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From: "John D'Errico" <woodchips@rochester.rr.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Plotting 3-D Surface & Surface Fitting
Date: Mon, 4 Aug 2008 05:00:04 +0000 (UTC)
Organization: John D'Errico (1-3LEW5R)
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"Sudha` N" <sudhanatarajan@gmail.com> wrote in message 
<g75pui$90r$1@fred.mathworks.com>...
> 
> 
> > If your true goal was that equation,
> > then you should fit it to your original data.
> 
> John - Thanks. Yes my true goal is the equation, but I
> needed a nice graphical representation of my data too. Using
> gridfit was very quick and easy to do it. 
> 
> What is the best and fastest way to model an equation 
> for my data using matlab? 
> 
> Please provide me some pointers and I can read up from
> there.
> 
> Thanks.

The problem is, there is NO best way, nor
is there a terribly fast way that is any good.
Even in one dimension, finding the function
that generates a simple curve is a often
difficult process. It very much helps if you
have some prior knowledge as to the correct
mathematical form for your model. Without
that knowledge, it becomes a total guessing
game.

Of course, someone will probably be tempted
to suggest polynomials, as my own polyfitn
(also on the fex) can do the fitting. However,
while this is a fast solution, polynomial
models have their limits, and this does not
yield some simple relationship.

I'm sorry not to be of much help here.

John