Author: Tom Likens
Date: 16:36:10 02/27/06
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On February 27, 2006 at 13:41:57, Robert Hyatt wrote: >On February 27, 2006 at 12:46:40, Frank Phillips wrote: > >>So you do this at only (expected) cut nodes? >>Tord seems to imply at anything other than pvNodes. >> >>Frank > > >I do it at _all_ nodes. I think Tord does as well. The problem is it is >impossible to predict with high accuracy whether a node is CUT or ALL (btw, this >is only useful at ALL nodes, since we have to search all moves and reducing the >depth reduces the effort required to accomplish that). Bob/Tord, I just got to my hotel (I'm on a business trip for the next few days) and I see CCT8 has sparked a number of interesting threads. Reductions are especially fertile ground. I'd be careful reducing at PV nodes. I saw a significant drop in djinn's positional strength when I applied this at PV nodes. At the very least you might want to skip it at nodes where alpha/beta == RootAlpha/RootBeta. Ideally, as you mentioned you only want to apply this at ALL nodes. I've also experimented with "flipping" CUT nodes to ALL nodes if we search more than 'x' moves at a CUT node without a fail-high or an improvement in the score. Once the flip occurs all the nodes below are toggled in the normal CUT -> ALL -> CUT etc., and these nodes become eligible for reduction. Also do you allow multiple recursive reductions or do you limit them? I've applied the adaptive reduction idea a while back, with mixed results. It's likely I didn't test this enough because I was in the middle of a major project at work and could only give it a small percentage of my attention :-( regards, --tom
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