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From Lance Norskog <goks...@gmail.com>
Subject Re: A Kabsch rotation is almost there
Date Tue, 06 Sep 2011 03:54:24 GMT
Found it- the moral is one I already knew: use real data (in this case,
generated wisely).

This is an interesting beast; it may be useful in some of the Mahout zones
of interest. Kabsch takes N pairs of points and creates a rotation matrix
which translates pair A [1] -> A[2], B[1] -> B[2], etc. It works in any
number of dimensions. Thus, it may be interesting to establish "interesting"
bags of words (like synonym phrases) as pairs, then rotate across linguistic
frames of reference. I implemented it for visualization.

Lance

On Sat, Sep 3, 2011 at 2:22 AM, Lance Norskog <goksron@gmail.com> wrote:

>
> https://github.com/LanceNorskog/LSH-Hadoop/blob/master/extras/mahout/src/working/KabshRotation.java
>
> This is an implementation from an article on Wikipedia, which never lies.
>
> http://en.wikipedia.org/wiki/Kabsch_algorithm
>
> The rotation outputs are way too far off. It has 3 points to rotate 2
> dimensions, so that seems like enough to do a good job. The 'Delta' vectors
> are the difference between A rotated to B, v.s. B.
>
> --
> Lance Norskog
> goksron@gmail.com
>
>


-- 
Lance Norskog
goksron@gmail.com

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