Fix check for bishop pair in material imbalance
authorEelco de Groot <eelcogro@gmail.com>
Mon, 2 Sep 2013 20:50:32 +0000 (22:50 +0200)
committerMarco Costalba <mcostalba@gmail.com>
Tue, 3 Sep 2013 17:40:34 +0000 (19:40 +0200)
commit679c2ea2275d6a978cea10e4260ee0598e044c82
treea4bf81ac48b194ac2af861f072417c5c7335bca9
parent9ff594c3a9e3517eb12f0abfced6baa2ac58e4c1
Fix check for bishop pair in material imbalance

Prefer pos.bishop_pair() to pos.count<BISHOP>(WHITE) > 1
because the first checks that the two bishops are on
different color squares.

Although the change seems to kick in only in very rare cases,
quite surprisingly it was able to pass SPRT test at short TC.

LLR: 2.95 (-2.94,2.94)
Total: 39818 W: 8174 L: 7956 D: 23688

bench: 3453941
src/material.cpp