Undefined function or variable 'lgamma'.

Question

NMarco 2021-1-25

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https://ww2.mathworks.cn/matlabcentral/answers/726733-undefined-function-or-variable-lgamma

评论： Walter Roberson 2021-2-8

采纳的回答： Walter Roberson

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Hello experts,

as the title says I have a problem with this undefined 'lgamma'.

I'm trying to run an ANCOVA using the function aoctool() but it stops and throws me that error.

Below I post the entire message:

Undefined function or variable 'lgamma'.
Error in betapdf (line 60)
                  + lgamma (a + b) - lgamma (a) - lgamma (b));
Error in betainv (line 87)
    h     = (betacdf (y_old, a, b) - x) ./ betapdf (y_old, a, b);
Error in finv (line 58)
  inv(k) = ((1 ./ betainv (1 - x(k), n/2, m/2) - 1) * n / m);
Error in aoctool>getyvalues (line 777)
      crit = sqrt(df1 * finv(1-alpha/bonf, df1, df2));
Error in aoctool (line 335)
        [newy, ~, ycov] = getyvalues(allx, allgrps, model, stats, ud);
 

I'm working on MATLAB R2018b.

Is this related with a MATLAB issue or (most likely) it's just me erroneously defining the ANCOVA variables?

Thank you for your help!

Marco

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Star Strider 2021-1-26

You need to Contact Support .

I opened betapdf.m in the MATLAB editor, and the last line of the function is 58. That line contains a betaln call, and there are no gamma function calls of any kind in the entire function. (I am using R2020b.)

NMarco 2021-1-26

@Adam Danz , @Star Strider thank you for your feedback.

The lgamma is from a internal MATLAB code, that's why I'm concerned about this error.

I will contact the support, I guess..

Thanks anyway!

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Answer 1

Walter Roberson 2021-1-26

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/726733-undefined-function-or-variable-lgamma#answer_606323

I see relevant discussion at https://github.com/wichmann-lab/psignifit/issues/4 . The implications there are that you are picking up a third-party toolbox version of finv that is invoking a third-party betainv that is invoking a third-party betapdf that is asking for lgamma that has not been part of MATLAB for a number of years.

The fix would be to move those that third-party finv (and related) out of your MATLAB path.

By the way, the Mathworks long gamma function is gammaln() these days, and is part of basic MATLAB.