How to feed the output of a user defined embedded function back into one of the inputs?

Hi,

I would like to feed back one of the outputs of my user defined embedded function (Matlab Function block) back into one of the inputs (of the same function block) during the next iterative cycle.

May I know how can this be done? Thanks alot for helping!

Answer 1

[Kaustubha Govind]

Connecting an output back as an input will cause algebraic loops, so you may see errors or warnings from the Simulink solver when you do this. The best thing might be to maintain an internal state to save the previous output and use in the next time-step. For example:

function y = mytest(u)
%#codegen
persistent prev_y; %internal state
if isempty(prev_y)
   prev_y = 0; %initial value
end
y = 2*u + prev_y;
prev_y = y;

Answer 2

[Bassam Saleh]

using a memory block beyond the o/p signal and in-front of the i/p signal will solve this issue.