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Re: polyfit -> polyval problem
From: |
Ben Abbott |
Subject: |
Re: polyfit -> polyval problem |
Date: |
Wed, 22 Jun 2011 09:21:20 -0400 |
On Jun 22, 2011, at 9:16 AM, Sergei Steshenko wrote:
> Hello,
>
> I can't figure out what I an doing wrong in the following example:
>
> "
> octave:42> [p, s, mu] = polyfit ((1:10)(:), 2 * (1:10)(:), 1);
> octave:43> p
> p =
>
> 6.0553 11.0000
>
> octave:44> polyval(p, 1:10)
> ans =
>
> 17.055 23.111 29.166 35.221 41.277 47.332 53.387 59.442
> 65.498 71.553
>
I think the problem is with the syntax you're using for polyval. If "mu" is an
output for polyfit(), then it must be used as an input for polval().
octave:3> [p, s, mu] = polyfit ((1:10)(:), 2 * (1:10)(:), 1);
octave:4> polyval(p, 1:10, [], mu)
ans =
2.0000 4.0000 6.0000 8.0000 10.0000 12.0000 14.0000
16.0000 18.0000 20.0000
Ben