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Subject: Re: idea for slight improvement in ordering quiet moves

Author: Stuart Cracraft

Date: 21:04:45 08/19/04

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On August 19, 2004 at 16:08:01, Eric Oldre wrote:

>a few nights ago i tried a idea i had for ordering quiet (non-capture) moves.
>
>here is my original ordering scheme:
>
>1) hash move
>2) winning captures (SEE > -.2: ordered by SEE)
>3) killer moves (non-captures)
>4) rest of moves, by SEE value.
>
>what i tried adding was:
>1) hash move
>2) winning captures (SEE > -.2: ordered by SEE)
>3) killer moves (non-captures)
>4) quiet moves that attack the space left behind by opponents last move (and
>don't have a bad SEE score)
>5) rest of moves, by SEE value.
>

I spent a lot of time with move ordering. So much I am actually
not going to revisit it in my program for a long time.

I found this worked for me:

1)  abandon SEE for move ordering. use it to remove <0 captures in quiescence
     only

2) order in main search with:

  hash
  pv moves for the side on move)
  if you don't have those two then
    make a score that is the sum of
      history heurtic
      mvv/lva
      simple centrality from/to lookup (can be same as a pc/sq table Lookup)
    qsort the whole mishmash and then start from the top down.

3) order in quiescence search with same as #2, respecting #1

I tried adding SEE to the score and killers to the above mix and it worsened
my result, substantially.

Stuart

P.S. Your mileage may vary.



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