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Exploding Bitboards

272 bytes added, 14:53, 18 May 2018
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'''[[Main Page|Home]] * [[Board Representation]] * [[Bitboards]] * [[Sliding Piece Attacks]] * Exploding Bitboards'''
[[FILE:NTS - BEEF - WATUSI.jpg|border|right|thumb|[https://en.wikipedia.org/wiki/Nevada_Test_Site#Area_4 Nevada Test Site - Big Explosives Experimental Facility] (BEEF) <ref>[https://en.wikipedia.org/wiki/Explosion Explosion from Wikipedia]</ref> ]] The expanding or '''exploding bitboards''' were created by [[Harald Lüßen]] with some help from other people in [[CCC]] <ref>[http://www.open-aurec.com/wbforum/viewtopic.php?f=4&t=4523&start=80 Re: Compact Bitboard Attacks] by [[Harald Lüßen]], [[Computer Chess Forums|Winboard Forum]], September 13, 2006</ref> . The idea is to generate the attacks of a sliding piece from its square outside on all its rays in parallel like the waves of a stone thrown into water. This is done in some steps with multiplications and shifts like in the [[Kindergarten Bitboards|kindergarten bitboards]]. At each step or distance from the original square the rays can be expanded or stopped by other pieces from an occupied bitboard. There are some nasty overflow problems at the border of the board that must be solved. This approach is slower than other techniques. The code below is taken from the chess engine [[Elephant]] which is known for some bitboard comparisons but not for [[Playing Strength|playing strength]].
In the example this [[Square Mapping Considerations|big-endian file-mapping]] is used:

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