<p dir="auto">I was trying to import numpy but came out with this problem, i tried to reinstall numpy but it's still not working, any ideas?</p>
<p dir="auto">Here's the issue-</p>
<blockquote>
<blockquote>
<blockquote>
<p dir="auto">import numpy<br>
Traceback (most recent call last):<br>
File "/usr/local/lib/python3.5/dist-packages/numpy/core/<strong>init</strong>.py", line 17, in <br>
from . import multiarray<br>
File "/usr/local/lib/python3.5/dist-packages/numpy/core/multiarray.py", line 14, in <br>
from . import overrides<br>
File "/usr/local/lib/python3.5/dist-packages/numpy/core/overrides.py", line 7, in <br>
from numpy.core._multiarray_umath import (<br>
ImportError: /usr/local/lib/python3.5/dist-packages/numpy/core/_multiarray_umath.cpython-35m-arm-linux-gnueabihf.so: undefined symbol: cblas_sgemm</p>
</blockquote>
</blockquote>
</blockquote>
<p dir="auto">During handling of the above exception, another exception occurred:</p>
<p dir="auto">Traceback (most recent call last):<br>
File "&lt;pyshell#0&gt;", line 1, in <br>
import numpy<br>
File "/usr/local/lib/python3.5/dist-packages/numpy/<strong>init</strong>.py", line 142, in <br>
from . import core<br>
File "/usr/local/lib/python3.5/dist-packages/numpy/core/<strong>init</strong>.py", line 47, in <br>
raise ImportError(msg)<br>
ImportError:</p>
<p dir="auto">IMPORTANT: PLEASE READ THIS FOR ADVICE ON HOW TO SOLVE THIS ISSUE!</p>
<p dir="auto">Importing the numpy c-extensions failed.</p>
<ul dir="auto">
<li>
<p dir="auto">Try uninstalling and reinstalling numpy.</p>
</li>
<li>
<p dir="auto">If you have already done that, then:</p>
<ol dir="auto">
<li>Check that you expected to use Python3.5 from "/usr/bin/python3",<br>
and that you have no directories in your PATH or PYTHONPATH that can<br>
interfere with the Python and numpy version "1.17.2" you're trying to use.</li>
<li>If (1) looks fine, you can open a new issue at<br>
<a href="https://github.com/numpy/numpy/issues">https://github.com/numpy/numpy/issues</a>.  Please include details on:
<ul dir="auto">
<li>how you installed Python</li>
<li>how you installed numpy</li>
<li>your operating system</li>
<li>whether or not you have multiple versions of Python installed</li>
<li>if you built from source, your compiler versions and ideally a build log</li>
</ul>
</li>
</ol>
</li>
<li>
<p dir="auto">If you're working with a numpy git repository, try <code class="notranslate">git clean -xdf</code><br>
(removes all files not under version control) and rebuild numpy.</p>
</li>
</ul>
<p dir="auto">Note: this error has many possible causes, so please don't comment on<br>
an existing issue about this - open a new one instead.</p>
<p dir="auto">Original error was: /usr/local/lib/python3.5/dist-packages/numpy/core/_multiarray_umath.cpython-35m-arm-linux-gnueabihf.so: undefined symbol: cblas_sgemm</p>
<p dir="auto">This is on installing numpy on raspberry pi 3. I used the Noobs latest version and so using Raspbian stretch. Python was already installed, and I think numpy was already included. At the time, I think that import numpy was working well.<br>
I installed openCV and it didn't work for a while as I had not put some necessary modules, but finally got it to work. So far so good.<br>
Later I was trying to install matplotlib, and this didn't go very smoothly. I made a number of attempts where the message in the title was already flagged. I finally manage to get the import matplotlib to work, but then numpy stopped importing. Now I cannot import either matplotlib or numpy, despite having uninstalled numpy (pip3 uninstall numpy) and reinstalled:</p>
<p dir="auto">/home/pi/.local/lib/python3.5/site-packages/numpy/tests/test_warnings.py<br>
/home/pi/.local/lib/python3.5/site-packages/numpy/version.py<br>
Proceed (y/n)? y<br>
Successfully uninstalled numpy-1.16.1<br>
pi@raspberrypi:~ $ pip3 install numpy<br>
Collecting numpy<br>
Using cached <a href="https://www.piwheels.org/simple/numpy/numpy-1.16.1-cp35-cp35m-linux_armv7l.whl" rel="nofollow">https://www.piwheels.org/simple/numpy/numpy-1.16.1-cp35-cp35m-linux_armv7l.whl</a><br>
Installing collected packages: numpy<br>
Successfully installed numpy-1.16.1<br>
pi@raspberrypi:~ $</p>
<p dir="auto">Prior to uninstalling numpy, I did try to install without uninstalling, and downloaded the cached file mentioned.</p>
<p dir="auto">Now, I cannot import numpy or matplotlib and for both get a similar error and the message telling me to raise this new issue which I am doing now.</p>
<blockquote>
<blockquote>
<blockquote>
<p dir="auto">import numpy<br>
Traceback (most recent call last):<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/core/<strong>init</strong>.py", line 16, in <br>
from . import multiarray<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/core/multiarray.py", line 12, in <br>
from . import overrides<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/core/overrides.py", line 6, in <br>
from numpy.core._multiarray_umath import (<br>
ImportError: /home/pi/.local/lib/python3.5/site-packages/numpy/core/_multiarray_umath.cpython-35m-arm-linux-gnueabihf.so: undefined symbol: cblas_sgemm</p>
</blockquote>
</blockquote>
</blockquote>
<p dir="auto">During handling of the above exception, another exception occurred:</p>
<p dir="auto">Traceback (most recent call last):<br>
File "&lt;pyshell#0&gt;", line 1, in <br>
