Matlab S函数错误

Question

我正在尝试使用Matlab S-Function构建跟踪器微分器。但是，它给了我一个错误说＆＃34; 输出由S-function＆＃39; han_td＆＃39; in＆＃39; ex_han / S-Function＆＃39;在flag = 3期间，call必须是长度为2的实数向量＆＃34;。

我无法看清我做错了什么。以下是代码：

function [sys,x0,str,ts]=han_td(t,x,u,flag,r,h,T)           
switch flag,
    case 0, [sys,x0,str,ts]=mdlInitializeSizes(T);          
    case 2, sys = mdlUpdates(x,u,r,h,T);                    
    case 3, sys = x;                          
    case {1, 4, 9}, sys = [];                               
    otherwise, error(['Unhandled flag = ',num2str(flag)]);  
end;

%initialization function mdlInitializeSizes
function [sys,x0,str,ts] = mdlInitializeSizes(T)    
sizes = simsizes;                       
sizes.NumContStates = 0;                
sizes.NumDiscStates = 2;                
sizes.NumOutputs = 2;                   
sizes.NumInputs = 1;                    
sizes.DirFeedthrough = 0;               
sizes.NumSampleTimes = 1;               
sys = simsizes(sizes);                  
x0 = [0;0];                            
str = [];                             
ts = [-1 0]; 


function sys = mdlUpdates(x,u,r,h,T)    
sys=[x(1)+T*x(2); x(2)+T*fst2(x,u,r,h)];

function f=fst2(x,u,r,h)
delta =r*h;
delta0=delta*h;
y0=x(1)-u+h*x(2);
a0=sqrt(delta*delta+8*r*abs(y0));
if abs(y0)<=delta0, a=x(2)+y0/h;
else, a=x(2)+0.5*(a0-delta)*sign(y0);  end
if abs(a)<=delta, f=-r*a/delta;
else, f=-r*sign(a);end