Hi Ondrej,
To avoid the repeated initialization of your Python function within the Simulink model, you can use persistent variables in your MATLAB Function block to store the function handle across function calls. The persistent variable will be initialized only once when the model starts running. Refer to the documentation below to read more about it:
You can modify your MATLAB Function block as shown below:
function y = fcn(t,u)
y = [0;0];
coder.extrinsic('py.Pyfun.create_symbolic_expression')
coder.extrinsic('py.Pyfun.lambdify_expression')
persistent myfunc
if isempty(myfunc)
expr = py.Pyfun.create_symbolic_expression();
myfunc = py.Pyfun.lambdify_expression(expr);
end
y = double(myfunc(t,u(1),u(2)));
end
In the code above, 'myfunc' is declared as a persistent variable, which means that its value is retained in memory between calls to the function. The check 'isempty(myfunc)' ensures that the Python function is only created and lambdified once, when 'myfunc' is not yet initialized (i.e., during the first function call).
The InitFcn callback in the model's Callbacks is not suitable for initializing variables used within the MATLAB Function block because the scope of variables defined in the InitFcn is not shared with the MATLAB Function block.
