我很难再现下面的代码，我非常想要一个演示文稿，虽然我理解梯度下降是如何工作的，我不知道animation.FuncAnimation函数有什么问题。我花了4个小时找到问题的解决方案，但不幸的是我不能。下面是我试图重现的代码（我使用jupyter-notebook）
%matplotlib inline
import math,os,sys,numpy as np
from numpy.random import random
from matplotlib import pyplot as plt, rcParams, animation, rc
from __future__ import print_function, division
from ipywidgets import interact, interactive, fixed
from ipywidgets.widgets import *
rc('animation', html='html5')
rcParams['figure.figsize'] = 3,3
%precision 4
np.set_printoptions(precision=4, linewidth=100)
def lin(a,x,b): return a * x + b
a = 3.
b = 8.
n = 30
x = random(n)
y = lin(a,x,b)
plt.scatter(x,y)
def sse(y, y_pred): return ((y-y_pred)**2).sum()
def loss(y, a, x, b): return sse(y, lin(a, x, b))
def avg_loss(y, a, x, b): return np.sqrt(loss(y, a, x, b)/n)
a_guess = -1
b_guess = 1
avg_loss(y, a_guess, x, b_guess)
lr = 0.01
#d[(y-(a*x+b))**2, b] = 2 (y_pred - y)
#d[(y -(a*x+b)) **2, a] = x * dy/db
def upd():
global a_guess, b_guess
y_pred = lin(a_guess, x, b_guess)
dydb = 2 * (y_pred - y)
dyda = x * dydb
a_guess -= lr*dyda.mean()
b_guess -= lr*dydb.mean()
fig = plt.figure(dpi=100, figsize=(5,5))
plt.scatter(x,y)
line, = plt.plot(x, lin(a_guess, x, b_guess))
plt.close()
def animate(i):
line.set_ydata(lin(a_guess, x, b_guess))
for i in range(10): upd()
return line,
ani = animation.FuncAnimation(fig, animate, np.arange(0, 40), interval=100)
ani
但是当我运行它时，我得到以下错误，
ValueError Traceback (most recent call last)
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/IPython/core/formatters.pyc in __call__(self, obj)
309 method = get_real_method(obj, self.print_method)
310 if method is not None:
--> 311 return method()
312 return None
313 else:
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in _repr_html_(self)
1233 fmt = rcParams['animation.html']
1234 if fmt == 'html5':
-> 1235 return self.to_html5_video()
1236
1237
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in to_html5_video(self)
1207 bitrate=rcParams['animation.bitrate'],
1208 fps=1000. / self._interval)
-> 1209 self.save(f.name, writer=writer)
1210
1211 # Now open and base64 encode
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in save(self, filename, writer, fps, dpi, codec, bitrate, extra_args, metadata, extra_anim, savefig_kwargs)
1061 # TODO: See if turning off blit is really necessary
1062 anim._draw_next_frame(d, blit=False)
-> 1063 writer.grab_frame(**savefig_kwargs)
1064
1065 # Reconnect signal for first draw if necessary
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/contextlib.pyc in __exit__(self, type, value, traceback)
33 value = type()
34 try:
---> 35 self.gen.throw(type, value, traceback)
36 raise RuntimeError("generator didn't stop after throw()")
37 except StopIteration, exc:
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in saving(self, *args, **kw)
287 yield self
288 finally:
--> 289 self.finish()
290
291 def _run(self):
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in finish(self)
307 def finish(self):
308 'Finish any processing for writing the movie.'
--> 309 self.cleanup()
310
311 def grab_frame(self, **savefig_kwargs):
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in cleanup(self)
346 def cleanup(self):
347 'Clean-up and collect the process used to write the movie file.'
--> 348 out, err = self._proc.communicate()
349 self._frame_sink().close()
350 verbose.report('MovieWriter -- '
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in communicate(self, input, timeout)
925
926 try:
--> 927 stdout, stderr = self._communicate(input, endtime, timeout)
928 finally:
929 self._communication_started = True
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in _communicate(self, input, endtime, orig_timeout)
1711 if _has_poll:
1712 stdout, stderr = self._communicate_with_poll(input, endtime,
-> 1713 orig_timeout)
1714 else:
1715 stdout, stderr = self._communicate_with_select(input, endtime,
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in _communicate_with_poll(self, input, endtime, orig_timeout)
1767 select_POLLIN_POLLPRI = select.POLLIN | select.POLLPRI
1768 if self.stdout:
-> 1769 register_and_append(self.stdout, select_POLLIN_POLLPRI)
1770 stdout = self._fd2output[self.stdout.fileno()]
1771 if self.stderr:
/home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in register_and_append(file_obj, eventmask)
1746 poller = select.poll()
1747 def register_and_append(file_obj, eventmask):
-> 1748 poller.register(file_obj.fileno(), eventmask)
1749 self._fd2file[file_obj.fileno()] = file_obj
1750
ValueError: I/O operation on closed file
<matplotlib.animation.FuncAnimation at 0x7f085e3c0fd0>
寻求帮助!!!
提前致谢 ：）
对我来说同样的问题。
我的解决方案是安装最新的ffmpeg
sudo apt-get update install ffmpeg
我有同样的问题。我正在使用我用conda安装的ffmpeg。我不得不删除它：
conda remove ffmpeg
然后我使用apt安装它：
sudo apt-get install fmpeg
好像conda版本有问题。
在Ubuntu 18.04.2上对我来说同样的问题。我删除了conda之后安装了最新的ffmpeg版本，它工作正常