matlab程序崩溃怎么解决,跪求matlab达人帮我看看程序，我实在是要崩溃了......

程序报错：Output returned by S-function 'controller' in

'untitled/S-Function' during flag=3 call must be a real vector of

length 1.

程序如下：

function[sys,x0,str,ts]=controller(t,x,u,flag)

switch flag,

case

0,

[sys,x0,str,ts]=mdlInitializeSizes;

case

1,

sys=mdlDerivatives(t,x,u);

% outputs

case

3,

sys=mdlOutputs(t,x,u);

%unhandled flags

case{2,4,9}

sys=[];

%unexpected flags

otherwise

error(['Unhandled flag =',num2str(flag)]);

end

%mdlinitializesizes

function[sys,x0,str,ts]=mdlInitializeSizes

sizes = simsizes;

sizes.NumContStates = 3;

sizes.NumDiscStates = 0;

sizes.NumOutputs = 1;

sizes.NumInputs = 3;

size.D