Not showing the number of iterations in the output

Hey i had this project to write a matlab program that solves a problem using jacobi method.i was given a linear equation to solve. here is my program

function hw6
  clear;clc;
  n=3;

    Jac=zeros(n); fv=zeros(n,1); f=zeros(n,1);
    x=[0;0;0];
    itr_max=100; tol=10^-4;
    for k=1:itr_max
      Jac=J(x);
      fv=fx(x);
      f=-1.*fv';
      d=Jac\f;
      x=x+d;
      Rerr=abs(d./x);
      fprintf('x1=%f Rerr1=%f x2=%f Rerr2=%f x3=%f        Rerr3=%f\n',x(1),Rerr(1),x(2),Rerr(2),x(3),Rerr(3))
      max_err=max(Rerr);
      if max_err<tol; 
        break; 
      end;
    end
    if k==itr_max
      fprintf('Newtons method failed to converge in %d iterations\n',itr_max)
      if 1i<itr_max
        fprintf('The solution is x(1)=%f x(2)=%f and x(3)=%f in %d iterations\n',x,k)
      end
    end

function Jac=J(~)
  Jac(1,1)=4; Jac(1,2)=-2; Jac(1,3)=1;
  Jac(2,1)=2; Jac(2,2)=5; Jac(2,3)=-2;
  Jac(3,1)=1; Jac(3,2)=-1; Jac(3,3)=-3;
end

function  fv=fx(x)
  fv(1)=4*x(1)-2*x(2)+x(3)-3;
  fv(2)=2*x(1)+5*x(2)-2*x(3)-2;
  fv(3)=x(1)-x(2)-3*x(3)-0.1;
end
end

it was suppose to show the number of iterations in the output but apparently it didnt show it. please what am i doing wrong.

Answer 1

[dpb]

The second fprintf statement is nested inside the first if...end test on the loop having completed the maximum number of allowed iterations; hence nothing will print if the algorithm succeeds in fewer.

Rewrite the if logic to account for that...one option w/ minimal changing of your code could be

if k>=itr_max
    fprintf('Newton's method failed to converge in %d iterations\n',itr_max)
else
  fprintf('The solution is x(1)=%f x(2)=%f and x(3)=%f in %d iterations\n',x,k)
end

The above suffers from one logic flaw, however, can you spot it? Hint: it's at the end boundary condition...