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Subject: Re: How important is a root search function ?

Author: Mridul Muralidharan

Date: 02:20:00 09/03/03

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Hi,

  You might have forgotten to add another thing :
Usually , no null move at root.

Regards
Mridul

On September 02, 2003 at 03:44:44, Richard Pijl wrote:

>On September 01, 2003 at 18:53:48, Geoff wrote:
>
>>Hi
>>
>>I have been improving my chess program so far by concentrating on speeding up
>>the search. I have got this reasonably fast now in terms of nodes per second,
>>but the program is still searching far too many nodes to get down to a
>>particular depth.
>>
>>I noticed that quite a few other programs have a separate search root function,
>>with a specific root move ordering function, I haven't bothered doing this so
>>far as I couldn't really see how it would give that good an improvement ?  Is it
>>really worth doing?
>>
>>For info, my program currently uses fairly standard PVS search routine, alpha
>>beta with aspiration window, history array ordering, null move R=2, TT table.
>>
>>Any other techniques I should be looking at next to get the nodes search down
>>another notch ? Thanks
>>
>>                    Geoff
>
>There are a number of things special for the rootnode:
>- There is only one, so extra work done here is almost for free
>- It has large subtrees, so only slightly improved ordering can give big
>improvements
>- Moves are generated only once, so it is easy to keep statistics on the moves
>to help you improve ordering, e.g. number of nodes in the subtrees, scores
>returned by the search (especially when you use fail soft) etc.
>
>Richard



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