From: Alain SAVARD <support@multicim.com>
Date: Fri, 5 Aug 2016 14:09:22 +0000 (-0400)
Subject: Simplify space formula
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=8abb98455f6fa78092f650b8bae9c166f1b5a315

Simplify space formula

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 16868 W: 3260 L: 3132 D: 10476

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 16910 W: 2381 L: 2255 D: 12274

bench: 6663531
---

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 489422fc..84a37dfc 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -703,10 +703,9 @@ namespace {
 
     // ...count safe + (behind & safe) with a single popcount
     int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
-    int weight =  pos.count<KNIGHT>(Us) + pos.count<BISHOP>(Us)
-                + pos.count<KNIGHT>(Them) + pos.count<BISHOP>(Them);
+    int weight = pos.count<ALL_PIECES>(Us);
 
-    return make_score(bonus * weight * weight * 2 / 11, 0);
+    return make_score(bonus * weight * weight  / 22, 0);
   }