HeavyChess

**[[Home]] * [[Engines]] * HeavyChess**
|| [[image:HeavyChess.jpg link="http://www.flickr.com/photos/teosaurio/4531534307/in/photostream/"]] ||~ || **HeavyChess**,
an [[UCI]] compliant [[Open Source Engines|open source chess engine]] written by [[Chispa]] author [[Federico Andrés Corigliano]] in [[Cpp|C++]], released in 2007 <ref>[[http://www.open-aurec.com/wbforum/viewtopic.php?f=2&t=49475|HeavyChess]] by [[Ron Murawski]], [[Computer Chess Forums|Winboard Forum]], September 09, 2008</ref>. ||
|| Heavy Chess <ref>[[Chessboard|Chessboard]] and [[Pieces|pieces]] made out of [[http://en.wikipedia.org/wiki/Mining|mining]] tools and parts in [[http://en.wikipedia.org/wiki/Cerro_Sombrero|Cerro Sombrero]], [[http://en.wikipedia.org/wiki/Chile|Chile]]. [[http://www.flickr.com/photos/teosaurio/4531534307/in/photostream/|Flickr Photo]] by [[http://www.flickr.com/photos/teosaurio/|Mr. Hicks]], March 08, 2010</ref> ||~ ||^ ||
[[toc]]
=Description=
==Board Representation==
HeavyChess is a [[Bitboards|bitboard]] engine and uses compact [[Rotated Bitboards|rotated bitboards]] to determine [[Sliding Piece Attacks|sliding piece attacks]]. It performs eight [[Population Count#Lookup|byte lookups]] to [[Population Count|count populations]], and [[#BitScan]][[BitScan|bitscan]] by conditional 64k lookups, where the most significant bit on the chess board maps the least significant arithmetical one <ref>HeavyChess 0.13 \BitBoards.h</ref>:
[[code format="cpp"]]
// Devuelve el Most Significant Bit de un Bitboard
inline Casilla Bitboards::MSB(const Bitboard &b) {
   if (b&65535) return static_cast<Casilla>(TablaMSB[b&65535]);
   if (b&MSBMask1) return static_cast<Casilla>(TablaMSB[(b>>16)&65535]+16);
   if (b&MSBMask2) return static_cast<Casilla>(TablaMSB[(b>>32)&65535]+32);
   return static_cast<Casilla>(TablaMSB[b>>48]+48);
}
[[code]]
==Search==
HeavyChess applies [[Principal Variation Search|PVS]] [[Alpha-Beta|alpha-beta]] with [[Transposition Table|transposition table]] and [[Null Move Pruning|null move pruning]], [[Mate Threat Extensions|mate theat]] and [[Check Extensions|check extensions]] inside a [[Depth#FractionalPlies|fractional ply]] [[Iterative Deepening|iterative deepening]] framework with [[Aspiration Windows|aspiration windows]].

==Evaluation==
The [[Evaluation|evaluation]] seems not that heavy as the program's name suggests. Beside obligatory, [[Incremental Updates|incremental updated]] [[Material#Balance|material balance]], HeavyChess utilizes [[Piece-Square Tables|piece-square tables]] and considers various piece terms, such as [[Bishop Pair|bishop pair]], [[Rook on Open File|rook on (half) open file]], and [[Rook On Seventh |rook on 7th rank]].

=See also=
* [[Chispa]]

=Forum Posts=
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=2&t=49475|HeavyChess]] by [[Ron Murawski]], [[Computer Chess Forums|Winboard Forum]], September 09, 2008
* [[http://www.talkchess.com/forum/viewtopic.php?t=29307|Heavychess]] by Mark Mason, [[CCC]], August 09, 2009

=External Links=
* [[http://www.oocities.org/ar/fedecorigliano/ajedrez/heavychess/|Index of /fedecorigliano/ajedrez/heavychess]]
* [[http://kirr.homeunix.org/chess/engines/Norbert%27s%20collection/HeavyChess%200.13%20beta/HeavyChess/|Index of /chess/engines/Norbert's collection/HeavyChess 0.13 beta/HeavyChess]] by [[Norbert Raimund Leisner]], hosted by [[Kirill Kryukov]]
* [[http://www.computerchess.org.uk/ccrl/404/cgi/engine_details.cgi?print=Details&eng=HeavyChess+0.13+beta|HeavyChess 0.13 beta]] in [[CCRL|CCRL 40/4]]

=References= 
<references />
=What links here?= 
[[include page="HeavyChess" component="backlinks" limit="20"]]
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