test_anim.ipynb

Kernel: Python 3

from __future__ import print_function, division

%matplotlib inline

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import animation

from matplotlib import rc


# this notebook works with
rc('animation', html='jshtml')

# and until a recent update, it also worked with
rc('animation', html='html5')

# but now it produces the error below

N = 10
array = np.zeros((N, N))

def init_func():
    """Called at the beginning of an animation."""
    pass

def animate_func(i):
    """Draws one frame of the animation."""
    a = np.zeros((N, N))
    a[i, i] = 1

    image.set_array(a)
    return (image,)

fig = plt.gcf()
a = np.zeros((N, N))
a[0, 0] = 1
image = plt.imshow(a)
anim = animation.FuncAnimation(fig,
                               animate_func,
                               init_func=init_func,
                               frames=N,
                               interval=20)

anim

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
~/anaconda3/lib/python3.6/site-packages/IPython/core/formatters.py in __call__(self, obj)
    343             method = get_real_method(obj, self.print_method)
    344             if method is not None:
--> 345                 return method()
    346             return None
    347         else:
~/anaconda3/lib/python3.6/site-packages/matplotlib/animation.py in _repr_html_(self)
   1482         fmt = rcParams['animation.html']
   1483         if fmt == 'html5':
-> 1484             return self.to_html5_video()
   1485         elif fmt == 'jshtml':
   1486             return self.to_jshtml()
~/anaconda3/lib/python3.6/site-packages/matplotlib/animation.py in to_html5_video(self, embed_limit)
   1411                                 bitrate=rcParams['animation.bitrate'],
   1412                                 fps=1000. / self._interval)
-> 1413                 self.save(f.name, writer=writer)
   1414 
   1415             # Now open and base64 encode
~/anaconda3/lib/python3.6/site-packages/matplotlib/animation.py in save(self, filename, writer, fps, dpi, codec, bitrate, extra_args, metadata, extra_anim, savefig_kwargs)
   1258                         # TODO: See if turning off blit is really necessary
   1259                         anim._draw_next_frame(d, blit=False)
-> 1260                     writer.grab_frame(**savefig_kwargs)
   1261 
   1262         # Reconnect signal for first draw if necessary
~/anaconda3/lib/python3.6/contextlib.py in __exit__(self, type, value, traceback)
     97                 value = type()
     98             try:
---> 99                 self.gen.throw(type, value, traceback)
    100             except StopIteration as exc:
    101                 # Suppress StopIteration *unless* it's the same exception that
~/anaconda3/lib/python3.6/site-packages/matplotlib/animation.py in saving(self, fig, outfile, dpi, *args, **kwargs)
    235             yield self
    236         finally:
--> 237             self.finish()
    238 
    239 
~/anaconda3/lib/python3.6/site-packages/matplotlib/animation.py in finish(self)
    367     def finish(self):
    368         '''Finish any processing for writing the movie.'''
--> 369         self.cleanup()
    370 
    371     def grab_frame(self, **savefig_kwargs):
~/anaconda3/lib/python3.6/site-packages/matplotlib/animation.py in cleanup(self)
    406     def cleanup(self):
    407         '''Clean-up and collect the process used to write the movie file.'''
--> 408         out, err = self._proc.communicate()
    409         self._frame_sink().close()
    410         verbose.report('MovieWriter -- '
~/anaconda3/lib/python3.6/subprocess.py in communicate(self, input, timeout)
    841 
    842             try:
--> 843                 stdout, stderr = self._communicate(input, endtime, timeout)
    844             finally:
    845                 self._communication_started = True
~/anaconda3/lib/python3.6/subprocess.py in _communicate(self, input, endtime, orig_timeout)
   1503                     selector.register(self.stdin, selectors.EVENT_WRITE)
   1504                 if self.stdout:
-> 1505                     selector.register(self.stdout, selectors.EVENT_READ)
   1506                 if self.stderr:
   1507                     selector.register(self.stderr, selectors.EVENT_READ)
~/anaconda3/lib/python3.6/selectors.py in register(self, fileobj, events, data)
    349 
    350         def register(self, fileobj, events, data=None):
--> 351             key = super().register(fileobj, events, data)
    352             poll_events = 0
    353             if events & EVENT_READ:
~/anaconda3/lib/python3.6/selectors.py in register(self, fileobj, events, data)
    235             raise ValueError("Invalid events: {!r}".format(events))
    236 
--> 237         key = SelectorKey(fileobj, self._fileobj_lookup(fileobj), events, data)
    238 
    239         if key.fd in self._fd_to_key:
~/anaconda3/lib/python3.6/selectors.py in _fileobj_lookup(self, fileobj)
    222         """
    223         try:
--> 224             return _fileobj_to_fd(fileobj)
    225         except ValueError:
    226             # Do an exhaustive search.
~/anaconda3/lib/python3.6/selectors.py in _fileobj_to_fd(fileobj)
     37         except (AttributeError, TypeError, ValueError):
     38             raise ValueError("Invalid file object: "
---> 39                              "{!r}".format(fileobj)) from None
     40     if fd < 0:
     41         raise ValueError("Invalid file descriptor: {}".format(fd))
ValueError: Invalid file object: <_io.BufferedReader name=49>

<matplotlib.animation.FuncAnimation at 0x7f4f0f772390>