fit() from Curve Fitting Toolbox not working even with examples from the documentation

I'm trying to use the fit() function from the curve fitting toolbox but it kept giving me an error saying "Data sizes are incompatible."

The script I'm using is directly from the documentation:

load franke
sf = fit([x, y],z,'poly23')
plot(sf,[x,y],z)

I tried it in MATLAB online and it worked perfectly, but not working in MATLAB R2021b. I tried updating it to R2022a which also didn't solve the problem. Not sure if this is a bug or I'm doing something wrong.

Answer 1

[Matt J]

Run the code inside a function,

>> myfunction

function myfunction

    load franke
    sf = fit([x, y],z,'poly23')
    plot(sf,[x,y],z)

end

[Wenlin]

This seemed to have worked. After running it in a function, it works both inside a function and just as script. Any idea why this is the case?

[Matt J]

Where were you running it before? In any case, there was clearly something in your environment interfering. Maybe a variable named 'fit'? Try clearing your workspace and redoing whatever it is you did originally.

[Wenlin]

I was running it just as a script before. I tried clearing the workspace or restarting from a blank instance a few times before but that didn't solve it either. It seems to be working fine now but still not sure what have caused it.

Answer 2

[Image Analyst]

What does this show

size([x, y])
size(z)

Don't use a semicolon and tell us what it says the sizes are in the command window.

[Wenlin]

Here's the output:

ans =

293     2


ans =

293     1