ANN (Approximate Nearest Neighbor) is a C++ library for both exact and approximate nearest neighbor searching in arbitrarily high dimensions. I've been trying to use SWIG to wrap this library so I can use it in Python. Today I found out that someone had already done it!

The project is called scikits.ann. They even have an already-to-use egg file for OS X 10.5. Since my primary operating system is Leopard, I installed the egg file and tried it out. Everything worked great! I needed to use this library under Windows XP also, however, due to some things at work. Here's how I got everything working.

First of all, make sure you have Cygwin installed (with the MinGW32 tools). We'll be using Cygwin to compile ANN. Also make sure you have Python 2.5 for Windows XP installed and Numpy. You'll also need configobj, and obviously setuptools to be able to install the configobj egg. After all those files have been successfully installed, continue as follows (all these commands are within a Cygwin shell):

Compile and install ANN

• Download from http://www.cs.umd.edu/~mount/ANN/Files/1.1.1/ann_1.1.1.tar.gz
• Download the Windows XP Makefile from http://scipy.org/scipy/scikits/attachment/wiki/WindowsBuildInstructionsForAnn/annwinstuff.zip
• Untar ann:

$ tar xfvz ann_1.1.1.tar.gz

• Copy the annwinstuff.zip file into the ann_1.1.1 directory and unzip:

$ unzip annwinstuff.zip

• Edit the ANN.h header file:

$ vi include/ANN/ANN.h

• Replace lines 75 and 77 with:

#define DLL_API

• Build ANN with mingw:

$ mingw32-make -f Makefile.win

• Copy ANN includes to Cygwin includes:

$ cp -r include/ANN /usr/local/include/.

• Copy ANN library to Cygwin lib:

$ cp lib/ANN.lib /usr/local/lib/.

Compile and install AnnWrapper

• Download from http://pypi.python.org/packages/source/s/scikits.ann/scikits.ann-0.2.dev-r803.tar.gz
• Edit site.cfg:

$ vi site.cfg

• Change ANN_ROOT to:

ANN_ROOT = c:/cygwin/usr/local

• Build and install AnnWrapper:

$ /cygdrive/c/Python25/python.exe setup.py build_ext --inplace build -c mingw32 install

Hopefully you'll now have a working install of scikits.ann to use with the Windows version of Python 2.5! See the ANN documentation and the AnnWrapper documentation for information on how to use this module.