HAL

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|| [[image:HAL9000.jpg link="https://commons.wikimedia.org/wiki/File:HAL9000.svg"]] ||~ || **HAL**, (Heuristic Associative Linear-algorithm, HAL-9000, HAL9000)
an [[Open Source Engines|open source chess program]] by [[Stephen F. Wheeler]], also dubbed HAL-9000 as pun of [[https://en.wikipedia.org/wiki/HAL_9000|HAL 9000]], the fictional character in [[https://en.wikipedia.org/wiki/Arthur_C._Clarke|Arthur C. Clarke's]] [[https://en.wikipedia.org/wiki/Space_Odyssey|Space Odyssey series]], first appearing in [[https://en.wikipedia.org/wiki/2001:_A_Space_Odyssey_(film)|2001: A Space Odyssey]] <ref>[[Murray Campbell]] (**1997**). //"An Enjoyable Game": How HAL Plays Chess//. in [[https://mitpress.mit.edu/authors/david-g-stork|David G. Stork]] (ed.), //[[https://mitpress.mit.edu/books/hals-legacy|Hal's Legacy - 2001's Computer as Dream and Reality]]//. [[https://en.wikipedia.org/wiki/MIT_Press|MIT-Press]], [[http://web.stanford.edu/class/sts145/Library/campbell.pdf|pdf]]</ref> <ref>[[http://www.stmintz.com/ccc/index.php?id=357151|An interesting link]] by [[Steven Edwards]], [[CCC]], March 29, 2004</ref>. HAL was written in [[Pascal#TurboPascal|Turbo Pascal]] to run under the [[MS-DOS]] [[CLI|command line]], and was part of Wheeler's Ph.D. research during the late 80s and early 90s <ref>[[http://newsroom.devry.edu/distinguished-faculty/college-engineering-information-sciences/stephen-f-wheeler-senior-professor-college-engineering-information-sciences-irving-tx-campus.htm|Stephen F. Wheeler, Senior Professor, College of Engineering & Information Sciences, Irving, TX Campus | DeVry University Newsroom]]</ref>, specifically on [[https://en.wikipedia.org/wiki/Linearity|linear]] [[https://en.wikipedia.org/wiki/Symbolic_computation|symbolic]] [[https://en.wikipedia.org/wiki/Problem_solving|problem-solving]] systems and [[https://en.wikipedia.org/wiki/Natural_language_processing|natural language processing]]. A slightly modified and bug fixed version was published with source in December 2015 at [[https://en.wikipedia.org/wiki/Chess.com|Chess.com]] <ref>[[https://schach.chess.com/index.php/download/view/hal-9000|HAL-9000]] by [[https://schach.chess.com/members/view/sfwheeler|sfwheeler]], [[https://en.wikipedia.org/wiki/Chess.com|Chess.com]]</ref>.  ||
|| HAL 9000 <ref>The famous red eye of [[https://en.wikipedia.org/wiki/HAL_9000|HAL 9000]], the fictional character in [[https://en.wikipedia.org/wiki/Arthur_C._Clarke|Arthur C. Clarke's]] [[https://en.wikipedia.org/wiki/Space_Odyssey|Space Odyssey]] series. [[https://commons.wikimedia.org/wiki/File:HAL9000.svg|Image]] by Cryteria, October 1, 2010, [[https://en.wikipedia.org/wiki/Wikimedia_Commons|Wikimedia Commons]]</ref> ||~ ||^ ||
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=Description=
==User Interface==
HAL has a [[CLI|command line interface]], and supports an interactive English dialogue between the opponent and itself to [[Entering Moves|receive]] and report its moves and to receive directives, such as skill level. The directives are given to HAL in the form of English sentences, which can be rather free-form in structure, and will even allow for slight misspellings in certain situations. HAL utilizes the [[Algebraic Chess Notation#LAN|long algebraic notation]] <ref>[[https://schach.chess.com/index.php/download/view/hal-9000|HAL-9000]], HAL-9000.zip/HALDOC.DOC</ref> <ref>[[https://schach.chess.com/index.php/download/view/hal-9000|HAL-9000]], HAL-9000.zip/CP3.pas</ref>.

==Board Representation==
HAL's [[Board Representation|board is represented]] by an [[Incremental Updates|incremental updated]] [[8x8 Board|8x8 board]], a two-dimensional [[Array|array]] of board cells, and a [[Piece-Lists|piece-list]] as array of piece cells indexed by side (1..2) and man index 1..16.

==Search==
The [[Search|search]] algorithm is pure [[Alpha-Beta|alpha-beta]] implemented as [[Recursion|recursive]] [[Negamax|negamax]] with [[Fail-Soft|fail-soft]] bounds inside the [[Iterative Deepening|iterative deepening]] framework with [[Aspiration Windows|aspiration windows]]. [[Move Ordering|Move ordering]] is improved by the [[Refutation Table|refutation table]] based on the [[Triangular PV-Table|triangular PV-table]], and a sophisticated [[Killer Heuristic|killer heuristic]] with up to four [[Killer Move|killers]] per [[Ply|ply]]. [[Selectivity]] is due to [[Check Extensions|check extensions]] and depth limited [[Quiescence Search|quiescence search]].

==Evaluation==
[[Evaluation]] considers [[Material|material balance]], a material exchange heuristic, and positional heuristic terms for [[Development|development]], [[King Safety|king attack]], [[Square Control|defence]], threats, [[Mobility|mobility]], advancement, [[Captures|captures]] and [[Check|checks]].

=See also=
* [[Marvin Minsky#HAL9000|Marvin Minsky | HAL 9000]]
* [[SAL]]

=Postings=
* [[http://www.stmintz.com/ccc/index.php?id=120859|Off-topic: HAL]] by [[Dave Gomboc]], [[CCC]], July 19, 2000
* [[http://www.stmintz.com/ccc/index.php?id=239756|Frank Poole v HAL 9000 -- or is it CM9000?]] by [[John Merlino]], [[CCC]], July 10, 2002 » [[Chessmaster]]
* [[https://www.chess.com/forum/view/general/hal9000-levels-of-play|HAL9000 Levels of Play]] by [[Stephen F. Wheeler]],  [[https://en.wikipedia.org/wiki/Chess.com|Chess.com]], May 22, 2010
* [[https://schach.chess.com/forum/view/general/hal9000-chess-rating|HAL9000 Chess Rating?]] by [[Stephen F. Wheeler]],  [[https://en.wikipedia.org/wiki/Chess.com|Chess.com]], May 28, 2010

=External Links=
==Chess Program==
* [[https://schach.chess.com/index.php/download/view/hal-9000|HAL-9000]] by [[https://schach.chess.com/members/view/sfwheeler|sfwheeler]], [[https://en.wikipedia.org/wiki/Chess.com|Chess.com]]
==Fictional Character==
* [[https://en.wikipedia.org/wiki/HAL_9000|HAL 9000  from Wikipedia]]
* [[https://en.wikipedia.org/wiki/Poole_versus_HAL_9000|Poole versus HAL 9000  from Wikipedia]]
* [[https://commons.wikimedia.org/wiki/Category:HAL_9000|Category:HAL 9000]] from [[https://en.wikipedia.org/wiki/Wikimedia_Commons|Wikimedia Commons]]
* [[https://en.wikiquote.org/wiki/2001:_A_Space_Odyssey_(film)#HAL_9000|2001: A Space Odyssey | HAL 9000  - Wikiquote]]

=References= 
<references />
=What links here?= 
[[include page="HAL" component="backlinks" limit="40"]]
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