Re: Problem of polyfit

[Paul Kienzle]

On Oct 7, 2005, at 12:05 AM, Dmitri A. Sergatskov wrote:

> Tetsuro KURITA wrote:
>
> > Following is an example which show that polyfit.m does not works well.
>
> You would get a very good fit if you normalize your data
>
> x = (x-mean(x))/(max(x)-min(x))
> and the same with y.

I've modified wpolyfit so that

        [p,s,mu] = wpolyfit(x,y,dy,n)

first centers and scales x by mu = [mean(x),std(x)].  I've used std(x) 
rather than max(x)-min(x) for compatibility.

The fit is a whole lot nicer when you do this :-)

- Paul



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