Author: Robert Hyatt
Date: 06:58:05 09/16/04
Go up one level in this thread
On September 16, 2004 at 09:49:40, Jon Dart wrote: >On September 16, 2004 at 08:31:12, Robert Hyatt wrote: > > >> >>4 plies into the tree 2-fold repetition should be scored the same as a 3-fold >>repetition to avoid this. This also points out that the program would have a >>problem with repetition detection if it can only see a 2-fold repetition but not >>the 3rd, letting it overlook a forced draw it might want to avoid or accept >>depending on game circumstances... > >I will check this out and consider the fix you suggest, but I am not sure there >is the more general problem .. as the PV indicates I believe here it can and >would avoid a 3rd repetition. It certainly knows a 3rd repetition is a draw and >will score it as such. > >--Jon Set up a position with black king at a8, white rooks at g7-h7 with enough material on the board for black so that white wants the draw. See if white will play the obvious perpetual along the rank, noting that it is pretty deep to the third repetition as the king can walk back and forth across the board two full times before a repetition. What I do was suggested by John Stanback many years ago. I don't count 2-fold repetitions as draws for the first two plies only. At plies 3 and beyond, 2-fold repetitions get scored as a draw, but at plies 1-2, it takes the full 3 repetitions. This solves the above problem easily, while still not claiming draws at ply=1 until it is really a draw...
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