Author: Robert Hyatt
Date: 06:35:09 09/30/04
Go up one level in this thread
On September 30, 2004 at 02:53:16, Stuart Cracraft wrote: >The null move killed, win-at-chess 141, has itself >finally been killed, vanquished with the help of >two board contributors whose combined suggestion >led to a 17-fold reduction in time-to-solve. > >This posting announces those winners. First the >stats! > >Now solved in 5.49 seconds on a P3 @ 1ghz it would be >solved in under 2 seconds on more modern equipment. >Formerly it took 95 seconds to solve. > >That's good enough for me. And it's good enough to win >the $50 contest posed recently since it broke the >10-second-and-under-barrieras posed in the contest >posting. > >The search: > >Alpha=-1332 Beta=-531 Maxdepth=9999999 MaxTime=99999 > 1/ 9 g2f1 0.00 -953 511 g2f1 f4d5 > g2f1 f4d5 > 2/ 9 g2f1 0.01 -953 884 > g2f1 f4d5 c1g5 > 3/12 g2f1 0.06 -953 11929 > g2f1 f4d5 c1g5 d5f6 > 4/16 g2f1 0.39 -953 72781 > g2f1 f4d5 b3d5 c6d5 f1g2 d6e7 > 5/24> g2f1 3.83 -552 978925 > g2f1 b5b4 b3a4 f4d5 f6g5 d5e7 > 5/25 c1f4 5.49 2260 1420038 c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 d7d >6 > c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 d7d >6 > 6/25 c1f4 6.06 2260 1519145 > c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 d7d >6 > >And with it the announcement -- because of the contribution >of Will Singleton in indicating that null move should be >avoided before leaves in the main search (and the sense >of a comparison in an old commented out section of the >code associated with disabled null move verification having been >intended to do what Will suggested but having been miscoded >by me and then #ifdefed out months ago) and Uri Blass' >comments about my recaptures being too free and easy, >the program went from a total of 95 seconds >for wac 141 to 5.49 after these two suggestions were >implemented. I doubt null-move is the problem. I do null-move _everywhere_ and Crafty has no problem solving wac 141 doing so... > >So Will and Uri are the winners, if they wish to accept, >of the divided $50 prize. Because Will's contribution was >more significant but less work for him and Uri's contribution >was less significant but with more work for him, but in either >case without the change from the other's suggestion the result >would not have been as dramatic getting down to <= 10 seconds >as stated in the earlier contest challenge a day or two ago, >the award has been divided in half for the 2 winners. > >Will and Uri are welcome to send me, and only if they wish >to collect, their postal mail addresses, to cracraft@cox.net >and a check for $25 will be sent out to each. > >In the future, more contests will be held like this whenever >I run into a huge roadblock but I see none looming presently, >including a rather unusual one that I am not ready to announce. > >Thanks everybody for the help on 141 -- and thanks to Will >Singleton and Uri Blass. > >Stuart
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