Thread Subject: Basic fitting Problem

how can i know the the exact values of a linear fit??

i.e i have to plot the best fit to some noisy data but i want to know what are the values of the best fit line, besides getting them from the equation by calculation


cheers

"Mahmood " <tornido2@hotmail.com> wrote in message <hm2jcv$iqp$1@fred.mathworks.com>...
> how can i know the the exact values of a linear fit??
>
> i.e i have to plot the best fit to some noisy data but i want to know what are the values of the best fit line, besides getting them from the equation by calculation
>
>
> cheers

help polyfit
help polyval

John

if i have a plot like V shape, can i fit a line thro the first line and thro othe one at the same time ( not for both of them at once ) ?

tahnx



"John D'Errico" <woodchips@rochester.rr.com> wrote in message <hm2kep$o0c$1@fred.mathworks.com>...
> "Mahmood " <tornido2@hotmail.com> wrote in message <hm2jcv$iqp$1@fred.mathworks.com>...
> > how can i know the the exact values of a linear fit??
> >
> > i.e i have to plot the best fit to some noisy data but i want to know what are the values of the best fit line, besides getting them from the equation by calculation
> >
> >
> > cheers
>
> help polyfit
> help polyval
>
> John

You could just use the first half of your V shape to do the fitting
(thus generating one line) and do another fit for the second half of
your V.

You could write a small script to detect change in slope if you cannot
predict where the V will actually happen in your data.

"Mahmood " <tornido2@hotmail.com> wrote in message <hm2n31$ard$1@fred.mathworks.com>...
> if i have a plot like V shape, can i fit a line thro the first line and thro othe one at the same time ( not for both of them at once ) ?
>

If you have the proper tools, you can.

If you have the optimization toolbox, then you can download
my SLM tools from the file exchange. It can do this.

Or do you have the curve fitting toolbox?

John