Calling Python function with multiple outputs in Simulink

Hello everyone,

I'm trying to call a function from a python script with matlab function block in simulink.

The problem is that the python function returns two variables and I can't read these variables in simulink.

Python function :

def test(x, y):
    dr_x = x + x*y
    dr_y = y + x/y  
    return dr_x, dr_y

And I call this function with a matlab function block in simulink:

function  [dr_x, dr_y] = testQuest(x, y) % Matlab function block code

coder.extrinsic("pyversion")
coder.extrinsic("py.list")
coder.extrinsic("py.tuple")

pyversion;
    dr = py.tuple({0,0}); % intialisation
    dr_x = 0; % intialisation
    dr_y = 0; % intialisation
    
    coder.extrinsic('py.testQ.test') 
    
    dr = py.testQ.test(x,y); 
    
    dr_c = cell(dr);
    dr_x = dr_c(1);
    dr_y = dr_c(2);

When I run it, I receive an error saying: MATLAB expression 'py.testQ.test' is not numeric.

I tried different ways such as:

    [dr_x, dr_y] = py.testQ.test(x,y);

instead of:

    dr = py.testQ.test(x,y);

But all gives me different errors about the type of the output.

I wonder if it's possible to get multiple outputs from the python function in simulink.

Thank you !

Answer 1

[Yongjian Feng]

Which version of matlab and python are you using?

I tested 2021a, and calling py.testQ.test(x, y) returns a Python tuple.

ret = py.testQ.test(x, y);
ret{1}
ret{2}

[Dino]

Hello, thank you for the answer, I'm using Matlab 2018b.

Yes, on Matlab there's no problem returning tuple, however if I call the same function on simulink with matlab function block, it doesn't work. I cannot take two variables as output from one python function. So now I'm using interpreted matlab function block to call the function with .m file. It works in this way.