Author: Vincent Diepeveen
Date: 05:33:10 02/01/00
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On February 01, 2000 at 05:55:39, Tijs van Dam wrote: i have a special function doing the first ply for me. i have a special variable there to store the move diep is gonna play. the rest i get out of the hashtables. note that i use 8 probe and depth replacement, so it's very unlikely that the root move is not equal to the move in the hashtable. >On January 31, 2000 at 19:42:37, Vincent Diepeveen wrote: > >>On January 31, 2000 at 16:48:41, Tim wrote: >> >>>Crafty does not use(store and probe) hash table at root. >>>How about other programs? >>>Is there problem to use hash table at root? >> >>It depends upon how you write to hashtable, >>but in general spoken it is not possible. >> >>Suppose you get to the same position as the root position somewhre in >>your lines, which is very likely. now suppose one day that's with >>difference alfa and beta values, so even though you already have it >>in the hashtable you might overwrite it with a small depth, say 1 ply. >> >>then you need to abort your search. searching PV of this ply is not ready >>yet. In your hashtable is only a 1 ply search from this position. >> >>Bad luck. all those plies searched for nothing... > >I don't understand fully what you mean. Do you, after a search, extract the PV >from the hashtable? Then i see your point. But I save the PV when getting a >value between alpha and beta anywhere in the search. The problem you are >referring to gives me a 1 ply search hash value for the position, while >otherwise I would have none at all. So when I have this position again, at least >I have a 1-ply-best move to search first. > >Tijs
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