Author: Bas Hamstra
Date: 17:05:50 09/19/99
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Thanks again. It is so logical, after reading your reply, as usual :) Don't know what I was thinking. But wait, maybe I do. The last couple of plies, the nullmove search is no more than a QSearch. Nullsearches for the last plies have in fact the *same* depth (namely 0). When you put the normal searchdepth in the hashtable you don't profit from that fact. But I'll try it the normal way first and come back to this if necessary. (this is a great place!) Regards, Bas Hamstra. On September 19, 1999 at 13:52:12, Robert Hyatt wrote: >On September 19, 1999 at 12:11:39, Bas Hamstra wrote: > >>Hello friends, >> >>When you do nullmove everywhere, it causes a lot of qsearches. Without nullmove >>I have a good qnode/node rate, roughly around 5-10% or so. With nullmove that >>worsens quite a bit, I see rates over 100% frequently. Is that normal? >> >>I read about nullhashing, a few times. I don't hash the result of a nullmove >>search. To be more precise: when a position is cut by a nullmovesearch I don't >>put that position in the hashtable, and just return Beta. Should I? And has that >>got something to do with the bad qrates I'm seeing? > >can't answer that, but I don't see why you don't hash the result, as it is >obviously the right answer in that position... I always do a hash store >before I fail high, except when the fail high is after a hash probe, of >course.. > > > > >> >>Can someone give a few pointers for nullhashing? Just putting a position that is >>about to be cut by nullmove in the table, as a normal upperbound record, but >>without a move? With flag "NULLHASH"? Record only to be used by nullmove, so >>store with adjusted depth = depth-R ? That's how I would figure it, and I tried >>it quickly, but without much result... >> > >I store no move, a LOWER flag, and the normal depth.. > > > >>A second question: I don't store leaf-nodes at all, just see no point in that. I >>would like to check if that's normal. A simple yes is enough :) >> > >I don't. I used to. The only reason I don't is that it reduces hash table >contention and lets me get away with smaller tables when memory is not as big >as I'd like... > > > > >>Regards, >>Bas Hamstra.
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