Don't overwrite exsisting TT with null search value
authorMarco Costalba <mcostalba@gmail.com>
Wed, 14 Apr 2010 05:13:24 +0000 (06:13 +0100)
committerMarco Costalba <mcostalba@gmail.com>
Fri, 16 Apr 2010 04:52:18 +0000 (05:52 +0100)
commitec0a650dff9ad78eff89e0c7fb04491f79fa7945
tree79ecc185ba5a6c6f6fce459b1d298181d42dbf77
parentabae3c5678897be39fd7a082543937f846dcfbd5
Don't overwrite exsisting TT with null search value

Real search is considered of higher quality then null
search one.

This allows to fix the zugzwang issue with a minimal
impact on ELO.

Zugzwang verified on position:

8/7P/8/8/K2b4/p7/1k6/1B6 b - -

After 999 games at 1+0 on my QUAD
Mod vs Orig(94bb196) +168 =657 -174  -2 ELO

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
src/search.cpp