# Tag Info

I think you might have misunderstood the heuristic function. It is supposed to give an underestimate on the distance from a node $n$ to the goal node $t$. The closer this estimate is to the true value, the better A* will perform. The only criterion for the heuristic function is that it never gives a higher value for $h(n)$ than the true cost of going from $... 1 They can't possibly be on the same scale throughout the search, if by that you mean that$g(n) \approx h(n)$for every node encountered near the search. Near the start, you'll have$g(n) \approx 0$, so$g(n) \ll h(n)$. Near the goal node, you'll likely have$h(n) \approx 0$, so$h(n) \ll g(n)\$. On the other hand, it is possible to have the range of values ...