Heuristic
Definition
Heuristic is the art and science of discovery. The word comes from the same Greek root as "eureka", meaning "to find". A heuristic for a given problem is a way of directing your attention fruitfully to a solution. It is different from an algorithm in that it merely serves as a rule of thumb or guideline, as opposed to an invariant procedure. Heuristics may not always achieve the desired outcome, but can be extremely valuable to problem-solving processes. Good heuristics can dramatically reduce the time required to solve a problem by eliminating the need to consider unlikely possibilities or irrelevant states. --http://en.wikipedia.org/wiki/Heuristic
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