persistent variable simulink codegen stateflow error: "IR Construction failed"

Greetings,

I'd like to include a function similar to the following in my codegen-compiled simulink model:

function u = PD_control( x )

    persistent x_last_iter            % save last x each iter
    if isempty(x_last_iter)
        x_last_iter = x;              % 1st iter -> set to 1st x
    end
    
    Kp = 1;    Kd = 1;                % PD control params
    u = -x*Kp + (x_last_iter - x)*Kd  % calculate control input
end

However, I get compiler error below. "IR Construction failed" returns zero hits when I search the web.

I can avoid this error by setting the initial value to 0 instead: "x_last_iter = 0;" But this is not ideal.

Anyone understand this error? I feel I am correctly following the documentation here: Persistent Variables and Persistent Array Variables

Respectfully, John

Answer 1

[Fangjun Jiang]

I think IR means "Internal Representation". It might be a bug. Make a simple example and submit a service request to the Mathworks.