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Subject: Re: incremental move generation?

Author: Georg v. Zimmermann

Date: 06:33:13 01/11/02

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Hi !

I have a move generator that is not really incremental, but more incremental
than most peoples move generator.

I do not generate all normal moves (that is non captures, promotions) at once
and later sort them by a history table. Rather I generate some moves to squares
where the same piece moving to that square used to be good in the past first.
Then when none of those produce a cutoff I generate the other normal moves.

This works ok here but would make more sense if my MoveGen wasn't very fast in
the first place.

Georg


On January 11, 2002 at 00:08:42, Wylie Garvin wrote:

>Hi,
>
>  Does anyone believe they have a "good" incremental move generator??  Can
>someone explain for me how you can get a good move ordering without generating
>all moves up front?  There seems to be a tension there.  When some people say
>"incremental", they mean "captures before non-captures".  But maybe some people
>really mean *incremental*!  How can that be done without lousy move ordering?
>
>  For curiosity's sake, here is the ordering I have in mind right now:
>    (1) Hash move, last killer for this depth (if legal)
>    (2) Generate all captures and promotions.  Attach MVV/LVA scores to
>        the moves.  Try them one by one (selection sort).
>    (3) Generate non-captures.  Attach history scores to the moves.
>        Try them one by one (selection sort).
>
>  Also, I have heard a lot of flimsy descriptions of SEE's, but I have not
>managed to distill from these any sort of idea about how to implement one
>efficiently!  Can anyone suggest how this might be implemented efficiently?
>Ultimately I want high NPS, so it may be too expensive.
>
>Thanks,
>Wylie



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