I am trying to solve a second order ODE using Finite difference method.I have written a code as below but it shows error upon running.Can anyone help me find the potential error in my code.Thanks

function [x,U]=FD(a,b,ua,uxb,f,n)

a=0;b=10;n=100;

h=(b-a)/n;

h1=h*h;

A=sparse(n-1,n-1);

F=zeros(n-1,1);

for i=1:n-2

A(i,i)=-2/h1;A(i+1,i)=1/h1;A(i,i+1)=1/h1;

end

 A(n-1,n-1)=-2/h1;

for i=1:n-1

x(i)=a+i*h;

f=0.091875*cos(x(i));

F(i)=feval(f,x(i));

end

F(1)=F(1)-ua/h1;

F(n-1)=F(n-1)-uxb/hi;

U=A/F;

a=0;b=10;n=100;

ua=0;uxb=0;

[x,U]=FD(a,b,ua,uxb,'f',n);

plot(x,U,0);hold

u=zeros(n-1,1);

for i=1:n-1,

u(i)=0.091875*cos(x(i));

end

plot(x,u)

The error shown to be as ;

Error using feval

Argument must contain a string or function_handle.

Error in FD (line 14)

F(i)=feval(f,x(i));

Answer 1

[Torsten]

f=@(x)0.091875*cos(x);

F(i)=feval(f,x(i));

Best wishes

Torsten.

[Richardson Joseph]

Hi,

It shows me this error

Error using FD (line 16) Not enough input arguments.(for the below line)

"F(1)=F(1)-ua/h1"

Thanks

[Richardson Joseph]

I tried it again,It showing a error something like,

Maximum recursion limit of 500 reached. Use set(0,'RecursionLimit',N) to change the limit. Be aware that exceeding your available stack space can crash MATLAB and/or your computer.

Thanks

[Torsten]

Save the function FD in a separate script. Otherwise, you call FD recursively with the call

[x,U]=FD(a,b,ua,uxb,'f',n);

at the end of the program.

Best wishes

Torsten.