Author: Uri Blass
Date: 16:03:52 08/27/02
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On August 27, 2002 at 18:18:03, Robert Hyatt wrote: >On August 27, 2002 at 16:09:35, Uri Blass wrote: > >>On August 27, 2002 at 15:51:38, Robert Hyatt wrote: >> >><snipped> >>>>The question is if they mean to the plies that they sacrificed for the singular >>>>extensions. >>> >>>I believe so. the only comment to any sort of selective forward pruning that >>>I have ever heard from then was the futility pruning comment regarding the >>>chess processor. In the games vs the micros, they said that they turned this >>>off which slowed them by a factor of 10 or so, somehow... >> >>The point is that they did not say in the paper that they sacrificed 2 plies for >>singular extensions but that they sacrificed 2 plies for selective search >>algorithms. >> >>singular extensions are not selective search. > >yes they are, as I have explained before. "selective" means "to choose >between". You can choose to forward prune, or you can choose to selectively >extend certain lines. Either can be used to produce the same search tree/ >result... By this definition all the programs do selective search because check extensions are also selective search. If they mean only to extensions they could say directly that they sacrificed 2 plies for extensions. I understood selective search as selecting part of the moves and not anlayzing the other moves. This is different than singular extensions because the other moves are also analyzed to reduced depth. > >Their idea of selective search was _always_ to extend interesting lines, while >the forward pruner's idea is to discard uninteresting lines early. > >>selective search is what computer did in the past when they were not fast >>enough. > >Not necessarily. Forward pruning _is_ one definition of selective search. >But it isn't the _only_ definition. See above. All that "selective search" >requires is that some lines be searched more deeply than others. Forward >pruning or selective extensions both do this... > > > >> >>No doubt that it does not make sense to do selective search close to the root >>but doing selective search in the last 6 plies is a possible idea to consider. >> > >Yes... IFF you mean "forward pruning" when you say "selective search". Yes this is exactly what I mean. Uri
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