Reputation: 1929
How does the cost function work for the TSP? Say I have a tour which has a distance of 100, and I change the tour slightly, making 4 changes to the original and it now has a distance of 50.
Would the cost function give me 4, because that's the number of changes; or 50, because of the change in distance? Or maybe I'm missing something and it's neither?
Upvotes: 1
Views: 939
Reputation: 63
The cost function is the total distance, yes, but it is also the energy parameter $E$ in Simulated Annealing. It is not the "energy" $E$ that directly determines the probability of transitioning to that state, but it is rather $\Delta{E}$
, the change in energy (the change in cost), that determines the probability $P(\Delta{E})=exp(-\Delta{E}/T)$
.
So the transition from $E=100$ to $E=50$ would be $\Delta{E}=-50$
(100% probability).
The transition from $E=100$ to $E=150$ would be $\Delta{E}=50$, and a probability of ~0.7% if the temperature were 10. $P(\Delta{E}=50)=e^{-50/10}$
.
Upvotes: 1
Reputation: 3740
The cost function is the total distance.
It is exactly what you want to be minimal.
Upvotes: 1