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Re: 3D data set

• To: mathgroup at smc.vnet.net
• Subject: [mg51070] Re: 3D data set
• From: p-valko at tamu.edu (Peter Valko)
• Date: Sun, 3 Oct 2004 05:47:48 -0400 (EDT)
• References: <cjdq0q$ar3$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hi,
First I would try a two-parameter minimization of   
Sum[ (x- b Sin[a z])^2+(y - b Cos[a z])^2, go through points] 

If it works, I would look up the "error-in-variables" methods that is
a generalization of the least squares method for the case when all
variables (x,y,z) are corrupted by errors.

Peter


Giovanni Bellesia <giovanni.bellesia at ucd.ie> wrote in message news:<cjdq0q$ar3$1 at smc.vnet.net>...
> Dear all,
> 
> I have a general question regarding a topic which is not 
> completely new to the forum.
> I have a 3D data set (from a Monte Carlo simulation) which are supposed 
> to lay approximately on a helix.
> Does anybody knows a clear and efficient procedure to fit these points 
> to a regular, circular helix.
> I read something about this in a message dated may 2004 by D.L. but I 
> wasn't able to download the related files
> 
> Thanks
> 
> Giovanni