Author: blass uri
Date: 03:14:47 12/25/98
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On December 24, 1998 at 19:03:00, Robert Hyatt wrote: >On December 24, 1998 at 11:02:09, blass uri wrote: > >> >>On December 24, 1998 at 10:52:40, blass uri wrote: >> >>> >>>Suppose you do a brute force search to depth x then what is the longest lines >>>that you may search? >> >>I mean seeing everything for x plies when I say depth x. >> >>Uri >> >> >> >> >> >>> >>>I understood that for Junior the longest line is at most 4x and for crafty the >>>longest line is at most 2x. >>> >>>correct me if I am wrong >>> >>>What is the longest line for other engines > >first you have to have a common "depth" term. The depth junior displays is >_not_ the same depth the rest of us display, so you can't compare that. I understand and this is the reason that I explained that I mean seeing everything for x plies(it should be almost everything because Junior cannot see underpromorions so it cannot be everything but in more than 99% of the cases the result is the same as the result when it considers everything). If Junior displays depth 2x then I say because of this reason that the depth is only x. > >But in the case of Crafty, the nominal depth of search has nothing to do with >the number of moves in the PV. IE with a 10 ply search I can hit ply=50 at >times if the extensions get triggered just right. Someone posted a position >months ago that was a mate in 30, that Crafty found with a fairly shallow >(10 plies or so) search, yet it went a full 60 plies deep. This position was >one of the "rebel" positions where there was a contest to construct the deepest >mate with the fewest nodes... The question is what is the maximal plies that you can hit with a 10 ply search if you do not consider forced moves(only one legal move) and replies to forced moves. > >But when you see 10 plies, you do know that the pv was searched to at least 10 >plies, but could possibly have went to 50 plies (or more) along some variations. >Also you know that other non-PV moves may well have not even been searched to >10 plies thanks to the null-move... The question is what is the probability in practical games that you miss something important because of the null move. In other words suppose that you are not using null moves then what is the probabilty that you do a different move with a 10 ply search? Uri
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