Author: Frank Phillips
Date: 13:54:40 05/08/04
Go up one level in this thread
On May 08, 2004 at 16:38:55, William Bryant wrote:
>On May 08, 2004 at 13:18:36, Robert Hyatt wrote:
>
>>On May 08, 2004 at 12:56:24, Jeff GAZET wrote:
>>
>>>>>>Hi,
>>>>>>when getting hashtable informations like this :
>>>>>>switch(target->flags)
>>>>>> {
>>>>>> case hashfEXACT: return target->eval; break;
>>>>>> case hashfALPHA: if(target->eval<=alpha) {return alpha;} break;
>>>>>> case hashfBETA: if(target->eval>=beta) {return beta;} break;
>>>>>> }
>>>>>>In which case mustn'nt we do a null-move ?
>>>>>>Thanks.
>>>
>>>>>If your hash record for a node (position) does not have enough draft to return
>>>>>from the search at this point, but does have enough draft
>>>>> (ie current_depth – R) for the null move search and predicts that it will
>>>>> not fail high (ie the stored hashflag is not a lower bound and the stored
>>>>>> value is < beta) then you can avoid the null move search for this node.
>>>
>>>I don't understand what means "draft". I would understand better a piece of code
>>>than a sentence, if possible.
>>>So you say :
>>>if(depth-R>0 && target->eval<beta)... DoNull=FALSE... ? :-)
>>>Thanks
>>
>> if (type == UPPER && depth-R <= draft && tableval < beta)
>> avoid_null = 1;
>>
>>Draft is "remaining depth" and is the depth value stored in the hash table...
>
>Just to clarify an important, because I think I am confused.
>The draft value is how much deeper the search is planning to search (before
>quescence)
>remaining depth, ___NOT___ the depth of the search up to this point?
>So a value stored in the hash table near the root, has a greater Draft, and a
>greater value,
>than a value stored near the leaves.
>
>Is this correct?
>
>William
Yes.
depth=4 has a deeper draft than depth=3 etc.
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