Utility Functions - artificial intelligence:

A goal based on an agent for playing chess is infeasible: at every moment it decides which move to play next, it sees whether that it will move eventually lead to a checkmate. As a choice it would be better for the agent to accesses it's progress not against the overall goal, but against a localized calculation. An agent's programs often have a utility function which calculates a numerical value for each world state the agent would find it in if it undertook a particular action. Then it can verify which action would make to the top most value being returned from the set of actions it has on hand. Usually the best action with respect to a utility function is undertaken, as this is the rational thing to do. The purpose of the agent is to find something by finding, if it uses a utility function in this method is known as a best first track.                         

RHINO searched for paths from its present location to an exhibit, using the distance from the show off as a utility function. However, this was difficult by visitors getting in the way.