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

Author: Robert Hyatt

Date: 17:16:49 02/01/04

Go up one level in this thread


On February 01, 2004 at 14:35:36, J. Wesley Cleveland wrote:

>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.

And we close the circle.  That was _exactly_ what I said.  I need 'em to do the
right promotion.  But they are too slow on anything but a fast disk.




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