Author: Uri Blass
Date: 10:07:52 10/02/03
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On October 02, 2003 at 10:56:21, Tord Romstad wrote: >On October 02, 2003 at 08:09:41, Anthony Cozzie wrote: > >>On October 02, 2003 at 05:21:45, Tord Romstad wrote: >> >>>I have just finished a 100-game test match between a version of Gothmog with >>>the Botvinnik-Markoff extension and an identical version without the extension. >>>The version with the new extension added won by 56.5-43.5. >>> >>>Not enough data to make any definite conclusions, of course, but it certainly >>>looks interesting. >>> >>>Tord >> >>Could you post some positions where BM-Gothmog was able to outthink ordinary >>Gothmog? > >Unfortunately I haven't studied any of the games -- I just left the match >running overnight, and checked the result when I came back to my office >this morning. > >The only position I can offer you now is WAC141, which is solved in >8 plies (about 6 seconds) without the extension, and in 7 plies (about >1.5 seconds) with the extension added. > >>Just offhand, it seems to me like this extension would extend a lot of >>useless things, but your result seems to indicate otherwise. > >It is not terribly expensive, at least not with my implementation (I only >extend when the threat is rather serious). In non-tactical positions, the >slowdown is hardly noticable. In tactical positions, I need about 10-20% >more nodes to search to the same search depth, but apparently this is >outweighed by the fact that a few tactical shots are seen one ply earlier. You implemented it very fast. I think about implementing it but it is not a trivial task. I understand that you use the move that comes after the null move to determine the target. The problem is that after undoing the null move I do not know the move that came after it in case of no moves after it and it is possible that the qsearch that came after it generated no move. I can determine a special varaible nodesnull and have nodesnull=nodes after null move and check if nodes>nodesnull after I undo null move and check for a threat only in case that nodes>nodesnull. I wonder if you did something similiar. Uri
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