<h2 dir="auto">Bug report</h2>
<p dir="auto">The PDF logo doesn't look quite right, viewed in Adobe Acrobat, Preview, and Google Chrome (on macOS). If you look closely at the center, there are some extra features there that don't show up in, for instance, the svg.</p>
<p dir="auto"><a href="https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/mpl-data/images/matplotlib.pdf">https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/mpl-data/images/matplotlib.pdf</a></p>
<p dir="auto">Maybe somebody should track down why the render of the PDF glitched? At least replace it with one that isn't glitchy?</p>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/458871/62189030-de384380-b322-11e9-9259-28bbf118c7f2.png"><img src="https://user-images.githubusercontent.com/458871/62189030-de384380-b322-11e9-9259-28bbf118c7f2.png" alt="image" style="max-width: 100%;"></a></p>
<p dir="auto">matplotlib.pyplot.spy does not work correctly for sparse matrices with a large number of entries (&gt;= 2**32). I would guess it has something to do with the value range of int32.</p>
<p dir="auto">An example that reproduces the bug is:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="import numpy as np
import scipy.sparse
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
n = 16
s = 2**n
A = scipy.sparse.coo_matrix(np.ones((s,s), dtype=np.int8))
plt.spy(A)
file = '/tmp/spy_{}.png'.format(n)
plt.savefig(file)"><pre class="notranslate"><code class="notranslate">import numpy as np
import scipy.sparse
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
n = 16
s = 2**n
A = scipy.sparse.coo_matrix(np.ones((s,s), dtype=np.int8))
plt.spy(A)
file = '/tmp/spy_{}.png'.format(n)
plt.savefig(file)
</code></pre></div>
<p dir="auto">For n = 16, spy shows only some entries.<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/2393560/15041512/d5aae93e-12bc-11e6-8914-4bb839c7f117.png"><img src="https://cloud.githubusercontent.com/assets/2393560/15041512/d5aae93e-12bc-11e6-8914-4bb839c7f117.png" alt="spy_16" style="max-width: 100%;"></a><br>
For n = 15 it works correctly.<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/2393560/15041505/d0300750-12bc-11e6-8240-0afdd63cdd02.png"><img src="https://cloud.githubusercontent.com/assets/2393560/15041505/d0300750-12bc-11e6-8240-0afdd63cdd02.png" alt="spy_15" style="max-width: 100%;"></a></p>
<p dir="auto">I have used Matplotlib 1.5.1 installed over pip with Python 3.5.1 on Linux.</p>