MCαβ

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Monte-Carlo Alpha-Beta, (MCαβ) is a Best-First search algorithm based on Monte-Carlo Tree Search and a shallow alpha-beta depth-first-search. It is used in Lines of Action and in conjunction with UCT (Upper Confidence bounds applied to Trees) also in Chess. It is similar to the the Best-first minimax search proposed by Richard Korf and Max Chickering, one distinction between the two might be that MCTS uses usually win/draw/loss scores and BestFirst a score from a heuristic evaluation function. =Four Phases= MCαβ can be divided into four strategic phases, repeated as long as there is time left:
 * 1) In the Selection phase the tree is traversed from the root node until it selects a leaf node that is not added to the tree yet
 * 2) The Expansion strategy adds the leaf node to the tree
 * 3) The Playout phase performs a shallow alpha-beta search
 * 4) The Backpropagation strategy propagates the results through the tree

=See also=
 * Alpha-Beta
 * Best-First Minimax Search
 * Minimax
 * Monte-Carlo Tree Search
 * MT-SSS*
 * Rocinante
 * Rollout Paradigm

=Publications=
 * Richard Korf, Max Chickering (1996). Best-First Minimax Search. Artificial Intelligence, Vol. 84, No 1-2
 * Pim Nijssen, Mark Winands (2011). Playout Search for Monte-Carlo Tree Search in Multi-Player Games. Advances in Computer Games 13, pdf
 * Cameron Browne, Edward Powley, Daniel Whitehouse, Simon Lucas, Peter Cowling, Philipp Rohlfshagen, Stephen Tavener, Diego Perez, Spyridon Samothrakis, Simon Colton (2012). A Survey of Monte Carlo Tree Search Methods. IEEE Transactions on Computational Intelligence and AI in Games, Vol. 4, No. 1, pdf
 * Hendrik Baier, Mark Winands (2013). Monte-Carlo Tree Search and minimax hybrids. CIG 2013, pdf
 * Hendrik Baier, Mark Winands (2014). Monte-Carlo Tree Search and Minimax Hybrids with Heuristic Evaluation Functions. ECAI CGW 2014
 * Bojun Huang (2015). Pruning Game Tree by Rollouts. AAAI » MCTS, MT-SSS*, Rollout Paradigm
 * Hendrik Baier (2017). A Rollout-Based Search Algorithm Unifying MCTS and Alpha-Beta. Computer Games

=Forum Posts=
 * MCTS without random playout? by Antonio Torrecillas, CCC, January 01, 2012 » B*
 * Help with Best-First Select-Formula by Srdja Matovic, CCC, July 23, 2012
 * Re: Announcing lczero by Daniel Shawul, CCC, January 21, 2018 » Leela Chess Zero
 * Alpha-Beta as a rollouts algorithm by Daniel Shawul, CCC, January 25, 2018 » Alpha-Beta, Monte-Carlo Tree Search, Scorpio

=External Links=
 * Larry Coryell & The Eleventh House, Oslo 1975, YouTube Video
 * feat. Mike Lawrence, Alphonse Mouzon, John Lee, Mike Mandel

=References=

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