ANN wrapper (v0.2) now LGPL, OS X egg available

With help and suggestions from Rob Hetland, I've made many changes to the API of our Approximate Nearest Neighbor wrapper for scipy. The API is now hides much of the SWIG-yness of the old version and feels (I hope) more pythonic. On Rob's suggestion we've also added C++ code to make querying multiple points much faster. Because the ANN library is LGPL, I've relicensed our wrapper as LGPL to avoid any LGPL/BSD conflicts and have moved the wrapper to the scigpl namespace from scikits (too bad, scikits looks so much flashier).

I've also made an egg for OS X that statically links the ANN library. You should be able to install via (one line):

easy_install -f http://rieke-server.physiol.washington.edu/~barry/python scigpl.ann

Of course, you can still get it via the scikits SVN.

Here's how the new API looks:

>>> import scigpl.ann as ann

>>> import numpy as np

>>> k=ann.kdtree(np.array([[0.,0],[1,0],[1.5,2]]))

>>> k.knn([0,.2],1)
(array([[0]]), array([[ 0.04]]))

>>> k.knn([0,.2],2)
(array([[0, 1]]), array([[ 0.04, 1.04]]))

>>> k.knn([[0,.2],[.1,2],[3,1],[0,0]],2)
(array([[0, 1],
[2, 0],
[2, 1],
[1, 2]]), array([[ 0.04, 1.04],
[ 1.96, 4.01],
[ 3.25, 5. ],
[ 1. , 6.25]]))

>>> k.knn([[0,.2],[.1,2],[3,1],[0,0]],3)
(array([[ 0, 1, 2],
[ 2, 0, 1],
[ 2, 1, 0],
[ 1, 2, -1]]), array([[ 4.00000000e-002, 1.04000000e+000, 5.49000000e+000],
[ 1.96000000e+000, 4.01000000e+000, 4.81000000e+000],
[ 3.25000000e+000, 5.00000000e+000, 1.00000000e+001],
[ 1.00000000e+000, 6.25000000e+000, 1.79769313e+308]]))