Author: Frank Schneider
Date: 10:54:56 01/15/02
Go up one level in this thread
On January 15, 2002 at 11:02:49, Ulrich Tuerke wrote: >On January 15, 2002 at 08:51:26, David Rasmussen wrote: > >>On January 15, 2002 at 08:45:21, Severi Salminen wrote: >> >>>>Many people use node count (or time) to order root nodes, apart from always >>>>ordering the pv move of last ply first, of course. This seem to work ok. But as >>>>some people have suggested (Christophe, for one), this method isn't very much to >>>>the point and might have unwanted sideeffects. >>> >>>How is it "not to the point" and what side effects he means? For me it works. >>> >>>Severi >> >>It works for me too. >> >>The phrases "not to the point" and "side effects" are mine, not Christophe's. >>But he has expressed similar things. >> >>When I said "not to the point", I meant that 'nodes used' is not a very direct >>measure of the quality of a move, it's rather an indirect one. If I somehow >>could get the score of each root move after an iteration, I would certainly use >>that for ordering, but I can't since I use PVS. >> >>I can't name any tangible side effects, I said it "might" have side effects. >> >>/David > Hi, >One of these is for instance, that you will always have heavily extended moves >early in your list. They aren't necessarily good and possibly you waste a lot >of time until you come to - perhaps better and less expensive - less extended >moves. thats right. If your timecontrol-mechanism can stop a search before finishing an iteration the opposite seems to be clever. Suppose your first move fails low and your short on time. Then you search the "difficult" moves first (moves which took a lot of time in previous searches) and your timecontrol mechanism stops the search after only searching a few moves. This reduces the chance to find a better move. And even if you finish the iteration you probably search all the expensive moves with a bad search-window. Frank > >Uli
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