Author: Alessandro Damiani
Date: 15:01:30 09/11/99
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On September 11, 1999 at 17:58:59, James Robertson wrote: >On September 11, 1999 at 17:54:55, Alessandro Damiani wrote: > >>On September 11, 1999 at 15:56:10, Ed Schröder wrote: >> >>>On September 11, 1999 at 15:42:03, Robert Hyatt wrote: >>> >>>>On September 11, 1999 at 11:42:29, Ed Schröder wrote: >>>> >>>>>>Posted by Robert Hyatt on September 11, 1999 at 10:19:19: >>>>>> >>>>>>In Reply to: Re: Interesting mate test for hashing posted by Ed Schröder on >>>>>>September 11, 1999 at 01:43:12: >>>>>> >>>>>>On September 11, 1999 at 01:43:12, Ed Schröder wrote: >>>>>> >>>>>>> >>>>>>>Do not underestimate the idea that in case there is no bestmove from the >>>>>>>hash table you do a full static evaluation of all nodes first and based >>>>>>>on that you pick the bestmove as being the first move you are going to >>>>>>>search for this (new) depth. The very early Rebel's (1981) worked that >>>>>>>way and I remember (although the system is very time consuming) it was >>>>>>>superior to all other systems I tried. >>>>>>> >>>>>> >>>>>>I'm not underestimating it. I was simply saying that this approach can >>>>>>be applied when the position is encountered and there is no 'best move' >>>>>>in the hash table. Rather than doing it when the hash entry is stored, >>>>>>and we are not even sure that this hash entry will ever be used again or >>>>>>that it won't be overwritten before it is needed. >>>>> >>>>>Right. >>>>> >>>>>>>I later removed the system because hash tables + bestmove was more powerful >>>>>>>at least for Rebel. But I wouldn't exclude the possibility such a system >>>>>>>can have a positive effect on the speed of the search. >>>>>>> >>>>>>>Actually I didn't remove the system but I replaced it with a faster one >>>>>>>that is: >>>>>>> >>>>>>>- generate all legal moves; >>>>>>>- for all moves do a (very) quick evaluation; >>>>>>>- sort all moves based on the quick evaluation. >>>>>>> >>>>>>>This (move ordering) system (for Rebel) is still superior. >>>>>>> >>>>>>>Ed >>>>>> >>>>>> >>>>>>Do you use killers, history, etc? >>>>> >>>>>Just the normal stuff. >>>>> >>>>>Order... >>>>> >>>>>- hash table move >>>>>- winning captures (ordered by expected material gain) >>>>>- promotion >>>>>- equal captures (QxQ etc) >>>>>- killers (4 of them) >>>>>- remaining moves ordered by the intelligent move generator >>>>> >>>>>The Killer History from Jonathan Schaefer gave no improvement for me. >>>>> >>>>>Ed >>>> >>>> >>>>It probably won't help if you keep 4 killers. I didn't find any improvement >>>>in Cray Blitz either... but I did even more with killers. I tried the current >>>>ply killers then the killers from _other_ plies if they were legal... adding >>>>history did nothing for me... I probably ought to re-check Crafty again as it >>>>might be extra overhead for nothing now... >>> >>>I use 2 killers from the current ply (that's the normal way) and the 2 from >>>2 plies back. The latter gave me 5%. >>> >>>Ed >> >>I am surprised: history doesn't help? I think that the static ordering is good >>enough then. Perhaps history is good for those with a bad static ordering, like >>me? >> >>Alessandro > >History didn't help me at all either. I just ended up with a lot lower NPS.... > >James Am I the last one with history heuristic here? :-) Alessandro
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