Changes

Gerardo Castano works as a medical doctor and writes computer chess programs as a hobby. Zeus 1.0 was written in [[Basic]] and finished fifth out of seven in the [[SCCC 1993|First Spanish Computer Chess Championship]] in 1993. The program was rewritten in [[C]] in 1994 and uses the standard techniques of [[Alpha-Beta|alpha-beta search]], [[Extensions|selective extensions]], [[Principal Variation Search|minimal PVS]], [[Transposition Table|transposition tables]], [[Killer Heuristic|killer heuristic]], [[History Heuristic|history heuristic]], [[Null Move Pruning|null-move pruning]] and [[Quiescence Search|quiescence search]]. [[Captures|Capturing moves]], [[Check|checks]], [[Promotions|promotions]], [[Threat Move|mate threats]] are all considered in the search. Zeus 2.0 used 256KB hash tables and searched 3000 [[Nodes per Second|nodes per second]]. It won the [[SCCC 1994|Second Spanish Computer Chess Championship]] in 1994 with a perfect score of 7/7. Zeus 3.0 uses massive [[Hash Table|hash tables]] (32MB), and contains extensive [[Knowledge|chess knowledge]] ([[Pawn Structure|pawn structure]], [[Square Control|strong squares]], [[Bad Bishop|bad bishop]] etc). The [[Opening Book|opening book]] contains about 300,000 positions and recognizes move and color [[Transposition|transpositions]]. The [[Endgame Tablebases|endgame database]] is being developed and the [[Evaluation|evaluation function]], although large, has thus far produced good results...