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Re: [pygame] Need Help with Distance Algorithm in Numeric



Thanks, I appreciate that! :-) But even so, the output I'm getting is as follows:

>>>
[[10 10 10]
 [10 10 10]
 [10 10 10]]
>>>

I would have thought it would be more like:

[[20 20 20]
 [10 10 10]
 [50 50 50]]



Code follows:
---------------------

import Numeric

# Your distance function, for measuring how similar two RGB triples
# are. I'm just using plain ol' Euclidean distance here. Note that it
# returns the pairwise distances for all elements in a and b (which
# must have the same shapes).
def dist(a, b):
    "Euclidean distance"
    return Numeric.sqrt(sum((b - a)**2, -1))


# In order to compare two arrays of different sizes, I'll just add a # new axis (to get "all-against-all" comparisons). Then I use argmin # to get the indices of the smallest distances and use the result as # an index array in the second array, returning an array with the # shape of the first array but with elements from the second:

first = Numeric.array([[10, 20, 30],
               [ 0,  0,  1],
               [50, 60, 50]])

second = Numeric.array([[10, 10, 10],
                [20, 20, 20],
                [30, 30, 30],
                [40, 40, 40],
                [50, 50, 50]])

print Numeric.take(second, Numeric.argmin(dist(first, second[..., Numeric.NewAxis]), 0))