Simplify pruning

STC: http://tests.stockfishchess.org/tests/view/5842be140ebc5903140c5619
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 16014 W: 2839 L: 2710 D: 10465

LTC: http://tests.stockfishchess.org/tests/view/584316a50ebc5903140c5638
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 182360 W: 22830 L: 22914 D: 136616

Retested at LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 45502 W: 5821 L: 5732 D: 33949

Bench: 4684146

diff --git a/src/search.cpp b/src/search.cpp
index 57f636535ba89ac192a87196494f748457da3993..1ffe1e97adb7291f532c1dce631adaad22f6a86c 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -936,11 +936,7 @@ moves_loop: // When in check search starts from here
           }
           else if (depth < 7 * ONE_PLY && !extension)
           {
           }
           else if (depth < 7 * ONE_PLY && !extension)
           {

-              Value v = -Value(399 + 35 * depth / ONE_PLY * depth / ONE_PLY);
-
-              if (PvNode)
-                  v += beta - alpha - 1;
-
+              Value v = -Value(400 - 100 * PvNode + 35 * depth / ONE_PLY * depth / ONE_PLY);

               if (!pos.see_ge(move, v))
                   continue;
           }
               if (!pos.see_ge(move, v))
                   continue;
           }