在 savefig 和 close() 之后，Matplotlib 不释放内存

Question

I have a piece of code that works fine looping once or twice but eventually it builds up memory. I tried to locate the memory leakage with memory_profiler and this is the result:

row_nr    Memory_usage    Memory_diff    row_text
 470     52.699 MiB     0.000 MiB      ax.axis('off')
 471     167.504 MiB    114.805 MiB    fig.savefig('figname.png', dpi=600)
 472     167.504 MiB    0.000 MiB      fig.clf()
 473     109.711 MiB    -57.793 MiB    plt.close()
 474     109.711 MiB    0.000 MiB      gc.collect()`

I created the figure like this: fig, ax = plt.subplots()

Any suggestion where the 109 - 52 = 57 MiB went?

I am using python 3.3.

Answer 1

# Clear the current axes.
plt.cla() 
# Clear the current figure.
plt.clf() 
# Closes all the figure windows.
plt.close('all')

Hope this can help you

Answer 2

plt.ioff()在笔记本中为我工作，否则plt.close(fig) 。

Answer 3

# Clear the current axes.
plt.cla() 
# Clear the current figure.
plt.clf() 
# Closes all the figure windows.
plt.close('all')   
plt.close(fig)
gc.collect()

This worked for me. Just put these lines at the end of the loop!

Answer 4

Taken from here: Matplotlib errors result in a memory leak. How can I free up that memory?

Which has original ref: https://www.mail-archive.com/matplotlib-users@lists.sourceforge.net/msg11809.html

To get ax and figure do:

instead of:

import matplotlib.pyplot as plt
fig,ax = plt.subplots(1)

use:

from matplotlib import figure
fig = figure.Figure()
ax = fig.subplots(1)

Also no need to do plt.close() or anything. It worked for me.