How to access class and functions from python

Hello All,

I am trying to access matlab code in python. I have referred ref1 and ref2 I am able to work with single function code, but not with a multi function code as mentioned in ref2 or even this basic example

        classdef Test1
            properties (Access = private)
                input1 = 0;
                input2 = 0;
            end

            methods

                function out1 = ADD_1(this,i1,i2)

                    this.input1 = i1;
                    this.input2 = i2;
                    out1 = this.input1 + this.input2;

                end
                function out2 = SUB_1(this,out1)
                    out2 = out1 - 1;
                end

            end
        end

What I have tried is

import matlab.engine
eng = matlab.engine.start_matlab()
eng.addpath(r'C:\Users\Python_file_test', nargout=0);
func1_out = eng.ADD_1(10,20)

I get an error

MatlabExecutionError: Undefined function 'ADD_1' for input arguments of type 'int64'.

Answer 1

[Siddharth Bhutiya]

Whenever you create a class in MATLAB it will be a Value class by default. However, while working with MATLAB Engine for python you can only use MATLAB Handle classes, which is mentioned in the link below

https://www.mathworks.com/help/matlab/matlab_external/handle-data-returned-from-matlab-to-python.html

So in order to make the above example work, you will have to make your class a handle class which can be done by replacing the first line of your MATLAB code to

classdef Test1 < handle

Another thing to note here is that the function signature of ADD_1 indicates that it needs 3 inputs: Test1 Object(this), first number(i1) and second number(i2). So inside your python script, you will have to create an object for Test1 and pass it as the first argument of ADD_1

 myobj = eng.Test1()
 func1_out = end.ADD_1(myobj, 10, 20)

I believe that the above changes should resolve your issue.

[Arshad Pasha]

Hey Siddhart, thank you, that worked. Just a follow up question, how to handle the recursive functions, let's say a function is called every 1 second in matlab, can I monitor that or call that via python similar to what you have suggested previously. just to simplify, want to call the ADD_1 function 10 times in a loop via python.

classdef Test1 < handle
    properties (Access = private)
        input1 =0;
        input2 = 0;
    end

      methods

          function out1 = ADD_1(this,i1,i2)

              this.input1 = i1;
              this.input2 = i2;
              out1 = this.input1 + this.input2;

          end

          function out2 = SUB_1(this,out1)
              out2 = out1 - 1;
          end

      end
  end