h[direction][boundary_slice] = h[direction][shifted1_slice]
h[u][boundary_slice] = -h[u][shifted2_slice]
h[u][shifted1_slice] = 0
h[v][boundary_slice] = -h[v][shifted2_slice]
h[v][shifted1_slice] = 0
return h
return ep, hp
raise Exception('Bad polarity: {}'.format(polarity))