Difference between revisions of "Calculon"
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Calculon's ''getPiece'' routine to get a the [[Pieces#PieceTypeCoding|piece code]] of a square (the least significant one-bit of the passed bitboard pos, typically single populated) | Calculon's ''getPiece'' routine to get a the [[Pieces#PieceTypeCoding|piece code]] of a square (the least significant one-bit of the passed bitboard pos, typically single populated) | ||
| − | from the | + | from the [[Bitboard Board-Definition#SixTwo|six piece bitboards]] of its [[Board Representation|board representation]] is an idiosyncratic sample in avoiding a redundant [[8x8 Board|8x8 board]] as well in [[Avoiding Branches|avoiding branches]]. |
Taking the [[General Setwise Operations#Union|union]] (val) of six piece-specific [[General Setwise Operations#Rotate|rotates]] (left by 1..6) of six piece disjoint [[General Setwise Operations#Intersection|intersections]] | Taking the [[General Setwise Operations#Union|union]] (val) of six piece-specific [[General Setwise Operations#Rotate|rotates]] (left by 1..6) of six piece disjoint [[General Setwise Operations#Intersection|intersections]] | ||
for the absolute difference of the [[BitScan#TrailingZeroCount|trailing zero counts]] of that union and the passed square bitboard (pos) is a bit too much calculation for that purpose <ref>[https://github.com/BarrySW19/CalculonX/blob/master/src/main/java/barrysw19/calculon/engine/BitBoard.java#L418 CalculonX/BitBoard.java at master · BarrySW19/CalculonX · GitHub]</ref>. | for the absolute difference of the [[BitScan#TrailingZeroCount|trailing zero counts]] of that union and the passed square bitboard (pos) is a bit too much calculation for that purpose <ref>[https://github.com/BarrySW19/CalculonX/blob/master/src/main/java/barrysw19/calculon/engine/BitBoard.java#L418 CalculonX/BitBoard.java at master · BarrySW19/CalculonX · GitHub]</ref>. | ||
Revision as of 21:57, 23 February 2020
Calculon,
a Java chess engine by Barry Smith named after the Futurama character.
It is open source, licensed under the Apache License, Version 2.0 and hosted at GitHub [2].
Calculon is UCI compatible, uses bitboards as basic data structure, and applies Negamax alpha-beta. The engine regularly plays on ICC under the name CalculonX and has Blitz/Standard ratings there around the 1750 mark.
getPiece
Calculon's getPiece routine to get a the piece code of a square (the least significant one-bit of the passed bitboard pos, typically single populated) from the six piece bitboards of its board representation is an idiosyncratic sample in avoiding a redundant 8x8 board as well in avoiding branches. Taking the union (val) of six piece-specific rotates (left by 1..6) of six piece disjoint intersections for the absolute difference of the trailing zero counts of that union and the passed square bitboard (pos) is a bit too much calculation for that purpose [3].
public class BitBoard { // Position object
public byte getPiece(long pos) {
long val = Long.rotateLeft(bitmaps[MAP_PAWNS] & pos, MAP_PAWNS)
| Long.rotateLeft(bitmaps[MAP_KNIGHTS] & pos, MAP_KNIGHTS)
| Long.rotateLeft(bitmaps[MAP_BISHOPS] & pos, MAP_BISHOPS)
| Long.rotateLeft(bitmaps[MAP_ROOKS] & pos, MAP_ROOKS)
| Long.rotateLeft(bitmaps[MAP_QUEENS] & pos, MAP_QUEENS)
| Long.rotateLeft(bitmaps[MAP_KINGS] & pos, MAP_KINGS);
if(val == 0) {
return Piece.EMPTY;
}
return (byte) ((Long.numberOfTrailingZeros(val) - Long.numberOfTrailingZeros(pos)) & 0x07);
}
}
External Links
Chess Engine
Misc
- Calculon - Futurama Wiki, the Futurama database
- Calculon 2.0 - Futurama Wiki, the Futurama database
- Calculon - The Infosphere, the Futurama Wiki
- Calculon (All My Circuits) - The Infosphere, the Futurama Wiki
- Calculon (Character) - IMDb - Movies, TV and Celebrities
- Calculon 2.0 from Wikipedia
