NegaC*

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C* and NegaC*, an idea to turn a Depth-First to a Best-First search, like MTD(f) to utilize null window searches of a fail-soft Alpha-Beta routine, and to use the bounds that are returned in a bisection scheme. This yields in the C* algorithm, already proposed by Kevin Coplan in 1981 along with his chess machine Virgo and NegaC*, a NegaMax implementation of C*, introduced by Jean-Christophe Weill in 1991.

=NegaC* Pseudo Code= int negaCStar (int min, int max, int depth) { int score = min; while (min != max) { alpha = (min + max) / 2; score = failSoftAlphaBeta (alpha, alpha + 1, depth); if ( score > alpha) min = score; else max = score; }  return score; }

=See also=
 * Alpha-Beta
 * Fail-Soft
 * MTD(f)
 * Negamax
 * NegaScout
 * Null Window
 * Principal Variation Search
 * Scout
 * SSS* and Dual* as MT

=Publications=
 * Kevin Coplan (1982). A special-purpose machine for an improved search algorithm for deep chess combinations. Advances in Computer Chess 3
 * Kevin Coplan (1984). The experimental and theoretical validation of a new search algorithm with a note on the automatic generation of causual explanations. Ph.D. thesis, University of Edinburgh, pdf
 * Wolfgang Nagl (1989). Best-Move Proving: A Fast Game Tree Searching Program. Heuristic Programming in AI 1
 * Jean-Christophe Weill (1991). Experiments With the NegaC* Search - An Alternative for Othello Endgame Search. Heuristic Programming in AI 2
 * Jean-Christophe Weill (1992). The NegaC* Search. ICCA Journal, Vol. 15, No. 1

=Forum Posts=
 * Re: Interesting ideas by Dann Corbit, CCC, September 09, 2015

=References=

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