I'm on an Ubuntu 14.04.
I would have expected doing:
sudo apt-get install python-numpy
would've worked but it isn't the case...
The way I tried to check is by doing locate blas and found nothing that seemed relevant.
I would like a solution that doesn't involve me compiling from source.
The ideal solution is something that uses the ubuntu repos.
In Ubuntu 14.04 and later, blas and lapack are installed as part of python-scipy and python3-scipy, so you need to install python-scipy. In Ubuntu 18.04 and earlier open the terminal and type:
sudo apt install python-scipy
This command will also install libblas3 (Basic Linear Algebra Subprograms reference implementations, shared library) and liblapack3 (Library of linear algebra routines 3 - shared version) as dependencies, and it will also install python-numpy as a dependency if you don't already have it installed.