curious behavior of geomean

I'm using matlab 2017a.

I've been having some trouble getting the expected output from geomean.

In debugging this, per the geomean documentation here https://www.mathworks.com/help/stats/geomean.html

i tried to run the following code

x = 1:10;

x(3) = nan; % Replace the third element of x with a NaN value

n = geomean(x,'omitnan')

And the expected response as mentioned in the documentation is n = 4.7408

In contrast, i get back

Error using size

Dimension argument must be a positive integer scalar within indexing range.

Error in geomean (line 26)

n = size(x,dim);

This seems like a pretty foundational problem if even this simple code example from the documentation is generating an error.

Any thoughts as to what might be going on here?

Answer 1

[John D'Errico]

As is always the case, consider what MATLAB release you are using.

x = 1:10;
x(3) = nan; % Replace the third element of x with a NaN value
n = geomean(x,'omitnan')

n = 4.7408

As you can see, when run using a current release, it works fine. The documentation you reference is for the CURRENT release (which would be R2020b), but you say you are using R2017a.

Things change. Options get added in newer releases. You can't always assume backwards compatibility for all new releases.

[Kristopher Dawsey]

Thanks a lot for the response, John. Yes i think you're exactly right. The backward compatible version i suppose would just be the below. Sorry I should have thought of that as a likely explanation. Thanks again.

>> n = geomean(x(~isnan(x)))

n =

4.7408

Answer 2

[Steven Lord]

According to the Release Notes the ability to specify 'omitnan' to omit NaN values from the geometric mean calculations in geomean was introduced in release R2019a.