Author: Willie Wood
Date: 10:51:12 12/17/97
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On December 16, 1997 at 21:58:39, Dan Homan wrote: >I tried adding aspiration on top of >PVS, but >that seemed to add significant complication for little gain. Move >ordering >is hash moves, followed by captures, followed by history moves. I tried >adding >killer moves but this didn't seem to add much improvement over history >(perhaps I did something wrong). > I also took out my aspiration stuff, thinking it didn't add much. The killer moves, as I understand it, are really a subset of the history table, so it may not add much to use them in combination. I'm using only killer moves now, which really cuts the tree down in deeper searches. I will have a very good case for comparison, since in the next few weeks I'll be replacing killers with history as an experiment. BTW, have you tried eliminating the captures from your move-ordering? Theoretically, I'd think you'd get more cutoffs if you did. >The only forward pruning is by recursive null move. I recently >understood >something Bob Hyatt and Bruce Moreland had mentioned on occasion >about allowing the null-move to collaspe straight into the capture >search. >I implemented this (it turned out to be a simplification over what I was >doing >before) and it was a big win. Aha. I wonder if this idea is in the '93 Donniger article, or is it an enhancement? >The capture search considers only captures that will bring the score >above >alpha - no checks are considered. I recently extended the quiesence to include checks to the extent that checks occur in the full-width search. This is an attempt to reduce horizon. It does slow it down, but seems to have improved it. Is your program playing on ICC or just fics? I'd like to play it a couple of games. WW
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