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From Dmitriy Lyubimov <dlie...@gmail.com>
Subject Re: standardize data for PCA
Date Fri, 01 Mar 2013 20:21:45 GMT
No, there's no option to pre-scale it w.r.t. variance. But (I think) the
definition of PCA doesn't require it. More over, in fact, in many cases one
wants to preserve euclidean distances proportions between data points in
the dimensionally reduced output, in which case it wouldn't make sense to
scale it.

Can you perhaps elaborate a little on your reason for scaling input for PCA?


On Fri, Mar 1, 2013 at 6:30 AM, Tamas Jambor <jamborta@gmail.com> wrote:

> Hi,
>
> just wondering if there is a way to standardize data for SSVD (ie
> (x-mean)/sd)? I understand that using the PCA option would centralize the
> matrix per column mean, but it seems that there is no option to standardize
> it.
>
> thanks,
> Tamas
>

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