Re: fit plane to xz axis of data
- To: mathgroup at smc.vnet.net
- Subject: [mg89685] Re: fit plane to xz axis of data
- From: Ray Koopman <koopman at sfu.ca>
- Date: Wed, 18 Jun 2008 04:23:11 -0400 (EDT)
- References: <g30399$mes$1@smc.vnet.net>
On Jun 14, 2:33 am, will parr <willpower... at hotmail.com> wrote:
> [...]
> Additionally, is it possible to compute a vector running parallel
> to the long side (long axis of the SVD plane) of the computed
> plane, originating at the mean (centroid) of the data, with a
> length of 1?
> [...]
v rotates the {x,y,z} axes to the principal axes of the centered
data: (#-m&/@data).v == u.w , which contains the projections of
the centered points onto their principal axes. u is orthonormal,
and w is diagonal, so you want u[[All,1]] .