Sample Resume : Beam Search Essay

1346 Words Feb 22nd, 2016 6 Pages
Beam search is an informed algorithm for searching a graph that extends the Breadth-First search (Jungwirth, 2006). The Breadth-First search is essentially a special-case Best-First search where the evaluation function, f(n) is the same as the heuristics function, h(n) (JONES, 2008). Therefore in order to properly discuss Beam search, there is the need for a brief introduction to Best-First algorithm.
The Best-First search traverses a tree from top to bottom and searches for nodes on the same level first before descending to the next level. Nodes on the search frontier (nodes on the same level) are selected based on some evaluating function that is defined depending on the nature of the problem (heuristics function) and the estimated cost. The evaluating function f(n) is therefore the sum of the heuristic function h(n) and the estimated cost g(n). This algorithm is complete as it will always find the solution if it exists but it not optimal as it might find a solution of longer length depending on the heuristic function applied. The time and space complexity is both O(bm) where b is the branching factor and m is the tree depth.
As a result of the exponential growth especially in memory requirements as the branching factor and tree depth increases, Best-First algorithm is not feasible for solving large search spaces. To solve the memory requirements issue associated with Best-First algorithm, a constraint can be imposed, called a beam width B that specifies a number for…

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