Ryan Hayward

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Ryan Bruce Hayward, a Canadian mathematician, computer scientist, and professor at Department of Computing Science at University of Alberta. Ryan Hayward is particularly interested in Hex, which he learned from Claude Berge. As member of the University of Alberta's GAMES research group, he leads a team that developed Hex solver and players.

=Hex Programs= After early trials with Mongoose, the Hex programs Wolve (2008) and MoHex (2009, 2010, 2011, 2013, 2015 and 2017) won Gold Medals in Hex at the Computer Olympiad.

Wolve
Wolve does a truncated Alpha-Beta search of two and up to four plies, considering the huge Branching Factor of Hex.

MoHex
Since 2009 Monte-Carlo Tree Search starts to dominate, and MoHex applies MCTS along with the UCT framework combined with the allmoves-as-first (AMAF) heuristic to select the best child during tree traversal.

MoHex-CNN
MoHex-CNN, which won the 13x13 competition of the 20th Computer Olympiad 2017 is a convolutional neural net (CNN) version of MoHex. At each new node of the Monte-Carlo search tree, a policy CNN biases child selection by initializing child visit and win counts with artificial values.

=Selected Publications=

2000 ...

 * Ryan Hayward, Yngvi Björnsson, Michael Johanson, Morgan Kan, Nathan Po, Jack van Rijswijck (2003). Solving 7x7 Hex: Virtual Connections and Game-state Reduction. Advances in Computer Games 10, pdf
 * Gábor Melis, Ryan Hayward (2003). Six wins Hex Tournament. ICGA Journal, Vol. 26, No. 4, pdf » 8th Computer Olympiad

2005 ...

 * Ryan Hayward, Yngvi Björnsson, Michael Johanson, Morgan Kan, Nathan Po, Jack van Rijswijck (2005). Solving 7x7 Hex with domination, fill-in, and virtual connections. Theoretical Computer Science, 349(2):123–139, 2005. pdf
 * Yngvi Björnsson, Ryan Hayward, Michael Johanson, Jack van Rijswijck (2006). Dead Cell Analysis in Hex and the Shannon Game. In Graph Theory in Paris: Proceedings of a Conference in Memory of Claude Berge (CT'04 Paris), pp. 45–60, 2006. zipped ps
 * Ryan Hayward, Jack van Rijswijck (2006). Hex and Combinatorics. Discrete Math 306, pdf
 * Ryan Hayward (2006). Six Wins Hex tournament. ICGA Journal, Vol. 29, No 3, pdf » 11th Computer Olympiad
 * Ryan Hayward, Broderick Arneson, Philip Henderson (2006). Automatic Strategy Verification for Hex. CG 2006, pdf
 * Philip Henderson, Ryan Hayward (2008). Probing the 4-3-2 Edge Template in Hex. CG 2008, pdf
 * Broderick Arneson, Ryan Hayward, Philip Henderson (2009). Wolve 2008 wins Hex tournament. ICGA Journal, Vol. 32, No. 1 » 13th Computer Olympiad
 * Philip Henderson, Broderick Arneson, Ryan Hayward (2009). Solving 8×8 Hex. IJCAI-09, pdf
 * Broderick Arneson, Ryan Hayward, Philip Henderson (2009). MoHex wins Hex tournament. ICGA Journal, Vol. 32, No. 2, pdf » 14th Computer Olympiad

2010 ...

 * Philip Henderson, Broderick Arneson, Ryan Hayward (2010). Hex, Braids, the Crossing Rule, and XH-Search. Advances in Computer Games 12, pdf
 * Broderick Arneson, Ryan Hayward, Philip Henderson (2010). MoHex wins Hex Tournament. ICGA Journal, Vol. 33, No. 3, pdf » 15th Computer Olympiad
 * Broderick Arneson, Ryan Hayward, Philip Henderson (2010). Solving Hex: Beyond Humans. CG 2010, pdf
 * Broderick Arneson, Ryan Hayward, Philip Henderson (2010). Monte Carlo Tree Search in Hex. IEEE Transactions on Computational Intelligence and AI in Games, Vol. 2, No. 4, pdf
 * Henry Brausen, Ryan Hayward, Martin Müller, Abdul Qadir, David Spies (2011). Blunder Cost in Go and Hex. Advances in Computer Games 13
 * Ryan Hayward (2012). MoHex wins Hex Tournament. ICGA Journal, Vol. 35, No. 2 » 16th Computer Olympiad
 * Ryan Hayward, Broderick Arneson, Shih-Chieh Huang, Jakub Pawlewicz (2013). MOHEX Wins Hex Tournament. ICGA Journal, Vol. 36, No. 3, pdf » 17th Computer Olympiad
 * Shih-Chieh Huang, Broderick Arneson, Ryan Hayward, Martin Müller, Jakub Pawlewicz (2013). MoHex 2.0: a pattern-based MCTS Hex player. CG 2013, pdf
 * Jakub Pawlewicz, Ryan Hayward (2013). Scalable Parallel DFPN Search. CG 2013

2015 ...

 * Jakub Pawlewicz, Ryan Hayward (2015). Feature Strength and Parallelization of Sibling Conspiracy Number Search. Advances in Computer Games 14
 * Jakub Pawlewicz, Ryan Hayward (2015). Sibling Conspiracy Number Search. SoCS 2015
 * Jakub Pawlewicz, Ryan Hayward (2016). Conspiracy number search with relative sibling scores. Theoretical Computer Science, Vol. 644
 * Kenny Young, Ryan Hayward (2016). A Reverse Hex Solver. CG 2016
 * Ryan Hayward, Jakub Pawlewicz, Kei Takada, Tony van der Valk (2017). MOHEX Wins 2015 Hex 11x11 and Hex 13x13 Tournaments. ICGA Journal, Vol. 39, No. 1 » 18th Computer Olympiad
 * Noah Weninger, Ryan Hayward (2017). Exploring Positional Linear Go. Advances in Computer Games 15, pdf
 * Ryan Hayward, Noah Weninger (2017). Hex 2017: MoHex wins the 11x11 and 13x13 tournaments. ICGA Journal, Vol. 39, Nos. 3-4 » 20th Computer Olympiad 2017
 * Chao Gao, Martin Müller, Ryan Hayward (2017). Focused Depth-first Proof Number Search using Convolutional Neural Networks for the Game of Hex. IJCAI 2017
 * Chao Gao, Siqi Yan, Ryan Hayward, Martin Müller (2018). A transferable neural network for Hex. CG 2018, ICGA Journal, Vol. 40, No. 3
 * Chao Gao, Kei Takada, Ryan Hayward (2019). Hex 2018: MoHex3HNN over DeepEzo. ICGA Journal, Vol. 41, No. 1 » 21st Computer Olympiad 2018

2020 ...

 * Ryan Hayward, et al. (2021). BoxOff is NP-complete. Advances in Computer Games 17

=External Links=
 * Webpage of Ryan B. Hayward
 * Ryan Hayward - Faculty of Science - University of Alberta
 * Ryan Hayward's ICGA Tournaments
 * The Mathematics Genealogy Project - Ryan Hayward

=References=

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