Author: Martin Giepmans
Date: 09:12:55 08/10/01
Go up one level in this thread
On August 10, 2001 at 10:30:59, Tony Werten wrote: >On August 09, 2001 at 06:12:52, Martin Giepmans wrote: > >>On August 09, 2001 at 02:39:53, Bruce Moreland wrote: >> >>>On August 08, 2001 at 19:17:47, Martin Giepmans wrote: >>> >>>>On August 08, 2001 at 17:18:02, Bruce Moreland wrote: >>>> >>>>>On August 08, 2001 at 16:43:39, Martin Giepmans wrote: >>>>> >>>>>>Yes, I see your point. Now the question is: is there always pollution? >>>>>>I think 2 conditions are necessary: >>>>>>(1) The score (+0.20) is influenced by a drawscore that is based on *external* >>>>>>repetition. >>>>>>(There is no problem with the influence of internal repetition) >>>>> >>>>>No, this is false. You can get to the same position at the same depth in the >>>>>same iteration, and have subsequent moves with different repetition >>>>>consequences. >>>>> >>>>I don't see how this could have a negative effect, if you do not use cutoffs >>>>based on drawscores from the hashtable. >>> >>>Everything I have said in my posts in this thread is an attempt to show that >>>draw scores that you encounter influence other scores. >>> >>>bruce >> >> >>I understand what you are trying to say. Let's illustrate it with a (simplistic) >>example: >>Path A: 1. Nf3 Nf6 2. d4 d5 >>Path B: 1. d4 d5 2. Nf3 Nf6 >>Same position (P). > > >Suppose these moves happen a little later in the game. > >After whites first move, it could have been a draw in A because of a 50 move >rule, but not in B. > >cheers, > >Tony The positions after 1. Nf3 and 1. d4 are different, so there is no problem if the one is a draw and the other is not. But sure, the 50-moves rule can give problems with hashing: Play 98 reversible halfmoves (no pawnmoves, etc) from position P and you have a position that is a draw along path B and not along path A ... cheers, Martin > >>The program first takes path A and discovers that Ng1 is the best move in P >>(you need a weird static eval for that, but ok), score +0.40. >>Now the program takes path B. Is Ng1 the best move? No, black plays Ng8 >>and repeats the position after d4 d5. Score 0.00. >>The best move is, say, Nc3. Score +0.10. >> >>I think this proves your point: drawscores influence other (nonzero) scores. >>However, along path B white has obviously not played the best moves. >>If white gets 0.10 instead of 0.40 there must be something wrong with either 2. >>Nf3 or 1. d4 or both. >>So, my question is: does this influence of drawscores minimax downto the root of >>the tree? My first thougth was no, my last (thought 31) is: I really don't know >>...
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