Author: Will Singleton
Date: 12:36:02 03/31/99
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On March 31, 1999 at 13:06:17, Bruce Moreland wrote: > >On March 31, 1999 at 12:46:42, Jeremiah Penery wrote: > >>On March 31, 1999 at 12:08:49, James Robertson wrote: >> >>>I have noticed from a post below that some people consider the position a draw >>>if it has repeated twice in the search. What are the advantages and >>>disadvantages of this? I am currently waiting until 3rd repetition; is this >>>worse? >>> >>>Thanks, >>>James >> >>From what I've seen, it's good to wait until the 3rd repetition. Very often, >>I've seen times when Crafty (which scores a draw at 2nd repetition) finds that >>it can force the position to repeat (for the second time) and so scores it as a >>draw, even when the opponent has any number of winning moves it can play before >>the third repetition. It often plays inferior moves thinking it can draw by >>repetition. >>I'm not sure where it could be better to detect draws after the second >>repetition - it seems it'd be just as easy, and more reliable, to detect them >>only at the third rep. > >My program was playing a game against Greg Kennedy a long time ago, and the >following situation occurred. > >The program was down two pawns and was completely lost. But Kennedy made a >mistake, and my program made a move that won a pawn. At this point the best >move from Kennedy's point of view was to undo the move he'd just done. My >program's move forced him off of something he was defending, and he had to go >back to where he was, and now the program could simply take a pawn that was >sitting there for free, vastly improve its chances for a draw. > >But that's not what it did. The move it made to win the pawn was also >retractable, so it chose to repeat the position, and scored this as 0.00. > >Of course, rather than repeating his mistake, Kennedy chose a better move and my >program was down two pawns again. > >bruce I've seen similar situations. My opponent makes a mistake, then I move, he then moves the piece back where it was (unusual), and I now repeat instead of taking advantage of the better situation. This can occur only when I want the draw, of course, and usually it's not harmful. But it could be. Is this worth fooling with? Will
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