Writing a 'while loop'

Hello, I am trying to write a while loop and I want it to keep iterating until the answer converges to within 1.e-4 of the previous iteration. Every time I run this code, it only iterates it once. How would I go about fixing my first line so that it keeps running until the difference between the last two iterations is less than or equal to 1.3-4?

while (error>=1.e-4);%%This is where I am getting confused
  iteration=iteration+1;
  phi(:,iteration)=D\(rho-T*phi(:,iteration-1));
  error=norm(phi(:,iteration)-phi(:,iteration-1),Inf);
end

Thank you in advance for you help.

Answer 1

[Azzi Abdelmalek]

Initialize error to 1 for example

error=1
while (error>=1.e-4)
 %your code
end

[Jan]

No, do not use "error" as a variable, because this shadows a very important Matlab function. I assume that the OP does have problems with this already, therefore avoiding such shadowing is strongly recommended.