Fruit (chess engine)

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Fruit is a chess engine developed by Fabien Letouzey. In the SSDF rating list released on November 24, 2006, Fruit version 2.2.1 had a rating of 2842. In the CEGT rating list released on January 24, 2007, Fruit version 2.2.1 had a rating of 2776.

At the World Computer Chess Championship in Reykjavík in 2005, Fruit scored 8.5 out of 11, finishing in second place behind Zappa.

Until Version 2.1 (Peach), Fruit was an open source engine. The source of the version 2.1 is still open and contributed much to the development in computer chess in recent years. Some people still work on the old source code and have created variations from the original Fruit.

[edit] Technical details of Fruit 2.1

Fruit uses the classical Negascout (PVS) algorithm with Iterative deepening to traverse the game tree. It also uses the null-move heuristic. The original version used a simplistic evaluation function with a robust search. Later versions have improved evaluation functions. The board representation is distinct — Fruit uses a 16x12 board. It is a combination of the more popular 10x12 (mailbox) and 16x8 (0x88).

[edit] Derivatives

Toga II is a derivative created by Thomas Gaksch. It has more chess knowledge and perhaps a better search algorithm. It is based on Fruit 2.1 and is free.

GambitFruit is another free derivative of Fruit 2.1, created by Ryan Benitez. It plays a more aggressive style and has more chess knowledge. GambitFruit also incorporates improvements from Toga II.