MATLAB: Hi, what should I do to get the ‘Not enough input arguments’-error,

errornarginchknot enough input arguementsvargin

If I call my own function with not enough input arguments MATLAB realizes this not until the missing variable is used.
Example:
function d = inputErrorCheck(a,b,c)
if a > b 
    d = a+b;
else
    d = a+c;
end;    
end
Output:
>> inputErrorCheck(3,2)
ans = 5
>> inputErrorCheck(2,3)
Not enough input arguments.
Error in inputErrorCheck (line 6) d = a+c;
Is there a setting or something to get MATLAB to check the amount of input arguments before it starts the function?
Thanks!

Best Answer

Hi Rebecca,
your problem seems to be closely related to the question of strict data typing for function arguments in Matlab. As far as I know, you cannot do it automatically in Matlab. Matlab functions usually start with checking the number and data type of the input arguments manually, see e.g. gaussmf from the statistics toolbox with 7 lines of checking input arguments and 2 lines of actual code (R2014b).
There are several ways of checking the input arguments:
  • Using nargin (or narginchk), is* and error. Check the Fundamental MATLAB Classes to get a feeling of the checks you need to perform.
  • Using the validateattributes function.
  • Using the inputParser class.
  • Using try catch
  • Compile it as a mex-function. You will need to specify the datatypes before compiling.
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