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Subject: Re: Move order %

Author: Roberto Nerici

Date: 00:08:55 03/04/04

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On March 04, 2004 at 01:08:10, Uri Blass wrote:

>On March 03, 2004 at 23:51:35, Andrew Dados wrote:
>
>>On March 03, 2004 at 22:14:12, Andrew Wagner wrote:
>>
>>>On March 03, 2004 at 22:09:51, Charles Roberson wrote:
>>>
>>>>
>>>>
>>>>   I suggest the use of history and killer moves. Give killers priority over
>>>>   history. Give winning captures priority over killers.
>>>
>>>
>>>How do you define "winning captures"?
>>
>>Really simple improvement is to put 'captures of last moved piece' first, then 2
>>killer moves, then rest of captures. Don't bother with history heuristic, it
>>hardly works. Then later you can redo this to move all winning captures before
>>killers.
>>
>>-Andrew-
>
>I disagree that history tables hardly works.
>
>Tscp has history tables and no killer moves and it has clearly better order of
>moves than 50%.

Definitely if you don't have killer moves then history tables help a lot, and
similarly if you don't have history tables then killer moves help a lot.

I took Andrew's comment to mean that adding history tables once you've got
killer moves doesn't help. I think that is a bit of a generalisation (will
depend on the engine) but certainly for mine when I added history tables after
killer moves it only made a small difference. Still, it was worth keeping...

Another thing to do is to play with the number of killer moves. Most engines use
two, I think, but I found that (without history tables) adding a third one did
help a very slightly.

Roberto/.



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