feat: menambahkan pendulum

implementation/physics/pendulum.py

@@ -0,0 +1,100 @@
+# https://en.wikipedia.org/wiki/Pendulum
+import numpy as np
+import matplotlib.pyplot as plt
+from matplotlib.animation import FuncAnimation
+
+
+def parameter(g=9.8, L=1.0, a=float, b=float) -> float:
+    time_step = a / b
+    time_stap = np.linspace(0, a, b)
+    return g, L, time_step, time_stap
+
+
+def full_pendulum(g, L, theta, theta_velocity, time_step):
+    """
+    fungsi untuk menghitung persamaan pendulum.
+    """
+    theta_acceleration = -(g / L) * np.sin(theta)
+    theta_velocity += time_step * theta_acceleration
+    theta += time_step * theta_velocity
+    return theta, theta_velocity
+
+
+def calculate_pendulum() -> float:
+    """
+    Melakukan kalkulasi pendulum
+    """
+    theta = [np.radians(90)]
+    theta_velocity = 0
+
+    for _ in time_stap:
+        theta_new, theta_velocity = full_pendulum(
+            g, L, theta[-1], theta_velocity, time_step
+        )
+        theta.append(theta_new)
+
+    # persamaan proyeksi panjang tali
+    x = L * np.sin(theta)
+    y = -L * np.cos(theta)
+    return x, y
+
+
+def setup_axis(axis) -> None:
+    """
+    Setup sumbu x dan y.
+    """
+    axis.set_xlim(-L - 0.2, L + 0.2)
+    axis.set_ylim(-L - 0.2, L)
+    axis.grid()
+    return axis
+
+
+def create_plot_elements(axis) -> None:
+    """
+    Membuat elemen plot yang akan dianimasu.
+    """
+    (rod_line,) = axis.plot([], [], lw=2)
+    (mass_point,) = axis.plot([], [], marker="o", markersize=10)
+    (trace,) = axis.plot([], [], "-", lw=1, alpha=0.6)
+    return rod_line, mass_point, trace
+
+
+def animate(frame, x, y, rod_line, mass_point, trace) -> None:
+    """
+    Fungsi ini berguna untuk mengambil setiap hasil hitungan
+    dan menjadikan setiap hitungan frame.
+    """
+    rod_line.set_data([0, x[frame]], [0, y[frame]])
+    mass_point.set_data([x[frame]], [y[frame]])
+    trace.set_data(x[:frame], y[:frame])
+    return rod_line, mass_point, trace
+
+
+if __name__ == "__main__":
+    g, L, time_step, time_stap = parameter(a=20, b=300)
+    x, y = calculate_pendulum()
+    fig, axis = plt.subplots()
+    axis = setup_axis(axis)
+    rod_line, mass_point, trace = create_plot_elements(axis)
+
+    def init():
+        """
+        Parameter awal.
+        """
+        rod_line.set_data([], [])
+        mass_point.set_data([], [])
+        trace.set_data([], [])
+        return rod_line, mass_point, trace
+
+    animation = FuncAnimation(
+        fig=fig,
+        func=animate,
+        fargs=(x, y, rod_line, mass_point, trace),
+        init_func=init,
+        frames=len(time_stap),
+        interval=25,
+        blit=True,
+    )
+
+    print(animation)
+    plt.show()