Re: Find coefficients for a unified model for fitting negative and positive output

[Doug Stewart]

On Wed, Jan 30, 2019, 6:47 AM insafba <address@hidden wrote:

Thank you for replying,
actually, this is what I did, but when I assume that the radius values are
positive, I get a completely messy figure as below. but that's doesn't
matter. the problem is how to approach the max possible to the true value
(which is in my case 10) and how to recalculate the coefficients by
successive iterations until finding a satisfying result?
<http://octave.1599824.n4.nabble.com/file/t373159/fitting_with_leasqr_radiusallpositive.png>



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Sent from: http://octave.1599824.n4.nabble.com/Octave-General-f1599825.html

If your true data is a circle , then the radius is a constant and  should show up as a horizontal straight line.

Do you think  that the true radius is 10?

If you want to find a horizontal straight line you could put six or seven copies of your raw data end to end and then do a normal straight line approximation and see what you get.

You're raw data sure doesn't look like it's part of a pure Circle