Author: Christophe Theron
Date: 09:45:11 10/28/02
Go up one level in this thread
On October 28, 2002 at 05:28:39, José Carlos wrote:
>On October 28, 2002 at 05:02:13, Nagendra Singh Tomar wrote:
>
>>On October 28, 2002 at 04:52:26, Uri Blass wrote:
>>
>>>On October 28, 2002 at 04:24:24, Nagendra Singh Tomar wrote:
>>>
>>>>On October 28, 2002 at 02:45:33, Uri Blass wrote:
>>>>
>>>>>On October 28, 2002 at 02:00:06, Nagendra Singh Tomar wrote:
>>>>>
>>>>>>On October 28, 2002 at 01:48:02, Ricardo Gibert wrote:
>>>>>>
>>>>>>>On October 28, 2002 at 01:17:41, Nagendra Singh Tomar wrote:
>>>>>>>
>>>>>>>>What all reasons can you think of for a ply 'n+1' searching lesser nodes than
>>>>>>>>ply 'n' search.
>>>>>>>>
>>>>>>>>regds
>>>>>>>>tomar
>>>>>>>
>>>>>>>The most obvious is a ply n search had really bad move ordering that gets much
>>>>>>>improved for ply n+1 thanks to the hash moves saved in the hash table.
>>>>>>
>>>>>>correct.
>>>>>>
>>>>>>One more reason can ne that 'n' was just small enough to deny null-move.
>>>>>>null-move in 'n+1' ply search saved a lot of nodes.
>>>>>
>>>>>I use null move from the first ply so there is not n that is small enough to
>>>>>deny null move.
>>>>>
>>>>>The only case when I do not start by checking null move is when the remaining
>>>>>depth is 0 or in some other special cases when I suspect a zugzwang.
>>>>>
>>>>>Uri
>>>>
>>>>But the idea behind null move is to try first with a lesser depth search and see
>>>>if it fails high ..
>>>>if you start null move search from first ply .. what is the "lesser depth" you
>>>>are going to try for ply 1 and even 2
>>>>
>>>>regds
>>>>tomar
>>>
>>>depth 0 is less than 1 or 2.
>>>
>>>Uri
>>
>>Do you really believe depth 0's result so much as to trust it for a fail high.
>>
>>tomar
>
> Sure. If null move reduction (R) = 2, which means you substract 3 to nominal
>depth and search for the same side, while your nominal depth is <= 3 null move
>will go directly to QSearch (depth 0).
>
> José C.
You can't use that in the first iterations because QSearch is not guaranteed to
return a best move at all. It returns a move only if there exist a non-losing
capture.
If the first iterations, null move is not doing anything because of this.
Christophe
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