Heuristic Search Methods
A heuristic (heuristic rule, heuristic method) is a rule of
thumb, strategy, trick, simplification, or any other kind of
device which drastically limits search for solutions in large
problem spaces. Heuristics do not guarantee optimal
solutions; in fact, they do not guarantee any solution at all: all
that can be said for a useful heuristic is that it offers
solutions which are good enough most of the time.
Feigenbaum and Feldman, 1963, p. 6
What is a heuristic?
Heuristic Search Methods
The blind-search methods ... are exhaustive methods for
finding paths to a goal state. In principle, these methods
provide a solution to the path-finding problem, but it is often
infeasible to use these methods because the search will
expand too many nodes before a path is found. ... For many
tasks it is possible to state principles or rules of thumb to help
reduce the search. Any such technique used to speed up the
search depends on special information about the problem
being represented by the graph. Let us call information of
this sort heuristic information (serving to aid discovery) and
call search procedures using it heuristic search methods.
Nilsson, 1971, p. 53
What is a heuristic?
