Author: Michael Henderson
Date: 13:59:51 09/23/04
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On September 23, 2004 at 16:14:23, Stan Arts wrote: >>Can you invalidate entries in the hash table when a capture is made on the >>board? > >I thought of that, but that's quite drastic. Also thought of figuring out which >hashtable-entries are "affected" by this capture and adjust their scores for >the new move. But it would probably take some computing-power at the beginning >of a new move or end of last or whenever I'd want to do that hashtable- >adjusting, because it doesn't seem so easy to figure out which hashtable entries >to adjust without generating the positions somehow. Or I'd >have to add knowledge about this when reading back scores from the hashtable, >with path-information. Hmm.. Ok I'm just guessing here.. After you make a capture move on the board, creating critical situation: beta entry in hash table from search (before capture moves): val >= beta, with penalty assigned due to trading pieces. Then (val >= beta) will be true in future searches because val will actually be higher now. The position looks better *here* compared to the new root position that it did to the old root position. So I think your beta entries are fine. alpha entries you may have to adjust: for example, if you get alpha flag and val=120, the value may actually be val <= 130 or something now. so you may have to raise the value for the alpha entry by some margin to encompass the varying values. EXACT entries: you can make them bounded entries, using some margin. Or you can clear them. Of course, I could be wrong, but I thought it might help. Michael
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