def plot_underdamped_pendulum():
pendulum = Oscillator(alpha=0.8, radius=1)
time_steps = 400
time_max = 10.0
time = numpy.linspace(0, time_max, time_steps + 1)
plt.axes(xlim=(0, 10), ylim=(-0.2, 0.2))
trajectory = pendulum.get_trajectory(time_max, time_steps)
theta = [position for position, velocity in trajectory]
plt.plot(time, theta, "r")
def plot_theta_vs_theta_dash():
pendulum = Oscillator(alpha=0.8, radius=1)
time_steps = 400
time_max = 10.0
plt.axes(xlim=(-0.1, 0.1), ylim=(-0.25, 0.25))
trajectory = pendulum.get_trajectory(time_max, time_steps)
theta = [position for position, velocity in trajectory]
theta_dash = [velocity for position, velocity in trajectory]
plt.plot(theta, theta_dash, "b")
from matplotlib import animation
from matplotlib import pyplot as plt
from oscillator import Oscillator
fig = plt.figure()
ax = plt.axes(xlim=(-0.1, 0.1), ylim=(-0.2, 1))
pendulum_bob, = ax.plot([], [], lw=2, marker='o', color="r", markersize=30)
pendulum_rod, = ax.plot([], [], lw=2, color="black")
time_steps = 400
time_max = 10.0
pendulum = Oscillator()
trajectory = pendulum.get_trajectory(time_max, time_steps)
y = [position for position, velocity in trajectory]
x_coord = [math.sin(position) for position, velocity in trajectory]
y_coord = [(1 - math.cos(position)) for position, velocity in trajectory]
def init():
pendulum_bob.set_data([], [])
plt.title("Damped Pendulum Motion")
plt.xlabel("X", fontsize=13, family='monospace')
plt.ylabel("Y", fontsize=13, family='monospace')
return pendulum_bob,
def animate(i):
pendulum_bob.set_data(x_coord[i], y_coord[i])
from matplotlib import pyplot as plt
from oscillator import Oscillator
fig = plt.figure()
ax = plt.axes(xlim=(0, 10), ylim=(-0.22, 0.22))
theta_line, = ax.plot([], [], lw=2, color="green")
theta_dash_line, = ax.plot([], [], lw=2, color="blue")
time_steps = 400
time_max = 10.0
osc = Oscillator()
x = np.linspace(0, time_max, time_steps + 1)
trajectory = osc.get_trajectory(time_max, time_steps)
y = [position for position, velocity in trajectory]
y_dash = [velocity for position, velocity in trajectory]
def init():
theta_line.set_data([], [])
plt.xlabel("Time", fontsize=13, family='monospace')
plt.ylabel("Angular Displacement, Angular Velocity",
fontsize=13,
family='monospace')
plt.title("Angular Displacement and Angular Velocity v/s Time",
fontsize=13,
family='monospace')
blue_line = mlines.Line2D([], [],
def test_amplitude_decreases_when_friction_present(self):
oscillator = Oscillator(alpha=1.0, radius=1.0)
self.assertTrue(
oscillator.state[0] > oscillator.get_trajectory(10.0, 500)[-1][0])
def test_state_unchanged_after_zero_time(self):
oscillator = Oscillator()
self.assertListEqual(oscillator.state,
list(oscillator.get_trajectory(0, 1)[0]))
