Author: Robert Hyatt
Date: 20:55:01 10/03/01
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On October 03, 2001 at 16:51:49, Torstein Hall wrote: >On October 03, 2001 at 16:10:43, Robert Hyatt wrote: > >>On October 03, 2001 at 16:02:26, Torstein Hall wrote: >> >>>What if you run two paralelle search/chess processes. One going very fast with >>>very little evaluation. The other going slow, with a big evaluation. The fast >>>one always start searching on the move calculated by the slow process with the >>>big evaluation, just checking for big materiall loss, tactical stupidities >>>further down the tree. If it find one, the fast process sends a message goes >>>back to the slow process and tells it do start work on the next best move. >>> >>>Then you perhaps can have the best from two "worlds". Intelligent search, with >>>no tactical blunders! >>> >>>Torstein >> >> >>Read Jonathan Schaeffer's reports on "Sun Phoenix". He did exactly that. >>But he did it because he was not getting a very good distributed speedup >>on larger numbers of processors. So some did a normal chess search together >>as a group, the rest ran a tactical searcher called "minix". Minix was used >>to refute moves chosen by the positional program. >> >>The problem is trying to rationalize the knowledgeable search vs the tactical >>search. If the tactical search says your positional move loses material, what >>do you do? Propose another move? And if _that_ loses material? The search >>becomes hugely inefficient... > >If the tactical search says you lose material, of course you have to change the >next best move, and so on. But that limit can perhaps be even more than a pawn? >And of course if all the first moves in your oredering are very bad, it do not >matter that much if you are not very effective. You are probably already >loosing! Maybe not. What if you are two pawns up. And the tactical search discovers that at deeper depths, the proposed best move loses one pawn. And you keep trying other moves and they keep getting rejected. And you finally discover that you are going to end up one pawn ahead rather than two. But now you have burned 10X the search time you should have used, and you can't go deeper, and you overlook the fact that you are playing a move that really loses far more than one pawn. That is the killer... > >Anyway, its another approach, and I find the consept intriguing. >Can I find Jonathan Schaffer's report on Sun Phoenix on the net somewhere? > >Torstein
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