I'm pretty new using Matlab, im not sure why there's an error at line number 2. It says( Error in ==> Asys at 3 switch flag,;). I'm not sure why this error occurring. Thanks in advance. Syah.

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

switch flag,;

      case 0

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

      case 3

          sys = mdlOutputs(t,x,u);

      case{1,2,4,9}

          sys = [];

      otherwise

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

end

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

sizes = simsizes;

sizes.NumContStates = 0;

sizes.NumDiscStates = 0;

sizes.NumOutputs = 3;

sizes.NumInputs = 5;

sizes.DirFeedthrough = 1;

sizes.NumSampleTimes = 1;

sys = simsizes (sizes);

str = [];

x0 = [];

ts = [-1 0];

function sys = mdlOutputs (t,x,u)

P = sys(3) - sys(4);

if (sys(5) >= 0.3);

      if (sys(4) >= sys(3))

          u(1) = 0;
          u(2) = sys(4);
          u(3) = 0;

      else

          if ((sys(2) >= 0.3));

              if (sys(1) >= sys(3))
                  u(1) = P;
                  u(2) = sys(4);
                  u(3) = 0;

              else
                 u(1) = 0;
                 u(2) = 0;
                 u(3) = sys(3);
              end

          else
              u(1) = 0;
              u(2) = 0;
              u(3) = sys(3);
          end

      end

else
   u(1) = 0;

     u(2) = 0;

     u(3) = sys(3);

end

sys = u;

[Artur M. G. Lourenço]

del "," in "switch flag,;"

Answer 1

[Image Analyst]

Why is there a comma and semi colon after the switch? Get rid of them.

[Artur M. G. Lourenço]

in your post, you put "," before switch. works now?

[Syah]

I've tried to delete 1) " , " still got error. 2) " ,; " also got error.

[Image Analyst]

Why do you think there should be anything after the switch. Just have switch and no punctuation marks whatsoever after it.

[Syah]

i've done what u suggested, but still error occurring.

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

switch flag

      case 0
          [sys,x0,str,ts] = mdlInitializeSizes;
      case 3
          sys = mdlOutputs(t,x,u);
      case{1,2,4,9}
          sys = [];
      otherwise
          error(['Unhandled flag = ', num2str(flag)]);
end

[Image Analyst]

It can't. It can't say "Error in ==> Asys at 3 switch flag,;" because you don't have the comma and semi colon anymore. What does it really say? Give the whole error message - all the red text. You're not even giving the actual error message - it never just says "Error in..." without giving a reason for the error.

[Syah]

i forgot to mention the complete error. it says:

Input argument "flag" is undefined.

Error in ==> Asys at 3

switch flag

help me with this one, i don't understand. what does it mean?

[Walter Roberson]

How are you executing the code? If you are selecting Run from the menu or pressing the Run button, then that will execute the code with no parameters. You need to call the code from other code, or you need to call it from the command line with appropriate parameters defined. The code is designed to be called from Simulink; is that how you are executing it?

[Abioye Samson]

call the function in a script m file instead of running it directly and supply the actual values of the input parameters

e.g

 [sys,x0,str,ts] = Asys (10,2,4,3)
i.e
 t=10,x=2,u=4,flag=3