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Subject: Re: Speed is the issue ... when?

Author: J. Wesley Cleveland

Date: 11:35:36 02/01/04

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On February 01, 2004 at 12:41:53, Robert Hyatt wrote:

>On February 01, 2004 at 07:20:20, Dieter Buerssner wrote:
>
>>On January 31, 2004 at 22:08:33, Robert Hyatt wrote:
>>
>>>On January 31, 2004 at 21:37:29, J. Wesley Cleveland wrote:
>>
>>>>>What do you do with KRPP vs KR positions deep in the tree where you need to
>>>>>promote?
>>>>
>>>>I take the exact value from the KRPP vs KR table and prune. You only need
>>>>the KR** vs KR tables if you promote with a capture.
>>>
>>>How can you do that?  How do you know the promoted position is a win or a draw
>>>(or even a loss) even though the previous un-promoted position was a win or
>>>draw?
>>
>>You don't need to know it inside the search tree. As Wesley said, you have
>>already cut the tree, before you are going to promote.
>>
>>Regards,
>>Dieter
>
>I don't follow.  I reach a krppkr position at the root, and I make the best
>move, until there is no winning move except a promotion which I can't see.  So
>now I do a search, and I _still_ need the tables to make sure I don't promote
>wrongly into a draw...
>
>If you have krpp vs kr, you still reach positions where you will have to search
>or else shuffle and draw.  And there you need the right tables or you can end up
>with =Q and a draw where =N may win...

*At the root*, you need all the tables, *but* speed is much less an issue since
your "search" is only one ply. Below the root, the search cuts off whenever you
have a tablebase hit, so you only need the promoted tables when capturing at or
after promotion.



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