Author: Tony Werten
Date: 03:49:34 09/02/02
Go up one level in this thread
On September 01, 2002 at 23:47:17, Robert Hyatt wrote: >On September 01, 2002 at 13:44:45, Gian-Carlo Pascutto wrote: > >>On September 01, 2002 at 13:26:44, Robert Hyatt wrote: >> >> >>>>pawn=32 in fritz seemingly. that's all you need to know to consider >>>>it works for it. >>> >>>What does that do? I have seen large positional scores out of fritz, >>>which suggests (to me) that mtd(f) could cause some problems... >> >>That means that Fritz has a low evaluation granulatiry, which keeps the >>number of MTD passes to a minimum. There's some disagreement here between >>Vincent and the rest of the world exactly how much this matters, but it >>does matter for sure. >> >>Positional scores have nothing to do with this, I don't know where you >>got that. >> >>-- >>GCP > >I have no idea what you are talking about above. The problem that mtd(f) >encounters is with an eval that fluctuates significantly iteration to iteration. >That fluctuation is _not_ an issue of pawn values. It is an issue of >positional scores. You could have pawn = 10000 if your positional scores >don't vary much. But if they vary by more than a pawn, you will have trouble >no matter what... > >reducing the score range by a factor of 3 will help _some_. But only _some_. > >But when a program can produce scores with the positional component well over >two pawns, I don't think the actual pawn value has much effect on how mtd(f) >performs... the constantly shifting eval is going to cause lots of re-searches, >from experience.,.. If the score difference is .25 of a pawn then with pawn=32 you need 8 mtd researches, with pawn=1000 you need 250. Or am I mising something ? Tony
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