When I try to run this code...it showing error message 'Undefined function 'FDE_PI1_Un' for input arguments of type 'function_handle'. Please help me in it.

alpha=[0.67];
Lambda=400;beta=0.000017;lambda(1)=0.0002;lambda(2)=0.002;r(1)=0.16979;
r(2)=0.16979;alph(1)=0.03275;alph(2)=0.03275;d=0.0096;theta(1)=0.2;
theta(2)=0.02;u=0.0005;phi=0.06;
param=[Lambda,beta,lambda(1),lambda(2),r(1),r(2),alph(1),alph(2),d,theta(1),theta(2),u,phi];
f_fun=@(t,y,par)[
par(1)^alpha - y(1)*y(3)*par(2)^alpha - y(1)*y(5)*par(3)^alpha - y(1)*par(9)^alpha + y(3)*par(5)^alpha + y(4)*par(6)^alpha + y(2)*par(10)^alpha;
y(1)*y(5)*par(3)^alpha - y(2)*par(9)^alpha - y(2)*par(10)^alpha;
y(1)*y(3)*par(2)^alpha - y(3)*par(5)^alpha - y(3)*par(8)^alpha + y(3)*y(5)*par(4)^alpha + y(4)*par(11)^alpha;
y(3)*y(5)*par(4)^alpha - y(4)*par(9)^alpha - y(4)*par(11)^alpha - y(4)*par(6)^alpha - y(4)*par(8)^alpha;
y(3)*par(12)^alpha - y(5)*par(13)^alpha];

J_fun=@(t,y,par)[-par(2)^alpha*y(3) - par(3)^alpha*y(5) - par(9)^alpha , par(3)^alpha*y(5), par(2)^alpha*y(3),0,0;
    par(10)^alpha,-par(9)^alpha-par(10)^alpha,0,0,0;
    -par(2)^alpha*y(1)+par(5)^alpha,0,par(2)^alpha*y(1)-par(5)^alpha-par(7)^alpha-par(9)^alpha+par(4)^alpha*y(5),par(4)^alpha*y(5),par(1)^alpha*y(3);
    0,0,0,-par(9)^alpha-par(11)^alpha-par(6)^alpha-par(8)^alpha,0;
    -par(3)^alpha*y(1),par(3)^alpha*y(1),par(4)^alpha*y(5),par(4)^alpha*y(5),-par(13)^alpha];
t0=0;T=200;
y0=[900;300;300;497;200];
h=2^(-8);
%%%%%%%%%%%%%%%%%%%%%%%%%%
[t, y] = FDE_PI1_Un(alpha,f_fun,t0,T,y0,h,param) ; 
figure(1) 
plot(t,y(1,:)) ; 
xlabel('t') ; ylabel('S(t)') ; 
%legend('x(t)') ; 
%title('PI1'); 

[Walter Roberson]

FDE_PI1_Un is not a Mathworks supplied function. We as outside observers have no reason to expect that it would be defined anywhere.

[Zeit]

Even, I changed to '[t, y] = FDE_PI1_Ex(alpha,f_fun,t0,T,y0,h,param) ;'. It still not working.

In another example this code is working but when I use it in my example it shows error.

[Zeit]

alpha=[0.67];         order of derivative
Lambda=400;beta=0.000017;lambda1=0.0002;lambda2=0.002;r1=0.16979;            parameters
r2=0.16979;alph1=0.03275;alph2=0.03275;d=0.0096;theta1=0.2;
theta2=0.02;u=0.0005;phi=0.06;
param=[Lambda,beta,lambda1,lambda2,r1,r2,alph1,alph2,d,theta1,theta2,u,phi];
f_fun=@(t,y,par)[                                                                                   function definition
par(1)^alpha - y(1)*y(3)*par(2)^alpha - y(1)*y(5)*par(3)^alpha - y(1)*par(9)^alpha + y(3)*par(5)^alpha + y(4)*par(6)^alpha + y(2)*par(10)^alpha;
y(1)*y(5)*par(3)^alpha - y(2)*par(9)^alpha - y(2)*par(10)^alpha;
y(1)*y(3)*par(2)^alpha - y(3)*par(5)^alpha - y(3)*par(8)^alpha + y(3)*y(5)*par(4)^alpha + y(4)*par(11)^alpha;
y(3)*y(5)*par(4)^alpha - y(4)*par(9)^alpha - y(4)*par(11)^alpha - y(4)*par(6)^alpha - y(4)*par(8)^alpha;
y(3)*par(12)^alpha - y(5)*par(13)^alpha];

J_fun=@(t,y,par)[-par(2)^alpha*y(3) - par(3)^alpha*y(5) - par(9)^alpha , par(3)^alpha*y(5), par(2)^alpha*y(3),0,0;
    par(10)^alpha,-par(9)^alpha-par(10)^alpha,0,0,0;
    -par(2)^alpha*y(1)+par(5)^alpha,0,par(2)^alpha*y(1)-par(5)^alpha-par(7)^alpha-par(9)^alpha+par(4)^alpha*y(5),par(4)^alpha*y(5),par(1)^alpha*y(3);
    0,0,0,-par(9)^alpha-par(11)^alpha-par(6)^alpha-par(8)^alpha,0;
    -par(3)^alpha*y(1),par(3)^alpha*y(1),par(4)^alpha*y(5),par(4)^alpha*y(5),-par(13)^alpha];
t0=0;T=50;                                   
y0=[1.2;2.8;1.2;2.8;1.2;2.8];
h=2^(-6);

%%%%%%%%%%%%%%%%%%%%%%%%%%
[t, y] = FDE_PI1_Ex(alpha,f_fun,t0,T,y0,h,param) ;
figure(1) 
plot(t,y(1,:)) ; 
xlabel('t') ; ylabel('S(t)') ; 
%legend('x(t)') ; 
%title('PI1'); 
%%%%%%%%%%%%%%%%%%%%%%%%%%

It still shows error in '[t, y] = FDE_PI1_Ex(alpha,f_fun,t0,T,y0,h,param) '.

[Walter Roberson]

As outside observers, we have no reason to expect that function to exist either.

That function name happens to match a function mentioned at https://galileo.dm.uniba.it/Members/garrappa/Software . That page is old and does not have current security so your browser might not be willing to display it. That particular function leads to the dropbox link https://www.dropbox.com/s/c0ai2brgynxkmbz/FDE_PI1_Ex.m?dl=0