Today I decided to install openCV to explore some image processing stuff I had been thinking about. This required that I upgrade my numpy install to a newer version. Windows is an awful environment to do things like this, so here is a guide to save myself the pain the next time I have to do this.

1. Install pip

The python package manager pip allows simple command line installation of python packages using a command something like this:

pip install <package name>

But if you don’t have it installed by default, as is the case for any python installs before version 2.7.8 and 3.3, you need to install it first. Download the file get-pip.py from here and run it at the command prompt with administrator privileges:

python get-pip.py

This will download and install pip to your local python install.

2. Download The Wheel

Pip will attempt to compile the desired python module on the fly, and on Windows that can lead to a lot of problems. The solution is to get the wheel file and direct pip to install from that, ensuring that the source files are correct for your hardware. A good resource for wheel files is here. The key is to download the correct file for your environment. I needed to upgrade numpy, so I used the file:

numpy-1.9.2+mkl-cp27-none-win32.whl

cp27 corresponds to the version of python you are running, in my case I use 2.7 and win32 indicates that I am using a 32 bit version of python.

3. Install The Package

Finally, at the shell, navigate to the folder where the wheel file was downloaded to, and install from it:

pip install numpy-1.9.2+mkl-cp27-none-win32.whl

If you give it an incorrect wheel file version it will give the following message:

<Filename> is not supported wheel on this platform

But if you use the correct file, it should upgrade or install the package as required. So now I can use numpy 1.9.2.