Author: Robert Hyatt
Date: 14:04:27 06/03/98
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On June 03, 1998 at 06:28:41, Alessandro Damiani wrote: >On June 02, 1998 at 06:49:16, Inmann Werner wrote: > >>Hello! >> >>Making programs faster is making them playing better.(?!) >>OK >>But in a match, if there is a time limit, it is important, that the >>program thinks long at the right time, and not, when everything is >>clear. >>But to implement that is more then difficult. When is a move "clear"? >>Maybe deeper, there is a fine combination. When should the program >>take time to look deeper? >> >>any suggestion, which are common? > >Hi Werner! > >One idea I had some days ago was to use the definition of singularity at >the root to decide whether to start the next iteration or not: > >If the best move is at least S better than all other moves, then stop >the search. Since we know the score of the best move, the cost is >testing the siblings with a null-window. > >So, when one move is obviously better than the others, the program will >stop and play that move. Seems ok to me. But: is the cost worth it or >not? I think not, but perhaps I am wrong? > >Ciao > >Alessandro this will make you look like a genius at times, and a fool at other times. Here is a sample position: 5r1k/6p/1n2Q2p/4p//7P/PP4PK/R1B1q/ w This is from the game Cray Blitz vs Belle, at the 1981 ACM event. This has shown up in more than one "test suite" position. At this tournament, we were running in a "batch processing backup system" with no thinking on the opponent's time or anything. I had to submit a batch job, and then keep checking to see when it finished. We were using about 30-45 seconds per move because the machine was not dedicated (this was a backup machine as our primary machine had died). Here's the gist: at short searches, Qxb6 seems to win material. If you notice this and use your idea to notice that this move is way better than any other move at the root, you can quit the search early and make a really silly mistake, because you can win a piece, but get killed in the process. In this game, Cray Blitz actually played Qxb6 and lost. Crafty finds that Qb6 is bad and finds the forced draw (Bxh6) in just a few seconds. But if it quit because it thought that Qxb6 was far better than all the other moves (root singular) it would be "surprised..."
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