Author: Uri Blass
Date: 19:34:11 08/14/05
Go up one level in this thread
On August 14, 2005 at 21:29:50, Robert Hyatt wrote: >On August 14, 2005 at 20:08:21, Uri Blass wrote: > >>On August 14, 2005 at 18:01:28, Robert Hyatt wrote: >> >>>On August 14, 2005 at 17:00:02, Bernhard Bauer wrote: >>> >>>>On August 14, 2005 at 16:47:43, Darrel Briley wrote: >>>> >>>>>On August 14, 2005 at 15:22:43, Graham Banks wrote: >>>>> >>>>>>Best wishes for the remaining games. It would be really good for this to be the >>>>>>best Crafty ever! Fingers and toes crossed! >>>>>> >>>>>>Graham. >>>>> >>>>>1.5 with two blacks vs. Shredder and Junior. Impressive indeed. >>>>>Congratulations Bob! >>>>> >>>>> DB >>>> >>>>As Bob has pointed out earlier this is pure luck. >>>>Crafty has serios tactical weaknesses as all the >>>>computer chess specialists know. Crafty is not even commercial, >>>>so how can this be explainded in any other way, but luck? >>>>Perhaps Bob has found a very old version and is running this now, 6.4? >>>> >>>>Anyway congratulations and >>>>Kind regards >>>>Bernhard >>> >>> >>>I'd bet that those "serious tactical weaknesses" are not to be found on this >>>hardware, at least until someone is searching far faster than I am... >> >>Tactical weaknesses can be found also in software. > > >And they can be compensated for by fast hardware. > >> >>> >>>Crafty's "serious tactical weaknesses" are more urban legend than fact... >> >>Comparing Crafty with fruit Crafty does not do checks in the first ply of the >>qsearch when fruit does it and Crafty does not use history based pruning when >>fruit does it. > >So? What says checks in the first ply of q-search is better? Crafty early >versions prior to the Jakarta version did checks in the q-search. Any idea why >I might have stopped? Both Bruce and I (Ferret) decided after much testing that >it was no worse at all, and the extra search speed was actually beneficial... Interesting that other programmers found different things so maybe something was wrong in the implementation. I know that you used checks in the qsearch and stopped but the question is if you used it in the right conditions. > >forward pruning certainly introduces tactical problems more than it cures them. >Look at the Rxh6 game vs shredder the other night. Whredder somehow just >overlooked the hung pawn... I am not sure about what game you talk I see no possible Rxh5 in the games of shredder in this tournament. Note that in the case of fruit to be technically correct it is not exactly pruning but reduction and the idea is that moves that almost never failed high are searched with reduced depth if they are not in the top of the list and only if they fail high a research is done with the original depth. Uri
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