Author: David Rasmussen
Date: 08:12:28 11/27/02
Go up one level in this thread
On November 27, 2002 at 10:49:00, Richard Pijl wrote: >On November 27, 2002 at 10:01:02, David Rasmussen wrote: > >>Some time ago, along the lines of these thoughts, I proposed "negative >>extensions". That is, if you can somehow classify a move as "probably not >>interesting", you can "extend" the depth by -1 or -0.75 or whatever seems >>reasonable. Exactly as you do with normal extensions. The good thing about this >>is that nothing gets pruned for good, everything will eventually get searched >>with iterative deepening, but you search what you think is interesting first. > >Isn't this just razoring? > >IIRC Beowulf is using this instead of futility pruning ... > Well, I would say that razoring is a special case of negative extensions. Razoring normally only happens near the frontier nodes. What I am talking about can be applied anywhere in the tree. And also, razoring specifically deals with the futility of getting the score up near alpha again. I am talking about all sorts of "futile" moves. I.e. a move that moves a rook off the only open file, is probably not good. That doesn't mean that we don't want to search this move to some specified depth, in time. But it means that we might put off searching it till later, by "extending" it negatively. /David
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.