Author: Robert Hyatt
Date: 07:46:49 01/11/98
Go up one level in this thread
On January 11, 1998 at 10:45:20, Robert Hyatt wrote: >On January 11, 1998 at 08:51:06, Carsten Kossendey wrote: > >>On January 11, 1998 at 01:07:46, Stuart Cracraft wrote: >> >>>Someone on this newsgroup wrote about a useful extension >>>that went something like "If the null move search returns >>>a mate score, e.g. n moves to mate, then extend." >> >>If you use recursive null moves, you will want to limit it to small N's >>since otherwise you start extending lines where your opponent moves 6 >>times in a row or something, and even the most quiet positions look like >>mates then ;) >> > >I do recursive null-move, but *never* two null-moves back to back, so >that >this isn't a problem. For me, turning this on (plus the hashing >enhancement >I described after Bruce explained his basic idea) means Crafty now finds >Win At Chess 141 in under 30 seconds. This position has eluded solution >(by Crafty) for a couple of years. > >In one minute per move, I now only miss 2 on a P6/200... number 160 and >number 230. 160 still takes 4 minutes or so, while 230 I don't know. >The >good news (for me) is that Crafty is now approaching Cray Blitz in >tactical >skill *if* hardware is equal. Cray Blitz still solves 297 in less than >1 >second, and gets all 300 in 1 second or less (it only times to the >nearest >second, so a 1 second limit really means up to 1.5 seconds per position >or >so. Crafty can do all but 2 in 60 secs at 100K nodes per second. Based >on Cray Blitz's speed of 5M nodes per second on a 2ns T90, Crafty should >be able to hit around 10M nodes per second, or be about 100X faster than >it is now. That would put it solving all but 2 in under 1 second. >null-move >R=2 seems to affect 230, because the first move tosses a rook, and >null-move >searches below that tend to fail high... > > >>>I didn't see any improvement (with limited testing) after >>>implementing this. Is it basically in time-to-solve or >>>seeing more solutions? >>> >>>Where's the beef? >>> >>>--Stuart I knew that sounded wrong. the only two Crafty misses in 1 minute are wac163 and wac230... *not* wac160. that one is easy...
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.