[Numpy-discussion] argmin and unsigned types

Robert Kern rkern at ucsd.edu
Thu Oct 21 12:22:20 CDT 2004


argmin locates the minimum by finding the maximum of the negative of the 
input. Unfortunately, for unsigned arrays, the negative has nothing to 
do with the actual numerical negative.

Example:

 >>> from numarray import *
 >>> a = arange(10).astype(UInt8)
 >>> print a
[0 1 2 3 4 5 6 7 8 9]
 >>> print -a
[  0 255 254 253 252 251 250 249 248 247]
 >>> argmin(a)
1

We need a separate argmin to handle these arrays properly.

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
  Are the graves of dreams allowed to die."
   -- Richard Harter




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