def get_cached_image(preset_name, image_path):
"""
retrieve or transparently generate cache for full-sized image
"""
preset = get_preset(preset_name)
processor = imageprocessor_from_preset(preset)
cache = ImageCache(preset.output_dir)
img = cache.get_image(processor, image_path)
if not img:
img = CachedImage(processor.process(image_path).save().filename)
return img
def process_image(preset_name, filename):
return imageprocessor_from_preset(
get_preset(preset_name)).process(filename)
def visualize_fields(config):
"""Plot electric and magnetic fields for given configuration
Args:
config: Environment configuration
"""
ax3 = config["plane"]["axis"]
Z = config["plane"]["coordinate"]
axes = []
for i in range(3):
if i == ax3:
axes.append([Z])
else:
x_min, x_max = config["plot-bounds"]["min"][i], config[
"plot-bounds"]["max"][i]
x_min -= config["plot-margins"][i]
x_max += config["plot-margins"][i]
axis = np.linspace(x_min, x_max,
config["resolution"] * int(x_max - x_min))
axes.append(axis)
space = np.array(np.meshgrid(*axes))
axis_names = ["x", "y", "z"]
ax1, ax2 = {0: (1, 2), 1: (0, 2), 2: (0, 1)}[ax3]
e_field, b_field = np.zeros_like(space), np.zeros_like(space)
if "charges" in config:
charges = np.array(config["charges"])
def efield_charges(x):
E = np.zeros_like(x)
for charge in charges:
s = (x.T - charge[1:]).T
E += charge[0] * s / (np.linalg.norm(s, axis=0)**3 + 1e-6)
return E
e_field += efield_charges(space)
list_charge_densities = []
if "charge-densities" in config:
densities = config["charge-densities"]
for density_func in densities:
if density_func["preset"]:
rho = presets.get_preset(density_func)
else:
rho = construct_function(eval_safety, density_func["func"])
list_charge_densities.append(rho)
def integrand(z, y, x, Xz, Xy, Xx, axis):
X = np.array([Xx, Xy, Xz])
Y = np.array([x, y, z])
v = X - Y
return rho(z, y, x) * v[axis] / (np.linalg.norm(v)**3 + 1e-6)
def integrand2(y, x, Xz, Xy, Xx, axis, z, axis1, axis2, axis3):
Y = np.empty(3)
Y[axis1] = x
Y[axis2] = y
Y[axis3] = z
return integrand(Y[2], Y[1], Y[0], Xz, Xy, Xx, axis)
def integrand1(x, Xz, Xy, Xx, axis, y, z, axis1, axis2, axis3):
Y = np.empty(3)
Y[axis1] = x
Y[axis2] = y
Y[axis3] = z
return integrand(Y[2], Y[1], Y[0], Xz, Xy, Xx, axis)
def grid_integral(f, *bounds, args=(), dim=3):
if dim == 3:
return np.vectorize(lambda z, y, x: tplquad(
f, *bounds, args=(z, y, x, *args))[0]
if rho(z, y, x) == 0 else 0)
elif dim == 2:
return np.vectorize(lambda z, y, x: dblquad(
f, *bounds, args=(z, y, x, *args))[0])
elif dim == 1:
return np.vectorize(lambda z, y, x: quad(
f, *bounds, args=(z, y, x, *args))[0])
if density_func["func"] == presets.PRESET_DELTA and \
density_func["var"] in ["x", "y", "z"]:
val = density_func["value"]
axis1, axis2, delAxis = {
("x", 0): (1, 2, 0),
("x", 1): (2, 1, 0),
("x", 2): (1, 2, 0),
("y", 0): (2, 0, 1),
("y", 1): (0, 2, 1),
("y", 2): (0, 2, 1),
("z", 0): (1, 0, 2),
("z", 1): (0, 1, 2),
("z", 2): (0, 1, 2)
}[(density_func["var"], ax3)]
ax, ay = axes[axis1][0], axes[axis2][0]
bx, by = axes[axis1][-1], axes[axis2][-1]
for axis in range(3):
if axis == ax3:
continue
if delAxis == ax3:
# Technically this should never come up
# because the field is parallel to the
# ignored axis
e_field[axis] += grid_integral(integrand2,
ax,
bx,
ay,
by,
args=(axis, val, axis1,
axis2, delAxis),
dim=2)(space[2],
space[1],
space[0])
else:
e_field[axis] += grid_integral(
integrand1,
ax,
bx,
args=(axis, val, Z, axis1, delAxis, axis2),
dim=1)(space[2], space[1], space[0])
else:
ax, ay, az = axes[0][0], axes[1][0], axes[2][0]
bx, by, bz = axes[0][-1], axes[1][-1], axes[2][-1]
if ax == bx:
ax, bx = ay, by
elif ay == by:
ay, by = ax, bx
elif az == bz:
az, bz = ax, bx
for axis in range(3):
if axis == ax3:
continue
e_field[axis] += grid_integral(integrand,
ax,
bx,
ay,
by,
az,
bz,
args=(axis, ))(space[2],
space[1],
space[0])
# Determine overall charge density distribution
if len(list_charge_densities) > 0:
overall_charge_density = np.zeros_like(space[0])
for rho in list_charge_densities:
overall_charge_density += np.vectorize(rho)(space[2], space[1],
space[0])
if ax3 != 2:
ax1, ax2 = ax2, ax1
e_field = np.moveaxis(e_field, 2 - ax3, -1)
b_field = np.moveaxis(b_field, 2 - ax3, -1)
overall_charge_density = np.moveaxis(overall_charge_density, 1 - ax3,
-1)
# Generate field plots
for field_name, field in zip(["e", "b"], [e_field, b_field]):
config_name = f"{field_name}-field"
if config[config_name]["plot"]:
render_name = f"{field_name.upper()}-Field"
plt.figure(render_name)
# Plot charges
if "charges" in config:
for charge in config["charges"]:
xy = (charge[1 + ax1], charge[1 + ax2])
plt.plot(*xy,
'ro',
color=("red" if charge[0] > 0 else "blue"))
plt.annotate(f"{charge[0]} C",
xy=xy,
xytext=(10, 5),
ha='right',
textcoords='offset points')
# Plot charge densities
if len(list_charge_densities) > 0:
plt.contourf(axes[ax1],
axes[ax2],
overall_charge_density.T[0].T,
cmap=plt.cm.bwr)
# Plot field
fx, fy = field[ax1].T[0].T, field[ax2].T[0].T
color = 2 * np.log(np.hypot(fx, fy) + 1e-6)
try:
plt.streamplot(axes[ax1],
axes[ax2],
fx,
fy,
color=color,
cmap=plt.get_cmap(config["colormap"]))
except ValueError as e:
print(f"Failed to plot {render_name}: {e}")
# Plot labels
plt.title(f"{render_name} ({axis_names[ax3]} = {Z})")
plt.xlabel(axis_names[ax1])
plt.ylabel(axis_names[ax2])
# Output
if output_files[config_name] is not None:
plt.savefig(output_files[config_name])
else:
plt.savefig(f"{config['name']} {render_name}.png")
if config["show"]:
plt.show()
