how to define x-vectorm in M S-Function

Hi a question

i cant understand how defined x-vector in m s-function (in simulink loop) ... and what process done on input in my sample m s-function code. input is a step function.my sample code is below

help please

function [sys,x0] =FT_Ball(t,x,u,flag)

%global kb

kb=12;

switch flag

case 1

    sys(1)=3*x(2);
    sys(2)=x(3);
    sys(3)=(kb^3*u- 5*kb*x(3) - 6*kb^2*x(2)-kb^3*x(1));

case 3

    sys(1)=x(1);

case 0

    sys=[3,0,1,1,0,0];
    x0=[0,0,0];

case {2,4,9} sys=[];

end

Answer 1

[Kaustubha Govind]

You are required to return your computed states (the vector x) in Case 2 (mdlUpdate). Please read Maintain Level-1 MATLAB S-Functions for information on how each Case (method) is executed.

Also, it is highly recommended that you write a Level-2 MATLAB S-function instead of Level-1 (which is what you're writing) when creating a new S-function. The Level-1 interface was deprecated several releases ago and may not be supported in future releases of Simulink.