Question

Which of these conditions is unstable?

(a) Error is amplified in increasing iterations

(b) Error is decreasing in increasing iterations

(c) Error is amplified in decreasing iterations

(d) Error is maintained in increasing iterations

The question was posed to me in an online interview.

My question comes from Discretization Aspects topic in division Basic Aspects of Discretization, Grid Generation with Appropriate Transformation of Computational Fluid Dynamics

Answer 1

Correct choice is (a) Error is amplified in increasing iterations

To elaborate: A system is said to be unstable if the error increases with the increasing iterations. So, for a system to be stable, the error should decrease or at least should be maintained in further iterations.