Author: Sven Reichard
Date: 01:57:59 06/25/02
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On June 24, 2002 at 11:54:55, Steve Coladonato wrote: >On June 24, 2002 at 07:39:35, Sven Reichard wrote: > >> >>IMHO it is apples vs. pears even on the same hardware. All programs use some >>sort of extensions and/or pruning, so the nominal depth is a rather artificial >>variable. >> >>Sven. > > >The nominal depth may be "artificial" because of the extensions and pruning but >would it not be a gauge of how well the alogrithms/heuristics are doing in the >evaluation? I understand from the other replies that Junior counts "plies" >differently, but do not the other programs use the term ply equivalently (I >don't know if that's a word or not)? I do know that if you chase an evaluation >down the variation the score can become much different near the end of the >variation. So would not a deeper ply depth also be an indicator for the >correctness of at least the initial part of the variation? > >Steve Let me give you an example. Two programs at some point search exactly the same tree, where some lines have depth 3, and others have depth 4. Program A says: This is depth 3, and I extended the interesting lines by one ply. Program B says: This is depth 4, and I pruned the hopeless lines by one ply. If they use the same evaluation function and have otherwise the same code, they are equally strong. However, it takes much longer for A to reach depth 4. In practice, the length of lines in the tree vary by a factor of more than two (if, e.g., you use extended futility pruning and singular extensions). So, any number between the min and the max can be considered the "depth" of the current search. I hope this helps to clarify my point. Sven.
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