Matplotlib runs out of memory

Question

Here is the code that I'm using to plot many plots and save them, but it is eating up all of the available RAM and causes the notebook to crash. I tried adding fig.clf(), del fig, gc.collect, and yet nothing seems to work. I'm able to save only 38 figures around, then session gets crashed on Google Colab, since RAM gets full.

import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt

print(np.__version__) # 1.19.5
print(mpl.__version__) # 3.2.2, also tried with latest 3.4.1

x = np.arange(0, 280, 0.1)
y = np.sin(x)

for k in range(100):
  fig, ax = plt.subplots(6, 2, sharex = True)
  fig.set_size_inches(37.33, 21)

  for i in range(2):
    for j in range(6):
      ax[j][i].plot(x, y)

  fig.savefig(f'figure{k}.png', dpi = 300)
  plt.close(fig)

Answer 1

This is related to the inline backend. The memory leak can be avoided by explicitly switching to the agg backend. cross ref: matplotlib/issues/20067