Author: Robert Hyatt
Date: 18:40:42 10/13/02
Go up one level in this thread
On October 13, 2002 at 19:13:34, Jeremiah Penery wrote: >On October 13, 2002 at 17:19:50, Vincent Diepeveen wrote: > >>On October 13, 2002 at 16:55:32, Jeremiah Penery wrote: >> >>first of all. in endgames when i search dual i get huge mainlines. >>sometimes 25 ply and i have a nominal search depth of like 15 then. >> >>if i add a bunch of processors i sometimes get weird long mainlines >>because it searches nonsense. >> >>this is a well known phenomena. > >If you're getting a _big line_ of nonsense at the end of your PV, then you're >probably trying to get the full PV from the hashtable or something. I have >never seen such a thing with Crafty. (Of course, the last move or two can be >nonsense, but more often that's because of very low remaining depth, causing >easy tactics to be missed.) I haven't examined Deep Blue's mainlines to see if >they contain a lot of junk or not, but I have seen at least a few times where >some nonsense appears near the ends. They probably were trying to reconstruct >the software PV from the hashtable also, and hardware couldn't return any PV of >course. > >>now they search very small search depths with a big number of processors. >> >>So they all search incredible nonsense. >> >>also we know they extended a lot for not so common reasons. >> >>that explains obviously a lot. >> >>so the only reliable mainlines is the first mainlines of a game. we just >>have 6 games as you know. > >Do you mean the mainlines of searches after they were out of book, or while they >were in book? > >>after that the hashtable is filled with nonsense of a few ply which adds >>up quickly. extensions do the rest of the job. > >Then do you want me to make the table (of depths x(y) with the corresponding >length of mainline) with just, say, the first 10 moves of each game? I can >already tell you the results are not much different than the results for the >full game. You are _totally_ wasting your breath...
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