Gullydeckel

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Manhole cover in Rome

Gullydeckel,
a Chess Engine Communication Protocol compliant open source engine under the GNU General Public License written in C by Martin Borriss. Supported platforms are Linux and Windows.

Features

Board Representation

• Piece-Lists
• 0x88

Search

• Iterative Deepening
• Aspiration Windows
• Alpha-Beta
• Transposition Table
• Null Move Pruning, R=2
• Check Extensions
• Quiescence Search
• Static Exchange Evaluation
• Killer Heuristic
• History Heuristic

Evaluation

• Material
• Imbalance Table
• Lazy Evaluation
• Piece-Square Tables
• Rooks on (Semi) Open Files
• Rook on 7th Rank
• Pawn Structure
• Pawn Hash Table
• Weak Pawns
• Passed Pawn
• King Safety

0x88 Difference

The pre-initialized static int vector[256] in "attacks.c" with ray directions encoded, which is indexed by 0x88 square difference plus offset, somehow reminds on a Gullydeckel, the colloquial German name for Manhole cover :

/*
if we find that two squares are related according to matrix SqRel,
we use another matrix to look up the direction of the move required
('to walk the vector') if it is a sliding piece (R,B,Q)
*/

static int vector[256] = {
   0  ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,UR,0 ,0 ,0 ,0 ,0 ,0 ,
   UP ,0 ,0 ,0 ,0 ,0 ,0 ,UL,0 ,0 ,UR,0 ,0 ,0 ,0 ,0 ,
   UP ,0 ,0 ,0 ,0 ,0 ,UL,0 ,0 ,0 ,0 ,UR,0 ,0 ,0 ,0 ,
   UP ,0 ,0 ,0 ,0 ,UL,0 ,0 ,0 ,0 ,0 ,0 ,UR,0 ,0 ,0 ,
   UP ,0 ,0 ,0 ,UL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,UR,0 ,0 ,
   UP ,0 ,0 ,UL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,UR,0 ,
   UP ,0 ,UL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,UR,
   UP ,UL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,RI,RI,RI,RI,RI,RI,RI,
   0  ,LE,LE,LE,LE,LE,LE,LE,0 ,0 ,0 ,0 ,0 ,0 ,0 ,DR,
   DN ,DL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,DR,0 ,
   DN ,0 ,DL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,DR,0 ,0 ,
   DN ,0 ,0 ,DL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,DR,0 ,0 ,0 ,
   DN ,0 ,0 ,0 ,DL,0 ,0 ,0 ,0 ,0 ,0 ,DR,0 ,0 ,0 ,0 ,
   DN ,0 ,0 ,0 ,0 ,DL,0 ,0 ,0 ,0 ,DR,0 ,0 ,0 ,0 ,0 ,
   DN ,0 ,0 ,0 ,0 ,0 ,DL,0 ,0 ,DR,0 ,0 ,0 ,0 ,0 ,0 ,
   DN ,0 ,0 ,0 ,0 ,0 ,0 ,DL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0
 };

Forum Posts

• Re: Deep Quiesence Searching by Martin Borriss, rgcc, February 26, 1997
• Re: Deep Quiesence Searching by Martin Borriss, rgcc, February 26, 1997
• Gullydeckel - move generator by Thomas Mayer, CCC, December 20, 2000

External Links

Chess Engine

• Gullydeckel Chess Program
• GitHub - borriss/gully: Gullydeckel Chess Program
• Gullydeckel 2.16pl1 in CCRL 40/4

Misc

• Gullydeckel – Wiktionary.de (German)
• Schachtdeckel Wikipedia.de (German)
• Manhole cover from Wikipedia
• Storm drain from Wikipedia
• Sanitary sewer from Wikipedia
• Gully (disambiguation) from Wikipedia
• Manhole cover - Wikimedia Commons

References

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