Save old values in an iteration (while loop)

Hi,

In Newton_Raphson iteration, I need to compare old and new values of X so that it stops when their difference is very small. How can I save old values? Thank you very much in advance.

Answer 1

[Walter Roberson]

prev_value = inf;
while true
   new_value = .... some calculation
   if abs(prev_value - new_value) < YourTolerance
     break;
   end
   prev_value = new_value;
end