Find absolute distance from goal for each node. choose node with shortest distance.
Cost of each is \(f(n)=h(n)\), where \(h(n)\) is the heuristic cost of node \(n\).
If the heuristic is admissible, then a* is optimal. Intuitively because the the heuristic steers away from any suboptimal solutions.
Admissible? For all nodes n , h(n)<=h*(n). where h* is true cost
\(f(n)=g(n)+h(n)\)
\(g(n)\) is the cost to reach \(n\) from the current position.
Informed: Yes
Time: Exponential
Space: Big, all nodes kept in memory
Complete: Yes
Optimal: Yes, if the heuristic is admissible
Generating heuristics for search. we can losen restriction to get a much simpler problem and rank moves by how good they are for loosened problem.
eg for for path to goal, assume can go directly from next place in a straight line.