.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "matplotlib/plot_parabolic_reflector_anime.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_matplotlib_plot_parabolic_reflector_anime.py: parabolic reflector (animated) ==================== .. GENERATED FROM PYTHON SOURCE LINES 7-102 .. container:: sphx-glr-animation .. raw:: html

.. code-block:: default import numpy as np import matplotlib.pyplot as plt import matplotlib.animation as animation from collections import deque fig, ax = plt.subplots(1,1) def y(x): return x**2/2 def df(x,y): return np.array([-x, 1]) sample=10 plot_l = [] hist = [] hist_len = 40 ax.axis('off') fig.patch.set_alpha(0.) ax.plot(0, 0.5, 'ok', ms=10) for i in range(sample): point, = ax.plot([], [], '-', ms=10) trace, = ax.plot([], [], '-', lw=2, c=point.get_color()) hist_x, hist_y = deque(maxlen=hist_len), deque(maxlen=hist_len) plot_l.append(point) plot_l.append(trace) hist.append(hist_x) hist.append(hist_y) dt = 0.02 x0 = np.linspace(-1.5, 1.5, 10) y0 = np.array([2]*sample) p = np.array([x0,y0]) traj_x = [np.array([])]*sample traj_y = [np.array([])]*sample xx = np.linspace(-2, 2, 100) ax.plot(xx, y(xx), '-k',lw=3) ax.text(1.7,1.2, r"$y=\frac{x^2}{2}$",fontsize=15) for i, z in enumerate(zip(x0, y0)): vec = np.array([0,-1]) for t in range(180): z = z + dt*vec x0, y0 = z if y0 < y(x0): x0 = z[0] y0 = y(x0) n = df(x0, y0) pn = - np.dot(vec, n)/np.dot(n, n) * n vec = vec + 2*pn if np.all(np.abs(np.array([x0,y0]) - np.array([0,0.5])) < 0.02): vec = np.array([0,0]) traj_x[i] = np.append(traj_x[i], x0) traj_y[i] = np.append(traj_y[i], y0) def animate(i): for j in range(sample): thisx = traj_x[j][i] thisy = traj_y[j][i] if i == 0: hist[2*j].clear() hist[2*j+1].clear() hist[2*j].append(thisx) hist[2*j+1].append(thisy) plot_l[2*j].set_data(thisx, thisy) plot_l[2*j+1].set_data(hist[2*j], hist[2*j+1]) ani = animation.FuncAnimation(fig, animate, len(traj_x[0]), interval=dt*1000, # blit=True ) """ ani.save('anim_parabolic.mp4', # writer='pillow' writer="ffmpeg", # codec="png", savefig_kwargs={"transparent": True, 'facecolor': 'none'} ) """ plt.show() .. rst-class:: sphx-glr-timing **Total running time of the script:** ( 0 minutes 7.227 seconds) .. _sphx_glr_download_matplotlib_plot_parabolic_reflector_anime.py: .. only:: html .. container:: sphx-glr-footer sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: plot_parabolic_reflector_anime.py ` .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: plot_parabolic_reflector_anime.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_