log plot in matlab

Hello,

I am trying to plot a log function.

So , i first calculate the integral of a function.

Second, make a simpson approximation,

Third , calculate the error between the integral and each approximation from n = 2 to n= 100000;

And fourth I try to plot a log graph having the x axis : n from 2 to 100000 , and its corresponding error on the y axis... However, the graph its not plotting any results, can anyone please help me out with this?

1)

function [I] = actualintegral(x)

fun = @(x) exp(-x.^2);

xmin=0;

xmax=1;

I= integral(fun,xmin,xmax);

end

...

2)

function[S] = simpson(n)

f=@ (x)exp(-x^2);

a= 0 ;

b= 1;

h = (b-a)/n;

g = f(a)+f(b);

for i = 1:2:n-1

g=g+4*f(a+i*h);

end

for i= 2:2:n-2

g= g+2*f(a+i*h);

end

S =h/3 * g;

end

...

3)

function [error] = errort(I,S,n)

I = actualintegral();

for n=2:100:100000

S = simpson (n);

error = abs(I - S)

end

end

...

4)

function [P] = logplot(I,S,n)

x = logspace(0,4);

y = errort ();

loglog(x,y,'-s')

grid on

end