Author: Daniel Shawul
Date: 02:37:17 05/05/04
Go up one level in this thread
On May 05, 2004 at 05:32:10, Tony Werten wrote: >On May 05, 2004 at 05:22:54, Daniel Shawul wrote: > >>On May 05, 2004 at 05:16:49, Uri Blass wrote: >> >>>On May 05, 2004 at 05:06:43, Daniel Shawul wrote: >>> >>>>On May 05, 2004 at 05:01:55, Uri Blass wrote: >>>> >>>>>On May 05, 2004 at 04:40:43, Andrew Williams wrote: >>>>> >>>>>>On May 05, 2004 at 03:03:15, Daniel Shawul wrote: >>>>>> >>>>>>>Hello >>>>>>> >>>>>>>Is incremental attack table slower than creating them on fly? >>>>>>>I have both versions working properly right now but the incremental >>>>>>>one further drops NPS by 30% , though InCheck and Checks are for free in this >>>>>>>case. Anybody have similar experience? I am sure i have made no mistake in >>>>>>>updating because i checked it with the known perft positions and node count is >>>>>>>perfect. >>>>>>> >>>>>>>best >>>>>>>daniel >>>>>> >>>>>>It's a very long time since I implemented them, but at the time I compared the >>>>>>incremental ones were faster. I can't remember exactly how much faster it was, >>>>>>but I think it was of the order of 10 to 15%, if only because that is what a >>>>>>comment in an old source file says. What I don't know is if this was *after* >>>>>>thorough debugging. >>>>>> >>>>>>Andrew >>>>> >>>>>I have different attack tables. >>>>> >>>>>Last time that I implemented incremental tables was a long time ago before I had >>>>>a chess program. >>>>> >>>>>I did not make notes to see how much faster it was but it was more than being >>>>>1000% faster in calculating perft. >>>>> >>>>>Uri >>>> >>>>How can incrementally updating attack tables make perft faster? >>> >>>I need the attack tables to generate legal moves. >>> >>>I have a function that generates the legal moves and it is dependent on the >>>tables. >>> >>>My tables tell me if a square is attacked by the opponent so I do not generate >>>moves that put the king in check. >> >> First you update the attack table with the move and then you generate only >>legal moves based on the attack tables , right? What i do is update the attack >>table and then generate "pseudo legal" moves,except king moves to an attacked >>square. So our difference is you have a routine which calculates only legal >>moves based on your attack tables. I don't see how that can speed up perft >>immensely. > >At the last ply you don't do make_move but just count the moves since you >already know they're legal. That's a nice trick to speed up perft.But why? It brings nothing to real search. And i want perft to be a model of my search. > >Tony > >> >>daniel >> >>> >>>My tables also tell me the directions that a square is attacked and the square >>>of the attacker from every direction so in case that the king is attacked I have >>>a special function to generate moves that is using this information. >>> >>>I never had move generator that is not dependent on the tables and makemove >>>always updated the tables. >>> >>>Uri
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