Author: Robert Hyatt
Date: 14:00:14 08/06/99
Go up one level in this thread
On August 06, 1999 at 15:59:32, Dave Gomboc wrote: >On August 06, 1999 at 13:48:17, Robert Hyatt wrote: > >>On August 06, 1999 at 11:27:26, Pete R. wrote: >> >>>On August 06, 1999 at 08:51:20, Robert Hyatt wrote: >>> >>>>On August 06, 1999 at 00:33:02, Terry Ripple wrote: >>>> >>>>> I sometimes see accesses from a total of 7 to 9 pieces still on the board and >>>>>was wondering how accurate it`s analysis of the evaluation is and is the >>>>>analysis more accurate when it shows alot more accesses like several thousand >>>>>compared to 10 to 100 accesses or don`t this matter, as long as it`s showing >>>>>that it reached the endgame tablebases? Please note that i only installed the >>>>>four man tablebases in my Hiarcs7.32! >>>>> I`am using a AMD K6-2/266Mhz with 64 RAM and when playing games other than >>>>>blitz,i set the hashtables to 44.032KB. >>>>> >>>>>Thankyou in advance for any information, >>>>>Regards,Terry >>>> >>>> >>>>Think about it like this. At that stage of the game, your engine is probably >>>>searching at least 15 plies deep. For simplicity, think of the tree as a >>>>graph that is _exactly_ 15 plies deep along every line. With tablebase probes >>>>in the search, after any capture that takes the total pieces down to 4 or >>>>less, that branch goes no deeper and gets an _exact_ score at that point. >>>> >>>>However, your numbers are way off from what I see. I typically see the first >>>>EGTB hits (crafty, using 3-4-5 piece files) with 14-15 pieces still on the >>>>board (at blitz-type time controls). Hiarcs might be more conservative on how >>>>deep it can probe than Crafty is, I am not sure. But it makes a significant >>>>difference in the right positions... >>> >>>I just bought Hiarcs 7.32 the other day. The GUI is the same as Fritz, the big >>>difference is the tablebase access, and the really cool thing is that Crafty can >>>access the tablebases now within the GUI as well. I tested both Hiarcs and >>>Crafty on a position with about 8 or 9 pieces, and while they both hit the >>>tablebases I noticed that Crafty did so *much* more than Hiarcs, almost by a >>>factor of 10 as I recall. >> >>Probably the author was being conservative, not believing that you can really >>probe anywhere inside the 'basic search' without slowing down too much. It is >>easy to limit the max depth that the search will probe at, but this also >>limits the benefit... >>\ > >It might be because Hiarcs is probing from within an interior node recognizer >and Crafty is probing only at tips. Or does Crafty also probe at interior >nodes? > >Dave Crafty probes at _any_ node (not in the q-search however as that is way too slow) where the number of pieces drops to 5 or less. Interior or leaf nodes doesn't matter...
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