A heuristic resembles an algorithm except that it has a difference of a key. A heuristic is a rule of thumb that can be of help in order to solve a given problem. It considers the knowledge of the problem to aid the search process. (Jones, 2008) and aims at minimizing the number of nodes. An admissible function is a function that is a lowest-cost path to the target or in other words, a heuristic is admissible if it does not overestimate the cost (Russell amp. Norvig, 2002). It is the path evaluation function that A* uses to choose suitable paths through the search space (Copin, 2004). The other functions are consistent heuristic function and the incremental heuristic search. While former, solve problems without taking any step back, the later approaches solution by reusing previous searchesâ€™ information to pace.

A* Search Algorithm Artificial Intellegence