Freyr, a WinBoard compliant open source chess engine written by Andrei Fortuna in C++, intended as a test ground for various chess algorithms, first released in February 2000. Freyr is a bitboard engine and uses rotated bitboards to determine sliding piece attacks. The search is PVS [1] with null move pruning inside an aspiration window iterative deepening framework with transposition table, using several move ordering heuristics, such as killer, history and countermove, as well as SEE to order captures. Lazy evaluation considers incremental updated material- and piece-square table scores and cached pawn structure stuff. Evaluation further includes king safety and passed pawns as most dominant terms [2].
Freyr and Gullinbursti[3]

See also

• Mythology
• Thor's Hammer

Forum Posts

• New Winboard Program by Đorđe Vidanović, Winboard Forum, February 15, 2000
• A New Release of my Amateur Chess Engine Freyr by Andrei Fortuna, CCC, February 22, 2000
• Freyr 0.960 released by Andrei Fortuna, Winboard Forum, February 29, 2000
• A Question on simple Alpha-Beta versus PVS/Negascout by Andrei Fortuna, CCC, March 21, 2000 » Alpha-Beta, Principal Variation Search, NegaScout
• Freyr 0.987 Released by Andrei Fortuna, Winboard Forum, April 30, 2000
• Freyr 1.015 Released by Andrei Fortuna, Winboard Forum, May 29, 2000
• Freyr 1.024 sees the daylight by Andrei Fortuna, Winboard Forum, June 02, 2000
• Freyr 1.067 by Andrei Fortuna, Winboard Forum, September 15, 2000

External Links

Chess Engine

• Planet Source Code™ | Freyr - A Chess Playing Program by Andrei Fortuna
• Freyr 1.068 64-bit in CCRL 40/4

Misc

• Freyr from Wikipedia
  Yngvi-Freyr from Wikipedia
• Frey (disambiguation) from Wikipedia
• Freyja from Wikipedia

References

1. ^ A Question on simple Alpha-Beta versus PVS/Negascout by Andrei Fortuna, CCC, March 21, 2000
2. ^ Planet Source Code™ | Freyr - A Chess Playing Program by Andrei Fortuna
3. ^ "Freyr" by Johannes Gehrts. The god Freyr stands with his sword and the boar Gullinbursti. Source: Felix Dahn, Therese Dahn (1901). Walhall: Germanische Götter- und Heldensagen. Für Alt und Jung am deutschen Herd. Breitkopf & Härtel, Freyr from Wikipedia

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