Author: Robert Hyatt
Date: 18:28:32 11/25/02
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On November 25, 2002 at 16:31:01, David Rasmussen wrote: >On November 25, 2002 at 15:16:35, Andreas Guettinger wrote: > >>On November 25, 2002 at 14:17:38, Robert Hyatt wrote: >> >>> >>>Crafty's is not bad. This is a classic trade-off issue. It could easily be >>>made more >>>accurate. IE not using absolute-pinned pieces and so forth. But the question >>>becomes, >>>does the cost of the extra accuracy result in tree sizes that are small enough >>>that the >>>savings offsets the added computational cost... >>> >>>It's easy to make it more accurate. But the question is, "is it worth it?" >> > >We're not just talking tree sizes here, are we? See below. > >> >>I would say no. The differences between MVV/LVA are already not that big, so >>even if the SEE is not the most accuratest, if it is only used for move >>ordering, that doesn't really. More important is that it is fast and only >>executed when necessary. >> > >For move ordering, Crafty's is probably fine. That is, I don't think that there >is a lot to gain in move ordering and therefore tree size, by a more accurate >SEE. But SEE is also, in Crafty at least, and in Chezzz (which uses a >SEE-function similar to Crafty's), used to throw out apparently futile captures. >If the SEE isn't good enough, this will lead to tactical problems, by throwing >out what seems to be a futile capture, but isn't. I asked my original question >with that aspect in mind. How safe is it to throw a capture out, using Crafty's >SEE? > >/David The concept of a "captures only" q-search is so flawed that tossing out a few extra captures, or keeping a few unnecessary captures is basically unimportant... There are so many positions where a capture is not the best move that to hope for much from the q-search is mostly wishful thinking...
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