Author: Tom Likens
Date: 14:09:31 05/08/04
Go up one level in this thread
On May 08, 2004 at 16:55:23, Robert Hyatt wrote:
>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?
>
>Correct...
>
>
>>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.
>
>Correct again. :)
>
>>
>>Is this correct?
>>
>>William
Whew!! If you had answered "Incorrect" to both of those questions Bob, I
would have wasted *years* of effort!! ;)
regards,
--tom
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