import numpy as np
import matplotlib.pyplot as plt
from matplotlib.lines import Line2D
[ドキュメント]
def main():
plt.rcParams['font.family'] = 'MS Gothic'
plt.rcParams['font.size'] = 16
theta_deg = 60
theta = np.deg2rad(theta_deg)
v = np.cos(theta)
gamma = 1.0 / np.sqrt(1 - v**2)
origin_shift = np.array([1.0, 1.0, 1.0])
a, b = 0.5, 1 / 3
L = 2 * max(a, b)
x_axis = np.array([L, 0, 0])
y_axis = np.array([0, L, 0])
t_axis = np.array([0, 0, L])
x_p_axis = gamma * np.array([L, 0, -v * L])
y_p_axis = np.array([0, L, 0])
t_p_axis = gamma * np.array([-v * L, 0, L])
rect_rel = [
[0, 0, 0],
[a, 0, 0],
[a, b, 0],
[0, b, 0],
[0, 0, 0],
]
x_rect, y_rect, t_rect = zip(*[
(origin_shift[0] + x, origin_shift[1] + y, origin_shift[2] + t)
for x, y, t in rect_rel
])
x_p_rect = [gamma * (x - v * t) for x, t in zip(x_rect, t_rect)]
y_p_rect = list(y_rect)
t_p_rect = [gamma * (t - v * x) for x, t in zip(x_rect, t_rect)]
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
ax.plot([0, x_axis[0]], [0, x_axis[1]], [0, x_axis[2]], color='blue', linewidth=2)
ax.plot([0, y_axis[0]], [0, y_axis[1]], [0, y_axis[2]], color='skyblue', linewidth=2)
ax.plot([0, t_axis[0]], [0, t_axis[1]], [0, t_axis[2]], color='blue', linestyle='--', linewidth=2)
ax.plot([0, x_p_axis[0]], [0, x_p_axis[1]], [0, x_p_axis[2]], color='red', linewidth=2)
ax.plot([0, y_p_axis[0]], [0, y_p_axis[1]], [0, y_p_axis[2]], color='salmon', linewidth=2)
ax.plot([0, t_p_axis[0]], [0, t_p_axis[1]], [0, t_p_axis[2]], color='red', linestyle='--', linewidth=2)
ax.plot(x_rect, y_rect, t_rect, color='blue', linewidth=2)
ax.plot(x_p_rect, y_p_rect, t_p_rect, color='red', linewidth=2)
ax.set_xlabel('x')
ax.set_ylabel('y')
ax.set_zlabel('t')
ax.set_xlim([0, origin_shift[0] + a + 0.2])
ax.set_ylim([0, origin_shift[1] + b + 0.2])
ax.set_zlim([
min(0, min(t_p_rect) - 0.2),
max(origin_shift[2] + b + 0.2, t_p_axis[2] + 0.2)
])
legend_elements = [
Line2D([0], [0], color='blue', lw=2, label='静止系 x 軸'),
Line2D([0], [0], color='skyblue', lw=2, label='静止系 y 軸'),
Line2D([0], [0], color='blue', lw=2, linestyle='--', label='静止系 t 軸'),
Line2D([0], [0], color='red', lw=2, label="運動系 x' 軸"),
Line2D([0], [0], color='salmon', lw=2, label="運動系 y' 軸"),
Line2D([0], [0], color='red', lw=2, linestyle='--', label="運動系 t' 軸"),
Line2D([0], [0], color='blue', lw=2, label="静止系の矩形"),
Line2D([0], [0], color='red', lw=2, label="運動系の矩形"),
]
ax.legend(handles=legend_elements, fontsize=14, loc='upper left')
plt.title(
f"長方形を (1,1,1) にシフト＋座標軸表示 "
f"(θ={theta_deg}°, v/c={v:.2f})",
pad=20
)
plt.show()
if __name__ == "__main__":
main()