Author: Tony Werten
Date: 00:59:50 10/02/04
Go up one level in this thread
On October 02, 2004 at 03:19:07, Gerd Isenberg wrote: >On October 02, 2004 at 02:14:32, Tony Werten wrote: > >>On October 01, 2004 at 19:41:24, Gerd Isenberg wrote: >> >>>On September 28, 2004 at 17:49:21, martin fierz wrote: >>> >>>>On September 27, 2004 at 17:27:45, Gerd Isenberg wrote: >>>> >>>>>On September 25, 2004 at 06:21:13, martin fierz wrote: >>>>> >>>Yes, Kogge-Stone and even more dumb7fill do often a lot of "stupid" work. >>>But 4 for 1 compensates that a bit. Depending on the design, one may profit from >>>the other parallel nature of fill-routines - to work setwise (not to mention >>>bitscanless). >>> >>>That becomes even more interesting if you feed up a set of safe target squares >>>of a sliding piece to get a set of progessive mobility - move targets in two >>>moves. >>> >> >>I was thinking about that. >> >>Generate safe squares for a piece, feed the resulting BB back to the generate >>squares and if the resulting BB does not differ very much from the first, the >>piece is locked up ? > >Yes, and this is a case, where one profits from disjoint directions as well, >even if it is most likely not so performance critical for a hashed evaluation >and considering alpha/beta bounds (lazy eval). > >E.g. for rooks, if you have disjoint vertical and horicontal attacks, it is only >neccessary to feed up vertical attack sets to horicontal filler and vice versa. > >Of course if safe capture targets are involved, one may ignore it or use one >additional fill in the same direction as the capture move. >I vote for "ignore". Safe captures are handled by (q)search anyway, a too >"pessimistic" evaluation of the capturing piece is probably not so important. Yes, I thought about cheating a bit as well. Safe squares are squares that have no pieces of me on them, and are not attacked by lower pieces ( I have them already calculated by then ) A safe capture would be a piece that is not defended by a lower piece. I might want to add the squares wich contain higher pieces, come to think of it. And remove squares that are attacked by higher pieces but not defended by me. Probably the best definition is: safe squares=squares not (attacked by lower pieces) and not (attacked by any piece and not(defended)) Don't think I'll be too far off then. Still a bit messy, but the point is that if you don't have any free squares with the optimistic view, you can give a large penalty. OTOH, you can also start with a pessimistic view, and only if that doesn't reach a certain amount, then start the expensive calculation. ie if my rook can move to 5 squares that are not attacked by you at all, there is no point in doing any calculation to decide on wether the squares you do attack might be safe. This might perform better in the endgame. Tony > >Gerd > >> >>Tony
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