Author: Dieter Buerssner
Date: 12:35:55 07/29/02
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On July 29, 2002 at 12:56:33, J. Wesley Cleveland wrote: >Let me give an example. Assume that while searching at a given ply, alpha is >1805 centipawns. When searching after a move for black, the hash table has a >lower bound of MATE-300 but the draft is less than the depth. Why would you not >want to cut off without searching here ? Wouldn't you search *exactly* the same >moves (assuming no hash table overwrites), and return the same MATE-300 value ? I do almost exactly this in Yace for mate bounds. Additionally I also use exact mate scores for cutoff, even when the draft is not enough, and when alpha or beta are not mate scores. I think, there are no problems with this method. Probably one has to take care, that no possibly wrong mate scores come from some null move search. BTW. I also handle mate bounds like exact mate scores - adjust them when storing in the HT, and readjusting when take them out. I never have seen a too short mate score at the root (which I would consider a bug), and in cases, where the shortest mate should be found due to the search depth, Yace allways found it, in the cases I checked. Regards, Dieter
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