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Subject: Re: What do you do in your q-search

Author: Sune Fischer

Date: 01:36:01 11/23/02

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On November 23, 2002 at 00:57:57, Anthony Cozzie wrote:

>The discussion on verified null move pruning has got me thinking about my
>qsearch.  Right now zappa does simple-stupid qsearch: captures and recaptures,
>and I'm thinking about adding some things.  If I have a better q-search it may
>be possible to move to straight R=3, which would be faster than the current
>R=2/3 (Heinz). So I am considering adding:
>
>1. Pawn Promotions. It would be very easy to add some sort of "generate white
>pawn promotions".  Usually there would be none, but this could be determined
>quickly by a bitboard and (for those of us smart enough to use bitboards . . . .
>hehehe)

If you trying to start WWIII, this is the way to do it :)
And yeah, try adding promotions, try it all you never know if it really works
for you.

>2. Check evasion.  Right now if one of the captures puts the King in check in
>qsearch, zappa just stops.

Hmm, haven't tried that. I just continue and return stand pat score if no
capture can get it out of check. Extending in qsearch is pretty delicate, tree
is going to blow easily!

>3. A Horizon zone.  For example, Search() would call horizon() which would call
>QSearch().  In the horizon zone, Zappa would also search checks and killer
>moves.

Yeah, maybe - try it! Don't be affaid to experiment :)
It might be good to have some sort of soft transition to qsearch, use a minimal
of tactical extensions etc.

>Secondly, what are people's opinions on SEE versus futility pruning in QSearch?
>I was using SEE up until recently, when I did some experiments and decided
>Qsearch was working better.  Of course, I may just have bugs in my SEE.

"Qsearch was working better"?
SEE shouldn't replace qsearch, it's not that accurate. I use it only for move
ordering.

>I'll probably try most or all of this stuff anyway, but I'm curious what other
>people's views on this are.

Yeah, let's hear some comments.
-S.

>anthony



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