Author: Robert Hyatt
Date: 06:55:48 08/12/04
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On August 11, 2004 at 04:29:35, Tord Romstad wrote: >On August 10, 2004 at 23:41:46, Stuart Cracraft wrote: > >>This repy from Bob Hyatt to Alessandro 5 years ago >>seems the best explanation so far. Anything to add >>anyone? Implementation gotchas? >> >>Mine is (roughly) and untested until the ovenright run: >> >> quiesce >> : >> baseval = eval(); >> : >> while next capture move available >> if (value_of_captured_piece + (2*maxpositionalscoresofar) + baseval >> < alpha) >> continue; >> else >> makemove >> see or mvv/pva, etc. >> decide whether to search further >> unmakemove >> fi >> endloop >> : >> : > >"Delta pruning" was a new name to me. The above looks exactly like what >is usually called futility pruning. The pseudo code above looks OK, but >there is one simple improvement: In addition to the value of the >captured piece, you also add the change in piece square table score. > >Tord Futility is what it is. The name "delta pruning" was something coined by someone after looking at the Crafty source and noticing I use the variable name "delta". :)
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