Author: martin fierz
Date: 01:40:34 02/12/04
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On February 12, 2004 at 04:23:54, Tord Romstad wrote: >On February 11, 2004 at 16:43:06, martin fierz wrote: > >>on my long todo list for my program, the item "pawn hashing" has slowly but >>steadily floated upwards. now it's on top. so: how large is your pawn hashtable >>(in # of entries)? how large are your entries? i'm using bitboards, and it seems >>to me that my entries will be huge, e.g. if i want to save some simple stuff >>like >> >>- passers >>- connected passers >>- isolated pawns >>- doubled pawns >>- backward pawns >>- blocked pawns >> >>that would be 6x8 = 48 bytes; perhaps times 2 for each side (or i could pop >>black and white pawns in the same bitboard, and & it with the black/white >>bitboard to save space). still, that's already 48 bytes and i guess i could save >>some more stuff if i thought about it a bit longer :-) >>is that a reasonable size for a pawn hash entry? hi tord, thanks for your answer! >My entries are much bigger; currently 128 bytes. I store all of the above, >as well as information like total number of pawns on black/white >squares for each side, total number of blocked pawns on black/white squares, >weak squares, open files, pawn storm stuff for use in positions with >castling to opposite sides, and a classification of the central pawn >structure. yes, obviously one can store lots of stuff. i also have some code on most of your topics above in my engine, but i forgot when i wrote my post :-) i can think of many other things too. and thanks to your information... > >In my opinion, there is no reason to be afraid of having big pawn hash >table entries, because you need very few of them. The pawn structure >doesn't change that often. I've found that 256 entries is enough in >my engine. Making the table bigger gives only a tiny speedup. ... that even 256 entries are enough, i won't mind putting all that stuff in! thanks for sharing. cheers martin
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