Error while using curve fitting toolbox

I've been trying to use the curve fitting toolbox to do a pretty simple fit. However, after I create a data set, choose the type of fit, and click apply, I get the error:

"Fit could not be computed due to error:

Too many output arguments."

This happens no matter what data I use or what fit I use; I've even tried exactly following the demos provided in help, loading census and fitting a curve to that, with the same result.

I'm using Version 7.8.0.347, R2009a. I checked for updates and it claimed there were none.

Does anyone know what might be causing this?

Thank you so much!

[Star Strider]

What do your data look like and what model do you want to fit? It might be easier to do programmatic curve fitting with 'lsqcurvefit', 'nlinfit' or one of the others.

[Sean de Wolski]

Please post the code.

[Claire]

@Sean de Wolski: There's no code involved, I'm just using the curve-fitting GUI that is launched when you enter cftool. The error shows up when I try to fit any function to any set of data.

@Star Strider: I'm trying to fit a falling exponential. I've already moved on to fit it by other methods, but this bug is really bothering me as it shows up no matter what data I use or what curve I try to fit it to (I've tried numerous sets of data).

Have you heard of anything like this happening?

[Sean de Wolski]

Could you post a screenshot? Anything you can do will help.

Do you have duplicate data points in your data vectors?

[Claire]

Here's a screenshot: http://i49.tinypic.com/34rahww.jpg Same exact error no matter what the data and fit.

I don't have any duplicate data points.

Thanks for taking the time to look at this!

[Sean de Wolski]

If you use:

x = 1:10;
y = .34*exp(-.1*x)

And then do the y = a*exp(b*x) fit, with this dataset, do you get the error?

[Claire]

Yes, same error: http://i48.tinypic.com/2vafity.jpg

[Sean de Wolski]

This seems more like a path issue with something important being shadowed.

Answer 1

[Sean de Wolski]

Do you by any chance have another function shadowing fit?

which -all fit

If you run:

dbstop if error

at the command line, and then cause the error. Where does the debugger stop. What was it trying to do when it errored?

[Claire]

It seems I did have another function shadowing fit. That fixed the problem.

Thank you so much for all your help! I really appreciate it.

[Sean de Wolski]

Excellent; Welcome to MATLAB Answers!