Author: Ed Schröder
Date: 04:06:18 09/28/04
Go up one level in this thread
On September 28, 2004 at 01:16:30, Aivaras Juzvikas wrote:
>On September 26, 2004 at 04:30:44, Ed Schröder wrote:
>
>>On September 26, 2004 at 00:51:17, Sergei S. Markoff wrote:
>>
>>>Some ideas on hash move extensions.
>>>The idea was invented independently by Shpeer, Rybinkin ("Mirage") and me. In
>>>most cases this is a good idea to extend TT moves to improve search stability.
>>>But what scheme will be best for doing it?
>>>
>>>In ST the method is a little curious.
>>>
>>>TT_extesion_amount=INCPLY/RootDepth (in plies).
>>>while(TT_extesion_amount*RootDepth<INCPLY) TT_extesion_amount++;
>>>
>>>Anyway it improves play of ST.
>>>
>>>I need your results to compare.
>>
>>Since Rebel 12 I am using this:
>>
>> in case of (2 consecutive best_move_from_hash_table
>> && alpha < hash_table_score + margin)
>> then { extend with one ply in case this situation happens x times }
>>
>>Notes:
>>
>>. margin is currently set to 1.00
>>. x is currently set to 4, 8, 12, 16 etc.
>>. alpha in Pro Deo's philosophy could be beta in yours.
>i dont get this x thing, does the same position have to appear 4 times to get
>extended?or only 4th 8th 12th appearance of this kind of situation gets
>extended?
The latter.
The condition:
2 consecutive best_move_from_hash_table && alpha < hash_table_score + margin
has to happen 4 times before you extend. When the counter says 8, 12, 16 etc.
extend again. In case you are using fractional extensions just extend with 0.25
for each successful condition.
My best,
Ed
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