Author: Richard Pijl
Date: 01:30:18 06/17/02
Go up one level in this thread
<snipped> >>So you are basically using an always replace scheme. But it is inferior to the >>other scheme (replace only when new info is of better quality = bigger depth >>than the existing one). >> >>Why don't you use the better scheme? You are only one test away from it. >> >> >> >> Christophe > >The problem with replace only when the new information has bigger depth is that >it is possible that there is a node with a big depth that is not used. > >I also think that it is possible that some nodes are used often at small depth >with different order of moves that lead to the same position and not replacing >only because of some deep nodes may be a mistake. > >It is also obvious that if I do not clear the hash tables after every move >replace only when you have bigger depth is a mistake because you are going to be >left with old nodes that are not important and my first implementation of hash >tables was without clearing the hash tables. You could also 'age' the hashtables: Replace always when the hash entry was not inserted/referred to during this search, use another scheme when the hashentry was inserted during this search. This preserves results from previous iterations for move-ordering without ending up with only old entries. >I remember that I did not find clear advantage for replace only when the depth >is bigger but it may be also a result of other problems. A node with larger search depth costs more to reproduce. You'll need to probe an entry with a 2 ply shallower depth about 15 times as much before it's worth having the shallower one. Richard
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