Author: Uri Blass
Date: 07:19:48 03/12/02
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On March 12, 2002 at 09:40:41, Uri Blass wrote: >On March 12, 2002 at 08:40:28, Chessfun wrote: > >> >>What are the differences in Crafty 18.13 compared to 18.12? > >6 differences from Crafty's source code(I guess that 1 and 6 are the most >important changes): > >The following was copied from main.c in crafty source code and >I only edited it by adding a number for every change: > >1)Deep Blue extension limit removed and restored to one ply of >extension per ply of search. > >2)pruning in q-search fixed so that >a capture will be considered if it takes the total material on >the board down to a bishop or less for the opponent, as that can >greatly influence the evaluation with the EvaluateWinner() code. > >3)as the 50 move rule draws near, the hash table scores are marked >as invalid every 5 moves so that hashing can't hide potential >50-move-rule draws. > >4)lazy evaluation code modified to be more >conservative, since in endgames the positional score can be a >large change. > >5)EvaluatePassedPawnRaces() fixed so that if one >side has two pawns that are far enough apart, it will recognize >that even though the king is "in the square" of either, it can't >always stay in the square of one if it has to capture the other. > >6)pawn hash signature restored to 64 bits after testing proved that >32 was producing an unacceptable number of collisions. search >node counter is now 64 bits as well to avoid overflows. but in >the outside passed pawn code fixed (bad mask). > >Uri Correction: 6 is practically 3 changes so there are 8 changes. Uri
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