Matplotlib animation not working in IPython Notebook (blank plot)

Question

I've tried multiple animation sample codes and cannot get any of them working. Here's a basic one I've tried from the Matplotlib documentation:

""" A simple example of an animated plot """ import numpy as np import matplotlib.pyplot as plt import matplotlib.animation as animation  fig, ax = plt.subplots()  x = np.arange(0, 2*np.pi, 0.01)        # x-array line, = ax.plot(x, np.sin(x))  def animate(i):     line.set_ydata(np.sin(x+i/10.0))  # update the data     return line,  #Init only required for blitting to give a clean slate. def init():     line.set_ydata(np.ma.array(x, mask=True))     return line,  ani = animation.FuncAnimation(fig, animate, np.arange(1, 200), init_func=init,     interval=25, blit=True) plt.show() 

When I execute the above in an IPython Notebook, I just see a blank plot generated. I've tried running this from multiple servers (including Wakari), on multiple machines, using multiple browsers (Chrome, FF, IE).

I can save the animation to an mp4 file just fine and it looks good when played.

Any help is appreciated!

Answer 1

To summarize the options you have:

• Using display in a loop Use IPython.display.display(fig) to display a figure in the output. Using a loop you would want to clear the output before a new figure is shown. Note that this technique gives in general not so smooth resluts. I would hence advice to use any of the below.

  import matplotlib.pyplot as plt  import matplotlib.animation  import numpy as np  from IPython.display import display, clear_output    t = np.linspace(0,2*np.pi)  x = np.sin(t)    fig, ax = plt.subplots()  l, = ax.plot([0,2*np.pi],[-1,1])    animate = lambda i: l.set_data(t[:i], x[:i])    for i in range(len(x)):  animate(i)  clear_output(wait=True)  display(fig)    plt.show()

• %matplotlib notebook Use IPython magic %matplotlib notebook to set the backend to the notebook backend. This will keep the figure alive instead of displaying a static png file and can hence also show animations.
  Complete example:

  %matplotlib notebook  import matplotlib.pyplot as plt  import matplotlib.animation  import numpy as np    t = np.linspace(0,2*np.pi)  x = np.sin(t)    fig, ax = plt.subplots()  l, = ax.plot([0,2*np.pi],[-1,1])    animate = lambda i: l.set_data(t[:i], x[:i])    ani = matplotlib.animation.FuncAnimation(fig, animate, frames=len(t))    plt.show()

• %matplotlib tk Use IPython magic %matplotlib tk to set the backend to the tk backend. This will open the figure in a new plotting window, which is interactive and can thus also show animations.
  Complete example:

  %matplotlib tk  import matplotlib.pyplot as plt  import matplotlib.animation  import numpy as np    t = np.linspace(0,2*np.pi)  x = np.sin(t)    fig, ax = plt.subplots()  l, = ax.plot([0,2*np.pi],[-1,1])    animate = lambda i: l.set_data(t[:i], x[:i])    ani = matplotlib.animation.FuncAnimation(fig, animate, frames=len(t))    plt.show()

• Convert animation to mp4 video:

  from IPython.display import HTML HTML(ani.to_html5_video()) 

  or use plt.rcParams["animation.html"] = "html5" at the beginning of the notebook. This will require to have ffmpeg video codecs available to convert to HTML5 video. The video is then shown inline. This is therefore compatible with %matplotlib inline backend. Complete example:

  %matplotlib inline  import matplotlib.pyplot as plt  plt.rcParams["animation.html"] = "html5"  import matplotlib.animation  import numpy as np    t = np.linspace(0,2*np.pi)  x = np.sin(t)    fig, ax = plt.subplots()  l, = ax.plot([0,2*np.pi],[-1,1])    animate = lambda i: l.set_data(t[:i], x[:i])    ani = matplotlib.animation.FuncAnimation(fig, animate, frames=len(t))  ani

  %matplotlib inline  import matplotlib.pyplot as plt  import matplotlib.animation  import numpy as np    t = np.linspace(0,2*np.pi)  x = np.sin(t)    fig, ax = plt.subplots()  l, = ax.plot([0,2*np.pi],[-1,1])    animate = lambda i: l.set_data(t[:i], x[:i])    ani = matplotlib.animation.FuncAnimation(fig, animate, frames=len(t))    from IPython.display import HTML  HTML(ani.to_html5_video())

• Convert animation to JavaScript:

  from IPython.display import HTML HTML(ani.to_jshtml()) 

  or use plt.rcParams["animation.html"] = "jshtml" at the beginning of the notebook. This will display the animation as HTML with JavaScript. This highly compatible with most new browsers and also with the %matplotlib inline backend. It is available in matplotlib 2.1 or higher.
  Complete example:

  %matplotlib inline  import matplotlib.pyplot as plt  plt.rcParams["animation.html"] = "jshtml"  import matplotlib.animation  import numpy as np    t = np.linspace(0,2*np.pi)  x = np.sin(t)    fig, ax = plt.subplots()  l, = ax.plot([0,2*np.pi],[-1,1])    animate = lambda i: l.set_data(t[:i], x[:i])    ani = matplotlib.animation.FuncAnimation(fig, animate, frames=len(t))  ani

  %matplotlib inline  import matplotlib.pyplot as plt  import matplotlib.animation  import numpy as np    t = np.linspace(0,2*np.pi)  x = np.sin(t)    fig, ax = plt.subplots()  l, = ax.plot([0,2*np.pi],[-1,1])    animate = lambda i: l.set_data(t[:i], x[:i])    ani = matplotlib.animation.FuncAnimation(fig, animate, frames=len(t))    from IPython.display import HTML  HTML(ani.to_jshtml())