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Subject: Re: Stuffing PV from Triangular Table into Hash Table before each iteration

Author: Michael Henderson

Date: 11:01:36 09/14/04

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On September 14, 2004 at 09:43:06, Stuart Cracraft wrote:

>On September 12, 2004 at 23:37:05, Michael Henderson wrote:
>
>>On September 12, 2004 at 23:29:12, Michael Henderson wrote:
>>
>>>On September 12, 2004 at 22:58:22, Stuart Cracraft wrote:
>>>
>>>>I did this and the results are worse.
>>>>Clearly something is wrong
>>>>
>>>>I took the triangular table, once the iteration finishes,
>>>>and grabbed pv[0][0..N] to get the pv. I then made each
>>>>of these moves on the board and used my hash store function
>>>>to store the move that's in pv[0][i] from 0 through N into
>>>>the hash table. The reason I made them was so that the hashkey
>>>>was calculated since it is stored from a global value into
>>>>the table when a store is done. After all this, the pv[] moves
>>>>made is unmade and the position is back where it was.
>>>>
>>>>Since depth, a score, and whether it is an upper/lower/exact
>>>>are required, I threw in some ideas, but nothing worked well.
>>>
>>>I also made the mental error of thinking you had to do this...but you don't!
>>>You store the depth relative to the depth of the iteration you just did.
>>>Storing the store is optional -- if you can get the score relative to the root
>>>position score after making moves.  What I do is store no score and no bound, so
>>>nothing happens.  I only store the best move from the PV and the depth.
>>>
>>>good luck,
>>>Michael
>>
>>actually the score to store would just be the root score because it was backed
>>up from leaf to root node and is the value for every position in the PV.  Stored
>>with exact bound.
>
>I tried this and it dropped my results from 249/300 on Win at Chess
>to 78/300.

did you remember to negate the score based on the side to move? i.e. Variation 1
is worth +500, but in black's case the score would be -500.  Putting in 500 for
every entry will mess it up badly!

Michael



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