Author: KarinsDad
Date: 09:22:25 01/25/99
Go up one level in this thread
On January 24, 1999 at 16:42:03, Robert Hyatt wrote:
[snip]
>
>>Is it OK to start probing the table at the first ply beyond the root?
>
>yes, because you now have a move played at the root.. and you can play that
>if the EXACT score comes up at ply=2
This confuses me (probably since I'm still new to this).
This implies that you do not clear out your hash table immediately after the
program makes a move (i.e. during your opponent's time). For example:
D E F G
\ / \ /
B C
\ /
A
If you make move B, my thought was to remove all nodes C, F, and G assuming no
transpositions there. If a transposition was found, the count of times found
would just be decremented.
If you do clear out the hash, then you should not be able to find a
transposition until ply 4 (i.e. e4 e5 is the same as e3 e6, e4 e5). The
transposition was not found until a ply 4 search (not a ply 2, that's just the
first time it was found).
So if you do clear out the hash, then transpositions could not be found until
ply 4. If you do not clear out the hash, then transpositions could be found at
ply 1. The strange thing to me here is that if you do not clear out the hash,
you may find a few transpositions at ply 1 (from 3 ply moves ago), but it would
seem that this is not worth the effort since you would be saving information in
your table that is at least 3 ply old (and mostly next to worthless).
I suddenly realized that maybe the phrase "root" meant not the original
position, but any position passed to the search algorithm. If so, disregard my
ramblings above.
KarinsDad
[snip]
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