[SciPy-User] kmeans
Keith Goodman
kwgoodman@gmail....
Fri Jul 23 18:48:52 CDT 2010
On Fri, Jul 23, 2010 at 4:00 PM, Benjamin Root <ben.root@ou.edu> wrote:
> The stopping condition uses the change in the distortion, not a non-squared
> distance. The distortion is already a sum of squares. The only place that
> a non-squared distance is used is in _py_vq_1d() which appears to be very
> old code and it has a raise error at the very first statement.
That's good news.
Another place that a non-squared distance is used is the return value:
>> import numpy as np
>> from scipy import cluster
>> v = np.array([1,2,3,4,10],dtype=float)
>> cluster.vq.kmeans(v, 1)
(array([ 4.]), 2.3999999999999999)
>> np.sqrt(np.dot(v-4, v-4) / 5.0)
3.1622776601683795 # Nope, not returned
>> np.absolute(v - 4).mean()
2.3999999999999999 # Yep, this one is returned
Is that a code bug or a doc bug?
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