Jaap van den Herik

WCCC 2017: The 23 rd World Computer Chess Championship

The ICGAs 23rd World Computer Chess Championship started on July 3rd. 2017. The competitors in this select field were CHIRON, JONNY, KOMODO and SHREDDER. The contest was close and set new standards for the event: all podium places required play-offs. Ultimately, KOMODO retained its title, beating JONNY and SHREDDER. The analysis of the games and the pgn file of games are provided here.

WCCC 2016: the 22nd World Computer Chess Championship

In the ICGAs 22nd World Computer Chess Championship in Leiden, six contestants together gave the latest demonstration of the state of the art in chess-playing programs. This article highlights the advances and subtleties exemplified by their play. The new World Champion was KOMODO with JONNY, edged out in the play-off, second and SHREDDER third. GRIDGINKGO, HIARCS and RAPTOR took the remaining places.

A Lock-free Algorithm for Parallel MCTS.

In this paper, we present a new lock-free tree data structure for parallel Monte Carlo tree search (MCTS) which removes synchronization overhead and guarantees the consi stency of computation. It is based on the use of atomic operations and the associated memory ordering guara ntees. The proposed parallel algorithm scales very well to higher numbers of cores when compared to the exis ting methods.

Pipeline Pattern for Parallel MCTS.

In this paper, we present a new algorithm for parallel Monte C arlo tree search (MCTS). It is based on the pipeline pattern and allows flexible management of the contr ol flow of the operations in parallel MCTS. The pipeline pattern provides for the first structured parallel programming approach to MCTS. The Pipeline Pattern for Parallel MCTS algorithm (called 3PMCTS) scales very wel l to a higher number of cores when compared to the existing methods. The observed speedup is 21 on a 24-co re machine.

WSCC 2016: the World Speed Computer Chess Championship

In the ICGAs World Speed Computer Chess Championship, played at Blitz tempo, the role of the operators is more to the fore, their handspeed being crucial in building up the time available to the chess programs to ponder as necessary. The six contestants of the 2016 World Championship took part and the winner, on tie-break from SHREDDER, was JONNY. KOMODO, the 2016 Chess and Chess Software World Champion was third.

Ensemble UCT Needs High Exploitation

Recent results have shown that the MCTS algorithm (a new, adaptive, randomized optimization algorithm) is effective in a remarkably diverse set of applications in Artificial Intelligence, Operations Research, and High Energy Physics. MCTS can find good solutions without domain dependent heuristics, using the UCT formula to balance exploitation and exploration. It has been suggested that the optimum in the exploitation-exploration balance differs for different search tree sizes: small search trees needs more exploitation; large search trees need more exploration. Small search trees occur in variations of MCTS, such as parallel and ensemble approaches. This paper investigates the possibility of improving the performance of Ensemble UCT by increasing the level of exploitation. As the search trees become smaller we achieve an improved performance. The results are important for improving the performance of large scale parallelism of MCTS.

WCCC 2015: The 21st World Computer Chess Championship

Nine chess programs competed in July 2015 in the ICGAs World Computer Chess Championship at the Computer Science department of Leiden University. This is the official report of the event.