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Subject: Re: tt table progress

Author: Robert Hyatt

Date: 04:49:20 03/12/98

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On March 12, 1998 at 02:18:25, Will Singleton wrote:

>On March 11, 1998 at 21:25:44, Robert Hyatt wrote:
>
>>On March 11, 1998 at 19:00:13, Will Singleton wrote:
>>>
>>>The percentage of true transpositions appearing in the table, for which
>>>a value can be returned immediately as the true score of the position,
>>>is small.  That is, using iterative deepening, a ply 6 search can only
>>>find transpositions within its current search, and none from the
>>>previous ply 5 search.  That would hold true for scores which narrow the
>>>window.
>>
>>actually you can get a transposition in a 5 ply search...  from the
>>starting position for example:  Nf3 Nf6 Ng1 Ng8 and there's a position
>>you should have kept from the 1 ply search you did first...
>>
>>
>
>What I meant was, once you've finished with the ply 5 iteration and go
>on to the ply 6 iteration, all of the positions stored previously have 5
>as a max depth.  So, during the ply 6 iteration, you can only try the
>move from the position, not return a score, check for a cutoff or narrow
>the window.  Right?


no... consider a five ply search like this:

1.  Nf3 Nf6 Ng1 Ng8

now you search every move at depth=5 and get a score of +.1

now you search:

1.  Nh3 Nf6 Ng1 Ng8 and you get a hit with a score of +.1... no need
to search all the 5 ply moves again.

Ditto for the other transpositions here like

Nf3 Nh6 Ng1 Ng8




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