[SciPy-User] unravel_index for pdist?

[Benjamin Root]

Hello,

I typically use pdist() from scipy.spatial.distance to keep some of my
scripts lean wrt memory usage.  However, determining which pairs of points a
distance value refers to is a bit tricky.  I was wondering if a
"punravel_index()" function might be welcomed?

Here is my algorithm I came up with to perform this action for a single
result.  I haven't tested it for anything more general than that. *pntCnt*
is the number of points that pdist() was used for.  *index* is an index from
a function like "np.argmax(pdist(p))".

    rowcnts = np.cumsum(xrange(pntCnt - 1, 0, -1))
    row = np.searchsorted(rowcnts, index)
    col = pntCnt - (rowcnts[row] - index)

At the very least, I hope that this is helpful to anybody else using pdist.

Ben Root
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