s-function error

Hello i have a problem with my s-function

i have this error after run my simulink

'smtest/S-function'while executing M-File S-function 's-function',flag=0(initialize),at start of simulation.MATLAB error message:Undefined function or variable 'mdllnitializes' this is the function

function [sys,x0,str,ts]=s_function(t,x,u,flag)
  switch flag,
      case 0,
          [sys,x0,str,ts]=mdlInitializes;
      case 1,
          sys=mdlDerivatives(t,x,u);
      case {2,4,9}
          sys=[];
      otherwise
          error(['Unhandled flag=',num2str(flag)]);
  end

    function [sys,x0,str,ts]=mdlInitializeSizes
    sizes=simsizes;
    sizes.NumContStates=2;
    sizes.NumDiscStates=0;
    sizes.NumOutputs=2;
    sizes.NumInputs=1;
    sizes.DirFeedthrough=0;
    sizes.NumSampleTimes=0;
    sys=simsizes(sizes);
    x0=[0.5 1.0];
    str=[];
    ts=[];

    function sys=mdlDerivatives(x,u)
    J=10;
    sys(1)=x(2);
    sys(2)=1/J*u;

    function sys=mdlOutputs(x,u,t)
    sys(1)=x(1);
    sys(1)=x(2);

Answer 1

[Les Beckham]

Replace mdlInitializes with mdlInitializeSizes