From: Stefan Geschwentner <Stefan-Geschwentner@web.de>
Date: Fri, 11 Nov 2016 08:46:31 +0000 (+0100)
Subject: Non-quiet pruning tweak
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=a90fc4c877b39769ebdf227b3124008ec394ad3d

Non-quiet pruning tweak

Count in the difference of static evaluation
and alpha for pruning threshold.

STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 16885 W: 3061 L: 2866 D: 10958

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 33566 W: 4428 L: 4202 D: 24936

Bench: 5513149
---

diff --git a/src/search.cpp b/src/search.cpp
index 6699991a..a74e3f25 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -944,10 +944,15 @@ moves_loop: // When in check search starts from here
                   && !pos.see_ge(move, Value(-35 * lmrDepth * lmrDepth)))
                   continue;
           }
-          else if (   depth < 7 * ONE_PLY
-                   && !extension
-                   && !pos.see_ge(move, Value(-35 * depth / ONE_PLY * depth / ONE_PLY)))
+          else if (depth < 7 * ONE_PLY && !extension)
+          {
+              Value v = Value(-35 * depth / ONE_PLY * depth / ONE_PLY);
+              if (ss->staticEval != VALUE_NONE)
+                  v += ss->staticEval - alpha - 200;
+
+              if (!pos.see_ge(move, v))
                   continue;
+          }
       }
 
       // Speculative prefetch as early as possible