ekf matlab switch flag error

hello every body i have to build an ekf model for PMSM motor so searched and found this code

function [sys,x0,str,ts]=EKM6a(t,x,u,flag,P,Q,R);
%global Rs Ld Lq Fm v_alpha v_beta i_alpha i_beta;
%global P Q R fid;
%global out fit;
Rs=5;
Ld=10e-3;
Lq=10e-3;
Fm=0.175;
T=5e-4;
%i=0;
Bd=[1/Ld 0;0 1/Lq;0 0;0 0];
H=[1 0 0 0;0 1 0 0];
switch flag
case 0
%ekmini;
sizes=simsizes;
sizes.NumContStates=0;
sizes.NumDiscStates=4;
sizes.NumOutputs=4;
sizes.NumInputs=4;
sizes.DirFeedthrough=0;
sizes.NumSampleTimes=1;
str=[];
ts=[0.0005 0];
x0=[0; 0; 0; 0];
sys = simsizes(sizes);
case 2
% Step 1:Initialization of the state vector and covariance matrices
Uk=[u(1);u(2)];
Y=[u(3);u(4)];
% Step 2:Prediction of the state vector
fx=[-Rs/Ld*x(1)+Fm/Ld*x(3)*sin(x(4)) ;-Rs/Lq*x(2)-Fm/Lq*x(3)*cos(x(4)) ;0 ;x(3) ];
F=[-Rs/Ld 0 Fm/Ld*sin(x(4)) Fm/Ld*x(3)*cos(x(4));0 -Rs/Lq -Fm/Lq*cos(x(4)) Fm/Lq*x(3)*sin(x(4));0 0 0 0;0 0 1 0];
x1=x+T*(fx+Bd*Uk);
% Step 3: Covariance estimation of prediction
P1=P+T*(F*P+P*F')+Q; % P1 is 4x4
% Step 4: Kalman filter gain computation
K1=P1*H'*inv(H*P1*H'+R);% K1 is 4x2
% Step 5: State vector estimation
h=[x1(1);x1(2)];
sys=x1+K1*(Y-h);
% Step 6: Covariance matrix of estimation error
P=P1-K1*H*P1;
case 3
sys=x;
case 4
sys=(round(t/T)+1)*T;
%sys=[];
case 9
sys=[];
end

    if true
      % code
    end
the problem is when i run the code it's gave me the error below:

EKM6a
Not enough input arguments.

Error in EKM6a (line 14)
switch flag
i dont know how to solve this problem please help me

[Ge Zhang]

I have the same 'Not enough input' problem, did you find the way to fix it?

[jessupj]

you don't run the code. it's a function, so you have to CALL the function by passing it arguments.