Matplotlib OverflowError: Allocated too many blocks

Question

I am plotting three sets of roughly 20 time series. Each time series has 1.8 million points and I am plotting them separately. In order to reduce execution time (because I found out that the figure() function is quite time consuming), I open one figure only, plot and then clean it for the next time series. Something like: ``` import matplotlib.pyplot as plt fig = plt.figure() # open a figure for plotting for v in range(nfigs): # here I build the x and y vectors from the raw data # and also the figname string plt.plot(x, y, linewidth=0.3) plt.title('a title') plt.xlabel('x-label') plt.ylabel('y-label') plt.grid() plt.draw() plt.savefig(figname) plt.clf() plt.close() # close the figure after the job is done ``` All the plots are saved ok except for one in particular in all the data sets which gives me the following error (edited the file paths for privacy): ``` Traceback (most recent call last): File "", line 1, in File "~\AppData\Local\Continuum\Anaconda\lib\site-packag…

Accepted Answer

You can try to change the value of `agg.path.chunksize` (10000-100000) in the `matplotlibrc` file or during run time in `matplotlib.rcParams`. It causes the renderer to plot paths in chunks rather than the whole path at once; but according to the docs it might cause artifacts. See the sample `matplotlibrc` file at http://matplotlib.org/1.3.1/users/customizing.html for some more information.

Matplotlib OverflowError: Allocated too many blocks

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