Scilab Program - simpsons 3/8 rule - IProgramX

Program

function[]=simp3(x,f)
    [x0,xn]=size(x)
    [y0,yn]=size(f)
    if((x0<>1)|(y0<>1))then
        error('x of f,or both ,not coloumn vector (s)')
        abort;
    end;
    if((xn<>yn))
then
        error ('x of f,or both,not of the same length')
        abort;
    end;
    if(modulo(xn-1,3)<>0)then
        disp(xn-1,"list size=");
        error("list size must be of the from 3*i+1, where i=integer");
            abort;
    end;
       n=xn;
       h=x(2)-x(1);
       i=f(1,1)+f(1,n);
       for j=2:n-1
           if(modulo(j-1,3)==0) then
               i=i+2*f(1,j)
           else
               i=i+3*f(1,j)
       end;
   end;
   i=(3/8)*h*i;
   printf('integration by simpson 3/8 rd rule = %f',i);
   endfunction

Output:

  x=(4:0.2:5.2);

  simp(x,log10(x));
integration by simpson 3/8 rd rule = 1.827847