Author: Robert Hyatt
Date: 20:14:45 08/16/03
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On August 16, 2003 at 07:23:49, Gian-Carlo Pascutto wrote: >On August 15, 2003 at 22:56:34, Robert Hyatt wrote: > >>On August 14, 2003 at 15:27:06, Peter Fendrich wrote: >> >>>1FH = The ratio where the first generated move in the node is a Fail High. >>> >>>I experimented with removing the the hash table and became a bit surprised. >>>Normally I have about 1FH = 95-96%. When I removed the hash table that figure >>>raised to more like 1FH = 96-97% while the search depth, as expected, was >>>decreased. >>> >>>Increased 1FH when removing the hash table. Is this normal? >> >>Probably. You increased the size of the tree. And for the extra stuff you >>searched, you searched it pretty accurately. But you _did_ search it, which >>slowed you down. :) > >No! - That does not make any sense at all. Sorry, but it makes _lots_ of sense. If you don't try a hash table move first, then you will probably try captures and captures have re-captures that work instantly. Hence more cutoffs. Just try it... The hash move is often _not_ a capture. But if you try a capture first, then the corresponding re-capture will be an instant cutoff that is easier to find than a reply to a non-capture. > >"the extra stuff you searched, you searched it pretty accurately" > >If we disabled hashing and hence handicap move ordering, we'll do >worse, not better, on average. > >Yes, we may generate extra nodes and do well there, but that's certainly >not what we should expected in the average case, since we just made >our move ordering worse! > >Do you see your contradiction? Not at all. See above. Which is easier to refute, a non-capture or a capture? Answer: A capture. > >-- >GCP
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