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. A chess engine is a computer program that can play the game of chess. ... The Swedish Chess Computer Association (Svenska schackdatorföreningen (SSDF) in Swedish) is an organization that tests computer chess software by playing chess programs against one another and producing a rating list. ... November 24 is the 328th day (329th in leap years) of the year in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... Chess Go The Elo rating system is a method for calculating the relative skill levels of players in two-player games such as chess and Go. ... January 24 is the 24th day of the year in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... Chess Go The Elo rating system is a method for calculating the relative skill levels of players in two-player games such as chess and Go. ...

At the World Computer Chess Championship in Reykjavík in 2005, Fruit scored 8.5 out of 11, finishing in second place behind Zappa. World Computer Chess Championship (WCCC) is an annual event where computer chess engines compete against each other. ... Location in Iceland Coordinates: Constituency Reykjavík North Reykjavík South Government  - Mayor (Borgarstjóri) Vilhjálmur Þ. Vilhjálmsson Area  - City 274. ... Zappa is a chess engine written by Anthony Cozzie, a graduate student at the University of Illinois at Urbana-Champaign. ...

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. Open source refers to projects that are open to the public and which draw on other projects that are freely available to the general public. ...

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). NegaScout or Principal Variation Search is a minimax algorithm faster than alpha-beta pruning. ... Iterative deepening depth-first search is a state space search strategy, that visits each node in the search tree in the same order as breadth-first search but does so by gradually increasing the maximum depth limit of the search iteratively. ... In computer chess programs, the null-move heuristic is a heuristic technique used to enhance the speed of the alpha-beta pruning algorithm. ... An evaluation function, also known as heuristic evaluation function or static evaluation function by game-playing programs to estimate the value or goodness of a position in the minimax algorithm. ... In computer chess software developers must choose a data structure to represent chess positions. ...

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.

External links

• Official Fruit Homepage
• Fruit 2.1 source
• Official distribution web site (2.1 and below)
• Toga
• GambitFruit