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Internal Iterative Deepening

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'''[[Main Page|Home]] * [[Search]] * [[Move Ordering]] * Internal Iterative Deepening'''
[[FILE:Henry Moore at Kew Gardens 563.JPG|border|right|thumb|260px|[[:Category:Henry Moore|Henry Moore]]: - Large Upright Internal/External Form <ref>[[:Category:Henry Moore|Henry Moore]] sculpture [https://de.wikipedia.org/wiki/Henry_Moore_Sculpture_Perry_Green Large Upright Internal/External Form] (1981/1982) at [https://en.wikipedia.org/wiki/Kew_Gardens Kew Gardens], [https://en.wikipedia.org/wiki/London London], at an extensive exhibition of his work in 2007, [https://commons.wikimedia.org/wiki/File:Henry_Moore_at_Kew_Gardens_563.JPG image] by [https://commons.wikimedia.org/wiki/User:Patche99z Patche99z], October 29, 2007, [https://en.wikipedia.org/wiki/Wikimedia_Commons Wikimedia Commons]</ref> ]]
'''Internal Iterative Deepening (IID)''',<br/>
used in [[Node|nodes]] of the [[Search Tree|search tree]] in a [[Iterative Deepening|iterative deepening]] [[Depth-First|depth-first]] [[Alpha-Beta|alpha-beta]] framework, where a program has no [[Best Move|best move]] available from a previous search [[Principal Variation|PV]] or from the [[Transposition Table|transposition table]]. '''IID''' is used to find a good move to search first by searching the current position to a reduced depth, and using the best move of that search as the first move at the real depth. IID was already introduced by [[John J. Scott]] in 1969 inside his program [[Lancaster]] <ref>[[John J. Scott]] ('''1969'''). ''A chess-playing program''. [http://www.doc.ic.ac.uk/~shm/MI/mi4.html Machine Intelligence 4] </ref>, and further elaborated by [[Thomas Anantharaman]] in 1991 <ref>[[Thomas Anantharaman]] ('''1991'''). ''Extension Heuristics''. 1.12 Internal iterative deepening, [[ICGA Journal#14_2|ICCA Journal, Vol. 14, No. 2]]</ref>, as used in [[Deep Thought]] with a reduction of 2 [[Ply|plies]] at [[Node Types#PV|PV-nodes]] and [[Node Types#CUT|cut-nodes]] with no [[Best Move|best-move]] information from the transposition table. While it is pretty much a washout on average, Deep Though used this heuristic since it makes the search times more predictable by avoiding those isolated instances when the search time suddenly becomes 10 times larger than expected <ref>[[John J. Scott]] and [[Thomas Anantharaman]] referred in [[Eli David|Omid David]], [[Moshe Koppel]], and [[Nathan S. Netanyahu]] ('''2010'''). ''Genetic Algorithms for Automatic Search Tuning''. [[ICGA Journal]]#33_2|ICGA Journal, Vol. 33, No. 2]], pp. 67--79</ref>.
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=References=
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'''[[Move Ordering|Up one level]]'''
[[Category:Henry Moore]]

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