Author: Heiner Marxen
Date: 11:21:36 07/14/99
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On July 14, 1999 at 03:33:03, blass uri wrote: > >On July 14, 1999 at 03:19:57, Shep wrote: > >>On July 14, 1999 at 01:05:25, Terry Ripple wrote: >> >>>On July 13, 1999 at 23:42:00, Brett Clark wrote: >>> >>>>On July 13, 1999 at 17:30:10, John Wentworth wrote: >>>> >>>>>I have had some games where Hiarcs will first announce mate in 3, then on >>>>>it's >>>>>next move it announces mate in 5, then back to 3, back up to 6 etc etc. I >>>>>thought when it announced a mate in X number of moves, the moves were >>>>>forced. >>>>>Doesn't appear that way though. Has anyone else had this problem of am I >>>>>interpreting it wrong? >>>> >>>> >>>>I've had the same problem. Once, it announced mate in 9, then on the >>>>opponent's >>>>next move, it came back with an eval. of about +8.50 with no mate >>>>announcement. >>> >>>------- >>>In several of my computer vrs computer matches, i seen Hiarcs announce Mate7- >>>and this was 5-min. Blitz and was correct by its evaluation. I didn`t >>>experience >>>this problem that you are saying, as yet! >> >>Actually, this problem can be observed in quite a lot of chess programs >>(Junior, Fritz, Chess Tiger [rarely] etc.). >>Maybe it has something to do with null-move (?). > >Junior is not a null mover and crafty is a null mover so it has nothing to do >with null move. One reason may be incomplete endgame tables. When the winning line involves a promotion or capture, and the table for the resulting material is missing, the engine has to search it itself. That search can happen to not find the mate (here null move may make a difference). In this case any move which stays within the table and has a mate score is preferred over moves falling out of the table and not yielding a mate score. I remember Bob advising to always have all supplementary tables. This effect is a good reason to follow his advice (IMHO). Heiner >I do not think it happens very often to Junior. >It is more common with Fritz from my experience in engine-engine games. > >Uri
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