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Subject: Re: Storing mates in the hash table

Author: Michael Henderson

Date: 11:38:10 09/07/04

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On September 07, 2004 at 10:17:08, Robert Hyatt wrote:

>On September 05, 2004 at 23:16:30, Michael Henderson wrote:
>
>>On September 05, 2004 at 17:32:57, Alessandro Scotti wrote:
>>
>>>On September 05, 2004 at 03:24:56, Michael Henderson wrote:
>>>
>>>>How was 6...Bxg1 possibly stored as the best move at that node? Once you search
>>>>all the moves, to whatever depth, the best move Qh4# is stored along with score
>>>>returned.  Is this something characteristic of MTD(f)?
>>>
>>>It was stored there because it was explored deeper. The search returned Qh4# as
>>>the best move, but then it wasn't stored in the hash table because the
>>>replacement policy (deeper is better) preferred the entry that was already
>>>there.
>>
>>In MTD(f) all searches use null window? If that is true how is it possible to
>>get an exact score/move stored in hash table?
>
>
>On the last "2 cycles" the same PV will fail low and high.  Since you need to
>store both bounds, you can always keep a "best move" even when you fail low (the
>best move comes from the next-to last or last search that failed high here...)
>
>There are other ways to do the same thing, all taking advantage of the same
>basic property of the mtd(f) search...

Does this mean that the temporary PV's you extract are actually constructed from
beta moves?  That seems to work out logically...



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