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"""3D and 2D Waves module."""
from __future__ import annotations
from typing import Iterable, Optional
from manim import *
__all__ = [
"LinearWave",
"RadialWave",
"StandingWave",
]
try:
# For manim < 0.15.0
from manim.mobject.opengl_compatibility import ConvertToOpenGL
except ModuleNotFoundError:
# For manim >= 0.15.0
from manim.mobject.opengl.opengl_compatibility import ConvertToOpenGL
class RadialWave(Surface, metaclass=ConvertToOpenGL):
def __init__(
self,
*sources: Optional[np.ndarray],
wavelength: float = 1,
period: float = 1,
amplitude: float = 0.1,
x_range: Iterable[float] = [-5, 5],
y_range: Iterable[float] = [-5, 5],
**kwargs,
) -> None:
"""A 3D Surface with waves moving radially.
Parameters
----------
sources
The sources of disturbance.
wavelength
The wavelength of the wave.
period
The period of the wave.
amplitude
The amplitude of the wave.
x_range
The range of the wave in the x direction.
y_range
The range of the wave in the y direction.
kwargs
Additional parameters to be passed to :class:`~Surface`.
Examples
--------
.. manim:: RadialWaveExampleScene
class RadialWaveExampleScene(ThreeDScene):
def construct(self):
self.set_camera_orientation(60 * DEGREES, -45 * DEGREES)
wave = RadialWave(
LEFT * 2 + DOWN * 5, # Two source of waves
RIGHT * 2 + DOWN * 5,
checkerboard_colors=[BLUE_D],
stroke_width=0,
)
self.add(wave)
wave.start_wave()
self.wait()
wave.stop_wave()
"""
self.wavelength = wavelength
self.period = period
self.amplitude = amplitude
self.time = 0
self.kwargs = kwargs
self.sources = sources
super().__init__(
lambda u, v: np.array([u, v, self._wave_z(u, v, sources)]),
u_range=x_range,
v_range=y_range,
**kwargs,
)
def _wave_z(self, u: float, v: float, sources: Iterable[np.ndarray]) -> float:
z = 0
for source in sources:
x0, y0, _ = source
z += self.amplitude * np.sin(
(2 * PI / self.wavelength) * ((u - x0) ** 2 + (v - y0) ** 2) ** 0.5
- 2 * PI * self.time / self.period
)
return z
def _update_wave(self, mob: Mobject, dt: float) -> None:
self.time += dt
mob.match_points(
Surface(
lambda u, v: np.array([u, v, self._wave_z(u, v, self.sources)]),
u_range=self.u_range,
v_range=self.v_range,
**self.kwargs,
)
)
def start_wave(self):
"""Animate the wave propagation."""
self.add_updater(self._update_wave)
def stop_wave(self):
"""Stop animating the wave propagation."""
self.remove_updater(self._update_wave)
class LinearWave(RadialWave):
def __init__(
self,
wavelength: float = 1,
period: float = 1,
amplitude: float = 0.1,
x_range: Iterable[float] = [-5, 5],
y_range: Iterable[float] = [-5, 5],
**kwargs,
) -> None:
"""A 3D Surface with waves in one direction.
Parameters
----------
wavelength
The wavelength of the wave.
period
The period of the wave.
amplitude
The amplitude of the wave.
x_range
The range of the wave in the x direction.
y_range
The range of the wave in the y direction.
kwargs
Additional parameters to be passed to :class:`~Surface`.
Examples
--------
.. manim:: LinearWaveExampleScene
class LinearWaveExampleScene(ThreeDScene):
def construct(self):
self.set_camera_orientation(60 * DEGREES, -45 * DEGREES)
wave = LinearWave()
self.add(wave)
wave.start_wave()
self.wait()
wave.stop_wave()
"""
super().__init__(
ORIGIN,
wavelength=wavelength,
period=period,
amplitude=amplitude,
x_range=x_range,
y_range=y_range,
**kwargs,
)
def _wave_z(self, u: float, v: float, sources: Iterable[np.ndarray]) -> float:
return self.amplitude * np.sin(
(2 * PI / self.wavelength) * u - 2 * PI * self.time / self.period
)
class StandingWave(ParametricFunction):
def __init__(
self,
n: int = 2,
length: float = 4,
period: float = 1,
amplitude: float = 1,
**kwargs,
) -> None:
"""A 2D standing wave.
Parameters
----------
n
Harmonic number.
length
The length of the wave.
period
The time taken for one full oscillation.
amplitude
The maximum height of the wave.
kwargs
Additional parameters to be passed to :class:`~ParametricFunction`.
Examples
--------
.. manim:: StandingWaveExampleScene
from manim_physics import *
class StandingWaveExampleScene(Scene):
def construct(self):
wave1 = StandingWave(1)
wave2 = StandingWave(2)
wave3 = StandingWave(3)
wave4 = StandingWave(4)
waves = VGroup(wave1, wave2, wave3, wave4)
waves.arrange(DOWN).move_to(ORIGIN)
self.add(waves)
for wave in waves:
wave.start_wave()
self.wait()
"""
self.n = n
self.length = length
self.period = period
self.amplitude = amplitude
self.time = 0
self.kwargs = {**kwargs}
super().__init__(
lambda t: np.array([t, amplitude * np.sin(n * PI * t / length), 0]),
t_range=[0, length],
**kwargs,
)
self.shift([-self.length / 2, 0, 0])
def _update_wave(self, mob: Mobject, dt: float) -> None:
self.time += dt
mob.become(
ParametricFunction(
lambda t: np.array(
[
t,
self.amplitude
* np.sin(self.n * PI * t / self.length)
* np.cos(2 * PI * self.time / self.period),
0,
]
),
t_range=[0, self.length],
**self.kwargs,
).shift(self.wave_center + [-self.length / 2, 0, 0])
)
def start_wave(self):
self.wave_center = self.get_center()
self.add_updater(self._update_wave)
def stop_wave(self):
self.remove_updater(self._update_wave)
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