From: Marco Costalba <mcostalba@gmail.com>
Date: Tue, 20 Oct 2009 15:14:57 +0000 (+0100)
Subject: Don't prune TT move in qsearch even if SEE < 0
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;ds=sidebyside;h=a72c55283d132e64cad9101c65e59c1f9406be83;hp=a72c55283d132e64cad9101c65e59c1f9406be83;p=stockfish

Don't prune TT move in qsearch even if SEE < 0

Even if SEE is negative there is always a good possibility
that TT move is a cut move anyway. For instance a lot of
BXN exchanges that have negative SEE can very easily be
good exchanges.

A nice side effect is a bit reduced frequency of
see_sign() calls.

After 643 games at 1+0
Mod vs Orig +174 =327 -142 52.49%  337.5/643 +17 ELO

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
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