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Subject: Re: real job of the qSearch? find quiet vs stop horizon effect

Author: Mridul Muralidharan

Date: 07:55:20 08/28/03

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Hi,

I use qsearch as a method of reaching quiet and calm positions, not as a method
to eliminate all captures.
Hence , I also try stuff like forking moves , threatening and checking moves ,
etc - these may not be captures or promotions - but normal moves that can be
very threatening and dangerous.

Of late I have been noticing that , standpat though it give a nice speedup , can
be very bad for my search - atleast the quality of output it produces.
Even though I dont allow standpat in case like when in check , etc I still see
the pv ending in positions where , due to standpat , I get the score of a lousy
position. Maybe need to tune up eval more ?!!

The observations you made w.r.t passed pawn was also observed by me - maybe like
you said , I need to identify more patterns for passed pawn eval. But the fact
remains , you cannot find all of them. So maybe it makes sense to keep these in
qsearch ?

Extensions have always only blown up the search tree for me - skewed up search
tree , where a whole bunch of useless checking moves or captures keep getting
extended , while worthwhile lines miss out due to that one extra ply search that
they need to prove they are the best moves. So I rarely extend now , even
checking moves are rarely extended , unless they are "good". Recaptures - almost
never (depending on which version :) ) , have not tried singular extensions -
because I have not understood the implementation related concepts that well ,
nor have I found much of a documentation of how it could be implemented.
I tried a search through ccc archives - way too many threads - but none of them
had something that would not have adverse effects on search - tried a few ideas
and miserably failed.
Rest of the extensions - i threw them out of the window.

My $.02

Regards
Mridul



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