Author: Robert Hyatt
Date: 14:09:30 06/12/01
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On June 12, 2001 at 16:47:39, David Rasmussen wrote: >On June 12, 2001 at 16:15:08, Robert Hyatt wrote: > >>>I'm not saying I know how a system such as the one I describe, can be done. But >>>I will think a bit more about it, since I don't like the idea of missing book >>>positions in cases where it would be a good idea not to. >> >>It is trivial to do. Just use the complete 64 bit hash signature, rather than >>the 16+48 approach I use. I used this in Cray Blitz, and in early versions >>of Crafty. The current approach has a couple of good points (speed, not >>transposing from one line to another unless _both_ are in the book already). >>The other approach is much slower (you must search for the hash signature since >>there is no way to 'group' them as I do now) but will find _any_ possible >>transposition. That got us into trouble many times with Cray Blitz. We >>followed a book line to a point where we wanted to play move "X" or else go >>off on our own, depending on what the opponent did. And he would play something >>that would jump us to another book line that ended up much worse than we wanted. > >I was talking about a system that allows "general" transistions as we're talking >about, but which _also_ will take the offered bishop in the example you've >given. I don't see the simple approach (that I of course was aware of), doing >that. > >And the general problems you describe with the approach, when there isn't >anything tactical going on, aren't they essentially "just" shorcomings of the >book in question? I mean, a good book would not allow this, would it? I'm not sure what you mean. IE transpositions are possible all over the place, piecing two games together that were never really played, only because they share a common (or potentially common) position somewhere in the pathway. I don't see how to do some but not all. IE either you do all possible transpositions, which is what I did in Cray Blitz and in early crafty versions, or you miss the special case of a place where you don't have a known book position, but if you play a particular move you will...
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