Running numpy from cygwin

Question

I am running a windows machine have installed Python 2.5. I also used the windows installer to install NumPy.

This all works great when I run the Python (command line) tool that comes with Python.

However, if I run cygwin and then run Python from within, it cannot find the numpy package.

What environment variable do I need to set? What value should it be set to?

Answer 1

Cygwin comes with its own version of Python, so it's likely that you have two Python installs on your system; one that installed under Windows and one which came with Cygwin.

To test this, try opening a bash prompt in Cygwin and typing which python to see where the Python executable is located. If it says /cygdrive/c/Python25/python.exe or something similar then you'll know you're running the Windows executable. If you see /usr/local/bin/python or something like that, then you'll know that you're running the Cygwin version.

I recommend opening a DOS prompt and running Python from there when you need interactive usage. This will keep your two Python installs nicely separate (it can be very useful to have both; I do this on my own machine). Also, you may have some problems running a program designed for Windows interactive console use from within a Cygwin shell.

Answer 2

You're running a separate copy of python provided by cygwin.

You can run /cygdrive/c/python25/python (or wherever you installed it) to get your win32 one, or just install another copy of numpy.

Answer 3

Ensure that PYTHONPATH has NumPy. Refer The Module Search Path (section 6.1.2) and Modifying Python's Search Path (section 4.1).

Answer 4

numpy built for windows is not compatible with cygwin python. You have to build it by yourself on cygwin.