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Subject: Re: To Bob: Crafty, move ordering with SEE

Author: Robert Hyatt

Date: 07:45:37 09/07/99

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On September 07, 1999 at 02:41:02, Alessandro Damiani wrote:

>Hi Bob!
>
>Some time back you wrote here on CCC about the move ordering of Crafty. I don't
>want to download all archive files, so I ask you now.
>
>If I remember it right, you use a SEE to order captures in the search. The
>negative captures (SwapOff(.)<0) are placed after ALL the other moves?
>
>I thought, the "state of the art" is:
>
>1. transposition table move
>2. positive captures (MVV/LVA)
>3. killer 1
>4. killer 2
>5. counter move
>6. rest of captures (MVV/LVA)
>7. history moves
>8. rest of moves (static ordering)
>


I do it like this:

1. transposition move
2. positive captures sorted by SEE score (best capture first)
3. killer 1
4. killer 2
5. history moves (4)
6. rest of moves, which just happens to do remaining captures first
   since they were generated first.

I don't do 'counter-move' as I didn't find any benefit at all.




>I define "positive capture" this way:
>Val(aggressor)<Val(victim) OR NOT Attacked(opponent, move.to).
>
>You said that the SEE gives you a better move ordering when the negative
>captures are put after number 8?


If I did, I wrote poorly...  The 'rest of the captures' come after the
history moves, because they are still at the front of the move list, and
after I give up on 'history moves' I just take the move list in order.



>
>Thank you!
>
>Alessandro (new E-mail address since today: adamiani@econophone.ch)



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