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Subject: Re: History Heuristic

Author: Robert Hyatt

Date: 09:33:30 03/16/04

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On March 16, 2004 at 11:19:17, Renze Steenhuisen wrote:

>On March 16, 2004 at 11:15:43, Renze Steenhuisen wrote:
>
>>On March 16, 2004 at 11:04:39, Vincent Diepeveen wrote:
>>
>>>On March 16, 2004 at 04:41:40, Renze Steenhuisen wrote:
>>>
>>>It seems to differ from program to program.
>>>
>>>In diep it doesn't work at all.
>>>
>>>I tried many different forms of keeping track of the HH table. There is no need
>>>for just [64][64] there is many different forms possible. Like for each side
>>>makes already more sense.
>>>
>>>In diep the general killermove also hardly works. HH is probably even more a
>>>'general overal killer'. In diep basically local killers who continuesly get
>>>replaced work very well.
>>>
>>>All big slow global stuff just doesn't work for DIEP.
>>>
>>>I had the same result for my draughts program Napoleon.
>>
>>Yeah, I read your previous post on this topic from the archive but thanks
>>anyway! I have tried some different things, but I am a bit puzzled.
>>
>>I got very good numbers for gain in move-ordering for shallow searches (say 5-7
>>ply), so I tried 2 things:
>
>ARGH! I hate it that TAB doesn't work!
>
>   1> apply HH to the subtrees with that shallow (5-7 ply) remaining depth, and
>      reset them for every other subtree, ofcourse
>   2> apply HH to the top (5-7 ply) only
>
>It did not have the effect I thought it would have...
>
>Any ideas on the topic? Which should be doing better anyway? Or apply them both!
>
>Renze

Neither.  At the root, before starting a brand new search (not a new iteration)
age the counters...  IE in Crafty, in "main()" I shift the counters right 8 bits
(divide them by 256).  This ages old history counters away over a few moves,
without losing important values instantly...





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