[Octave-bug-tracker] [bug #50365] Wrong distance results from kmeans () and wrong centers

[Georg Wiora]

URL:
  <http://savannah.gnu.org/bugs/?50365>

                 Summary: Wrong distance results from kmeans () and wrong
centers
                 Project: GNU Octave
            Submitted by: gwiora
            Submitted on: Tue 21 Feb 2017 10:06:57 AM CET
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: gwiora
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.2.0
        Operating System: Any

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Details:

The kmeans() function from statisics package V1.3.0. does return wrong center
positions and wrong center distances.

I am using a 3-d data set and found at least one bug in code review of
kmeans.m but fixing it did non give the correct results.

The value returned for "dist" result is probably the sum of squares of
coordinate differences. But should be the euclidian distance at least when
'distance'='sqEuclidean' is set. Octave and matlab documentation both state
that the result should be euclidian distance.

When comparing cluster centers returned they do not match the points
associated with the index results. Something seems to be serverly screwed up
here. I will come back here when i can provide a test function with synthetic
data.




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