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

[Kamilche <klachemin@xxxxxxxxxxx>]

Magnus Lie Hetland wrote:
...
> print second[argmin(dist(first, second[..., NewAxis]), 0)]

Thanks so much for your help.  I'm trying to get it running in Python 
2.3, but I'm getting the following error:

>>>
Traceback (most recent call last):
  File "C:/Documents and Settings/Administrator/Desktop/numarray 
distance.py", line 27, in ?
    print second[Numeric.argmin(dist(first, second[..., 
Numeric.NewAxis]), 0)]
IndexError: invalid index
>>>

Here's the code that I've modified, trying to get it to work in Numeric:

#-----------------------------------------------------------

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((a - b)**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 second[Numeric.argmin(dist(first, second[..., Numeric.NewAxis]), 0)]