Adjust pruning constants

Vizvezdenec · vondele · commit 44b1ba89a95f · 2022-01-10T19:35:53.000+01:00
This patch is a modification of original tuning done by vondele that failed yellow. Value differences are divided by 2. Passed STC https://tests.stockfishchess.org/tests/view/61d918239fea7913d9c64cdf LLR: 2.94 (-2.94,2.94) <0.00,2.50> Total: 98968 W: 26248 L: 25858 D: 46862 Ptnml(0-2): 392, 11085, 26156, 11443, 408 Passed LTC https://tests.stockfishchess.org/tests/view/61d99e3c9fea7913d9c663e4 LLR: 2.95 (-2.94,2.94) <0.50,3.00> Total: 215232 W: 58191 L: 57492 D: 99549 Ptnml(0-2): 271, 22124, 62138, 22801, 282 closes #3885 bench 4572746
diff --git a/src/search.cpp b/src/search.cpp
@@ -1040,7 +1040,7 @@ namespace {
                   continue;
 
               // SEE based pruning (~9 Elo)
-              if (!pos.see_ge(move, Value(-218) * depth))
+              if (!pos.see_ge(move, Value(-217) * depth))
                   continue;
           }
           else
@@ -1051,15 +1051,15 @@ namespace {
 
               // Continuation history based pruning (~2 Elo)
               if (   lmrDepth < 5
-                  && history < -3000 * depth + 3000)
+                  && history < -3875 * (depth - 1))
                   continue;
 
               history += thisThread->mainHistory[us][from_to(move)];
 
               // Futility pruning: parent node (~9 Elo)
               if (   !ss->inCheck
                   && lmrDepth < 8
-                  && ss->staticEval + 142 + 139 * lmrDepth + history / 64 <= alpha)
+                  && ss->staticEval + 138 + 137 * lmrDepth + history / 64 <= alpha)
                   continue;
 
               // Prune moves with negative SEE (~3 Elo)
