Author: Terry Ripple
Date: 10:35:09 08/06/99
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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... --------- Bob, I noticed that when there were hits in the tablebases earlier in its search and first showed only a hundred or so accesses with a particular score and best move so far in the position and leaving it continue in its search for a few more ply, the accesses increased dramatically to several thousand hits and the score plus evaluation of the position also changed which then appeared to be a better evaluation than early on, so if like you say that once the search starts hitting the tablebases and these hits are an exact score at this point, then why does the score and analysis of the position change as it progresses deeper into its search? I was under the impression that once you start getting hits to the tablebases, then that score and evaluation will be exact and won`t change its score of that position any longer, even if you let the analysis continue deeper because the endgame tablebases once reached are "exact". Help!!! Thanks alot for taking the time to explain this, Best regards, Terry
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