MATLAB Central Newsreader - Fitting in Matlab

Fitting in Matlab

Alexander — Fri, 27 Mar 2009 11:03:01 -0400

Hello,

I use a student version of Matlab R2007a, and I have a question about fitting. The student version comes without the Curve Fitting Toolbox. However, there is a way of intuitive GUI fitting, but it's very limited: In my version, if I go to Tools --> Basic fitting (in any figure window), I can for example choose linear fitting. Unfortunately, only one dataset can be fitted simultaneously, and there is no way to exclude bad points from the fit.

I have to do a lot of fitting regularly (mostly linear regression), and in most problems I require to fit several datasets in one figure, as well as to be able to exclude points in a dataset from fitting. Do you know a good way to do that (apart from coding every fit by hand)?

Matlab is really wonderful for manipulating data (recorded in physical experiments), it's also wonderful for plotting, so I guess there must be some way do some good fitting with it. I'd really hate to have to change to other tools like Origin oder Igor Pro, which by the way do not even have native Linux versions.

That's why I'm really curious about your replies!

Alexander

Re: Fitting in Matlab

Steven Lord — Fri, 27 Mar 2009 13:31:13 -0400

"Alexander" <alexander.erlich@gmail.com> wrote in message
news:gqibp5$5dm$1@fred.mathworks.com...
> Hello,
>
> I use a student version of Matlab R2007a, and I have a question about
> fitting. The student version comes without the Curve Fitting Toolbox.
> However, there is a way of intuitive GUI fitting, but it's very limited:
> In my version, if I go to Tools --> Basic fitting (in any figure window),
> I can for example choose linear fitting. Unfortunately, only one dataset
> can be fitted simultaneously, and there is no way to exclude bad points
> from the fit.
>
> I have to do a lot of fitting regularly (mostly linear regression), and in
> most problems I require to fit several datasets in one figure, as well as
> to be able to exclude points in a dataset from fitting. Do you know a good
> way to do that (apart from coding every fit by hand)?
>
> Matlab is really wonderful for manipulating data (recorded in physical
> experiments), it's also wonderful for plotting, so I guess there must be
> some way do some good fitting with it. I'd really hate to have to change
> to other tools like Origin oder Igor Pro, which by the way do not even
> have native Linux versions.

While the Student Version does not include Curve Fitting Toolbox by default,
it is available as an add-on product.

http://www.mathworks.com/academia/student_version/companion.html

If you're interested in purchasing this toolbox, go to the Store website at
the top of the page I linked above or contact Customer Service.

--
Steve Lord
slord@mathworks.com

Re: Fitting in Matlab

someone — Fri, 27 Mar 2009 13:43:01 -0400

"Alexander" <alexander.erlich@gmail.com> wrote in message <gqibp5$5dm$1@fred.mathworks.com>...
> Hello,
>
> I use a student version of Matlab R2007a, and I have a question about fitting. The student version comes without the Curve Fitting Toolbox. However, there is a way of intuitive GUI fitting, but it's very limited: In my version, if I go to Tools --> Basic fitting (in any figure window), I can for example choose linear fitting. Unfortunately, only one dataset can be fitted simultaneously, and there is no way to exclude bad points from the fit.
>
> I have to do a lot of fitting regularly (mostly linear regression), and in most problems I require to fit several datasets in one figure, as well as to be able to exclude points in a dataset from fitting. Do you know a good way to do that (apart from coding every fit by hand)?
>
> Matlab is really wonderful for manipulating data (recorded in physical experiments), it's also wonderful for plotting, so I guess there must be some way do some good fitting with it. I'd really hate to have to change to other tools like Origin oder Igor Pro, which by the way do not even have native Linux versions.
>
> That's why I'm really curious about your replies!
>
> Alexander

You can download EzyFit from the MATLAB FEX at:

http://www.mathworks.com/matlabcentral/fileexchange/10176

(Its a free curve fitting toolbox.)