Author: Robert Hyatt
Date: 07:36:00 09/11/01
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On September 10, 2001 at 13:37:58, Rafael Andrist wrote: >On September 07, 2001 at 13:41:57, Robert Hyatt wrote: > >>I did this in Cray Blitz _many_ years ago (coordinated squares is the term I >>hear used most often). And I was amazed that it took longer to find the right >>move. After a mountain of debugging output, I discovered what I mentioned >>previously... "hash grafting" (the art of grafting parts of the tree from >>one zone to another by using the hash table) was helping the dumber version, >>but not the smarter one. >> > >You mix some things together! Knowledge about opposition is only one of the >tools you need to to construct a system of co-ordinated squares (german: >Gegenfeldsystem). If you implement this correctly, you should find the correct >move instantly i.e at ply 1 as my chess program Wilhelm does. > >Rafael B. Andrist You find the right move instantly... But you don't _know_ it is the right move until the score jumps. It _could_ just be a draw. And in the case of Cray Blitz, using coordinated squares, it took 25-26 plies to see the big score. It saw the right move normally at around ply=18 with the +2.5 score. With the coordinated squares stuff, it got the Kb1 move instantly, but the score didn't reach +2.5 until 7-8 plies longer than the simple version. That was the point. The better the move ordering, the less "grafting" helps a shallow search find a deep solution.
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