Author: Robert Hyatt
Date: 19:30:28 08/08/01
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On August 08, 2001 at 12:30:47, TEERAPONG TOVIRAT wrote: > >Hi, > >As I understand, a draw score from hashtable can be originated from >1.an almost equal position 2.repetition of position >Is it generally recommended to differentiate these 2 conditions? >How much would I gain if I fix the problem? > >Thanks, >Teerapong The above doesn't quite read right. If you hash _everything_ (EP status, castling status, etc) then you can't get "almost" matches. But the problem is that the drawscore might not be "right". IE the hash entry says "this is a draw, assuming you can search from this position to the drawn position with no problems." If you treat two-fold and three-fold draws differently, this can break. However, in counterpoint, other scores are _also_ wrong for the same reason. A normal hash score says "if I search from this position to the terminal position that produced this score, I will get this score." But it doesn't realize that it is more than possible that before you reach that terminal position, you cross over a repetition position or a 50-move rule counter violation, or something similar... So that you think you might be winning, but are heading for a forced (and unseen) draw. I ignore the problem myself and store draw scores without a second thought.
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