Author: Albert Silver
Date: 04:40:27 02/03/02
Go up one level in this thread
>There are other "hints" about this. Remember that the chess hardware has
>absolutely no way to return a PV move of any kind. So _every_ PV you see
>produced by their program was absolutely searched by the software part of
>the machine _only_. When you see 10(6) you can now _know_ that in addition
>to whatever PV you see (and it may well not be a full PV as they could only
>get the PV from the hash table which is not 100% reliable in producing moves
>particularly near the end of a PV) there _must_ be at _least_ 6 more PV moves
>(non-captures) plus the q-search moves. The Chess processors didn't do SE,
>but it did do classic extensions like in-check and recapture, because it was
>copied directly from Belle which did the same things.
>
>In short, _every_ PV you see has at least (N) more non-capture moves on the
>end of it, plus their q-search... If you look at their output carefully,
>you begin to get the idea of their search, because it is _definitely_ a fact
>that the hardware provides no PV information of any kind, period. Look at the
>PVs you see and when you realize that they can only come from the X(Y) (the X
>part only) part of the search, things begin to make sense. Vincent sees a
>8(4) depth and 12 moves and says "aha, that is obviously a 12 ply search and
>PV" even though it should now be obvious that that 12 ply PV came from the 8
>part of the software search, not from the 4 part of the hardware search.
I'm a bit fuzzy on the accuracy of the PV we're seeing in the logs then.
Presuming that the PVs are only the software PVs, then these may still have been
subject to changes afterwards, no? After all, it's not uncommon to search to a
given depth and say that move A is best, but with greater depth (as the hardware
will provide) move B is shown to be best. I haven't examined the logs in detail
as some here have, so I'm presuming that such an inconsistency isn't there, but
if the hardware extensions aren't capable of changing the decision making, what
good are they? Or were they simply fortunate that this never happened in the
match and that is why we don't see it in the logs. I.e. a main move in the
software-based PV that was different from the move actually played due to later
corrections provided by the hardware extensions.
Albert
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