# Help with understanding Simulated Annealing algorithm

I'm trying to wrap my head around it, but no matter what I read, I still can't fully understand it.
I tried to read a little bit about the annealing process in physics, but I have no background whatsoever in physics, let alone in thermodynamics, so I couldn't understand what is it exactly, and how it fits into the algorithm.
Here is the algorithm:

In the Hill Climbing algorithm, the reasoning can be easily described: Of all the successors of the current state - choose the highest-valued. But in Simulated Annealing... well, I can see what the algorithm does, I just don't understand the reasoning behind it:
1. It starts a timer.
2. It chooses a random successor.
3. It evaluates how "far away" the randomly chosen successor from current.
4. If the successor is indeed a "progress in the right direction" ($\Delta E > 0$) then we move ahead towards the direction of successor; otherwise, we move ahead towards the direction of successor with some (odd) probability that depends on the timer(?).

Why is randomly choosing a successor better then the Hill Climbing method?
Can someone please explain the reasoning behind it?
Do I really have to understand the annealing process? If so, can someone please explain it in layman terms?

• What research and self-study have you done? The intuition behind simulated anneal is described in lots of resources, both textbooks and on the Internet -- not sure there's much point in repeating it here. P.S. We can't possibly answer "Do you really have to understand it?" -- ask your instructor. – D.W. Mar 28 '15 at 17:49

The variable $T$ is not a timer but the temperature. It starts very high, making it more likely that transitions are taken, and then slowly cools. It's called annealing due to the metallurgical technique of the same name.