Lowess smoothing disappears in Curve Fitting App

I want to perform a demonstration to students on how the LOWESS filter works, using the Curve Fitting App. But as soon as I select any x or y data series, the Lowess option vanishes from the menu of possible fit functions ! I have tried all possible combination or sequence of commands I could think of, and tried both on my desktop version and on MATLAB online, same result. I can't figure out why I am doing wrong. Could not find any answers in MATLAB documentation, or on user forums. Any clues ?

Answer 1

[Steven Lord]

According to this documentation page lowess is supported for surface fitting, not curve fitting. So if you specify x, y, AND z data you should be able to select lowess as the fitting method.

[Christian Zdanowicz]

That explains it. I missed that. Thanks.

Answer 2

[Bjorn Gustavsson]

I suggest you scrap the curve-fitting app, the way to go is to start from Loren's nice blogg-post on LOWESS-fitting. That way every step along the way gets properly presented to your students, in a way that are really (at least very reasonably) traceable, that the app kind of hides away.

HTH

[Christian Zdanowicz]

Regardless, I'd like to know what the issue is, i.e., is there a bug in the app or not.

[Bjorn Gustavsson]

Fair point. Will take a look, can you share the data that you get the problem with, or should we just make up something with any size?

[Christian Zdanowicz]

Does not seem to depend on data. I get this problem with any randomly-generated X and Y data.