import numpy<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/<strong>init</strong>.py", line 142, in <br>
from . import core<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/core/<strong>init</strong>.py", line 47, in <br>
raise ImportError(msg)<br>
ImportError:</p>
<p dir="auto">IMPORTANT: PLEASE READ THIS FOR ADVICE ON HOW TO SOLVE THIS ISSUE!</p>
<p dir="auto">Importing the multiarray numpy extension module failed.  Most<br>
likely you are trying to import a failed build of numpy.<br>
Here is how to proceed:</p>
<ul dir="auto">
<li>If you're working with a numpy git repository, try <code class="notranslate">git clean -xdf</code><br>
(removes all files not under version control) and rebuild numpy.</li>
<li>If you are simply trying to use the numpy version that you have installed:<br>
your installation is broken - please reinstall numpy.</li>
<li>If you have already reinstalled and that did not fix the problem, then:
<ol dir="auto">
<li>
<p dir="auto">Check that you are using the Python you expect (you're using /usr/bin/python3),<br>
and that you have no directories in your PATH or PYTHONPATH that can<br>
interfere with the Python and numpy versions you're trying to use.</p>
</li>
<li>
<p dir="auto">If (1) looks fine, you can open a new issue at<br>
<a href="https://github.com/numpy/numpy/issues">https://github.com/numpy/numpy/issues</a>.  Please include details on:</p>
<ul dir="auto">
<li>how you installed Python</li>
<li>how you installed numpy</li>
<li>your operating system</li>
<li>whether or not you have multiple versions of Python installed</li>
<li>if you built from source, your compiler versions and ideally a build log</li>
</ul>
<p dir="auto">Note: this error has many possible causes, so please don't comment on<br>
an existing issue about this - open a new one instead.</p>
</li>
</ol>
</li>
</ul>
<p dir="auto">Original error was: /home/pi/.local/lib/python3.5/site-packages/numpy/core/_multiarray_umath.cpython-35m-arm-linux-gnueabihf.so: undefined symbol: cblas_sgemm</p>
<blockquote>
<blockquote>
<blockquote>
<p dir="auto">import matplotlib<br>
Traceback (most recent call last):<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/core/<strong>init</strong>.py", line 16, in <br>
from . import multiarray<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/core/multiarray.py", line 12, in <br>
from . import overrides<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/core/overrides.py", line 6, in <br>
from numpy.core._multiarray_umath import (<br>
ImportError: /home/pi/.local/lib/python3.5/site-packages/numpy/core/_multiarray_umath.cpython-35m-arm-linux-gnueabihf.so: undefined symbol: cblas_sgemm</p>
</blockquote>
</blockquote>
</blockquote>
<p dir="auto">During handling of the above exception, another exception occurred:</p>
<p dir="auto">Traceback (most recent call last):<br>
File "&lt;pyshell#1&gt;", line 1, in <br>
import matplotlib<br>
File "/home/pi/.local/lib/python3.5/site-packages/matplotlib/<strong>init</strong>.py", line 141, in <br>
from . import cbook, rcsetup<br>
File "/home/pi/.local/lib/python3.5/site-packages/matplotlib/cbook/<strong>init</strong>.py", line 33, in <br>
import numpy as np<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/<strong>init</strong>.py", line 142, in <br>
from . import core<br>
File "/home/pi/.local/lib/python3.5/site-packages/numpy/core/<strong>init</strong>.py", line 47, in <br>
raise ImportError(msg)<br>
ImportError:</p>
<p dir="auto">IMPORTANT: PLEASE READ THIS FOR ADVICE ON HOW TO SOLVE THIS ISSUE!</p>
<p dir="auto">Importing the multiarray numpy extension module failed.  Most<br>
likely you are trying to import a failed build of numpy.<br>
Here is how to proceed:</p>
<ul dir="auto">
<li>If you're working with a numpy git repository, try <code class="notranslate">git clean -xdf</code><br>
(removes all files not under version control) and rebuild numpy.</li>
<li>If you are simply trying to use the numpy version that you have installed:<br>
your installation is broken - please reinstall numpy.</li>
<li>If you have already reinstalled and that did not fix the problem, then:
<ol dir="auto">
<li>
<p dir="auto">Check that you are using the Python you expect (you're using /usr/bin/python3),<br>
and that you have no directories in your PATH or PYTHONPATH that can<br>
interfere with the Python and numpy versions you're trying to use.</p>
</li>
<li>
<p dir="auto">If (1) looks fine, you can open a new issue at<br>
<a href="https://github.com/numpy/numpy/issues">https://github.com/numpy/numpy/issues</a>.  Please include details on:</p>
<ul dir="auto">
<li>how you installed Python</li>
<li>how you installed numpy</li>
<li>your operating system</li>
<li>whether or not you have multiple versions of Python installed</li>
<li>if you built from source, your compiler versions and ideally a build log</li>
</ul>
<p dir="auto">Note: this error has many possible causes, so please don't comment on<br>
an existing issue about this - open a new one instead.</p>
</li>
</ol>
</li>
</ul>
<p dir="auto">Original error was: /home/pi/.local/lib/python3.5/site-packages/numpy/core/_multiarray_umath.cpython-35m-arm-linux-gnueabihf.so: undefined symbol: cblas_sgemm</p>
<p dir="auto">I hope this helps and that it will eventually contribute to making the installation of these two packages easier in the future.</p>
<p dir="auto">Thanks,</p>
<p dir="auto">Thomas</p>