Undefined function or variable 'inputParser' while using Matlab Function in Stateflow

Hello all,

I'm using a matlab function within my stateflow diagram, however I'm getting the error "Undefined function or variable 'inputParser'". When I try to run the function within a .m file it works fine. I cannot find any limitations to inputParser usage in stateflow within the help files or by google.

Code:

function x = OK(i) 
    default = 1:50; 
    p = inputParser; 
    addOptional(p,'i',default);
    parse(p,i);

    if all(Input_Mux(i)== enumState.OK)
         x = true;
    else
         x = false;
    end
end

Does anyone know why this is failing?

[Ameer Hamza]

In this function, the result of parse() is not being used. Why not remove those lines?

[Christian Black]

Hello Ameer, thanks for your feedback. Yes the above didn't match my intention, sorry I'm new to using the inputParser class. I've now corrected the code to reference the parsed input, but I'm still getting this error when the function is used within stateflow.

function x = OK(varargin) 

    Input_mux = [1:100]; %Would normally be stateflow input, added here for ease.
    
    default = 1:50; 
    p = inputParser; 
    addOptional(p,'i',default);
    parse(p,varargin{:});
    if all(Input_mux(p.Results.i)== 5)
         x = true;
    else
         x = false;
    end
end

[Ameer Hamza]

It seems that the problem might be happening because the inputParser does not support code generation. You may try coder.extrinsic

coder.extrinsic('inputParser', 'addOptional', 'parse')

add this line at beginning of function definition

function x = OK(varargin)
    coder.extrinsic('inputParser', 'addOptional', 'parse')
    Input_mux = [1:100]; %Would normally be stateflow input, added here for ease.
    
    default = 1:50; 
    p = inputParser; 
    addOptional(p,'i',default);
    parse(p,varargin{:});
    if all(Input_mux(p.Results.i)== 5)
         x = true;
    else
         x = false;
    end
end

[Christian Black]

Thanks Ameer, that is just what I needed. I also found that you could not directly extract the 'Results' feild as you receive an 'mxArray' error so you need to use the get method with a preintialised varible:

function x = OK(varargin)
    coder.extrinsic('inputParser', 'addOptional', 'parse', 'get')
    Input_mux = [1:100]; %Would normally be stateflow input, added here for ease.
    
    default = 1:50; 
    p = inputParser; 
    addOptional(p,'i',default);
    parse(p,varargin{:});
    
    temp = [0];
    temp = get(p,'Results.i')
    
    if all(Input_mux(temp)== 5)
         x = true;
    else
         x = false;
    end
end

Thanks again for your help!

P.S Ameer, if you move your above comment to an awnser that I'll accept it. I do not currently have the option.

[Ameer Hamza]

Good that this solution worked. I have added this as an answer with modification to make it work. Thanks.

[Christian Black]

Update for anyone else who finds this post:

The above solution works well to run Simulink natively, however if you wish to use code generation for either running on dedicated hardware or for using reference models in a large simulink model you are unable to do so as the coder is unable to parse extrinsic functions.

Answer 1

[Ameer Hamza]

It seems that the problem might be happening because the inputParser does not support code generation. You may try coder.extrinsic

coder.extrinsic('inputParser', 'addOptional', 'parse', 'get')

add this line at beginning of function definition

function x = OK(varargin)
    coder.extrinsic('inputParser', 'addOptional', 'parse', 'get')
    Input_mux = [1:100]; %Would normally be stateflow input, added here for ease.
    
    default = 1:50; 
    p = inputParser; 
    addOptional(p,'i',default);
    parse(p,varargin{:});
    if all(Input_mux(p.Results.i)== 5)
         x = true;
    else
         x = false;
    end
end

'get' is needed as extrensic to extract data from p.Results as shown in comment: https://www.mathworks.com/matlabcentral/answers/542015-undefined-function-or-variable-inputparser-while-using-matlab-function-in-stateflow#comment_884843