# Undefined function 'geomean' for input arguments of type 'double' in Matlab 2020

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Adi Purwandana on 4 Mar 2023
Commented: Walter Roberson on 5 Mar 2023
Dear all,
I have a simple code containing "geomean" for a data with nan values. I tried this code:
geomean(X,'omitnan')
in Matlab 2022 and it runs well. But, when I tried in Matlab 2021, I got this message:
Undefined function 'geomean' for input arguments of type 'double'.
I also tried a classical way:
geomean(X(~isnan(X)));
And it gives me the same problem.
Any suggestion regarding this error?

Steven Lord on 4 Mar 2023
The geomean function is part of Statistics and Machine Learning Toolbox. Do you have this toolbox installed and licensed? You can check this by running the ver command and looking for a line starting with "Statistics and Machine Learning Toolbox" in the displayed output.
If that line does not exist you will need to install Statistics and Machine Learning Toolbox to use this function.

Star Strider on 4 Mar 2023
An alternative is:
gm = @(x) prod(x)^(1/numel(x));
x = rand(1,100);
y1 = geomean(x)
y1 = 0.3765
y2 = gm(x)
y2 = 0.3765
.
Walter Roberson on 5 Mar 2023
The anonymous function gm is not designed to be a complete drop-in replacement for all functionality of geomean. Star Strider and I made no attempt to handle omitnan or the dimension arguments, and did not pay attention to calculations on matrices.
We also were not telling you that gm or gmL were already available in your version of MATLAB: we were providing a quick fix.
If you need more functionality then you should define your own gm.m using the mathematical logic we show, but perhaps looping over each column removing nan values before doing the calculation.

Walter Roberson on 4 Mar 2023
it needs the Statistics and Machine Learning toolbox
##### 2 CommentsShow 1 older commentHide 1 older comment
Walter Roberson on 5 Mar 2023
Edited: Walter Roberson on 5 Mar 2023
The software needs to be licensed and installed on whatever MATLAB you are executing the code with.

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