Increase reduction based on the number of best move changes.

lonfom169 · vondele · commit b5781150ea85 · 2020-11-10T18:21:05.000+01:00
Thanks to Vizvezdenec for the PvNode idea and also to vondele the !PvNode idea. Passed STC: LLR: 2.94 (-2.94,2.94) {-0.25,1.25} Total: 19120 W: 1998 L: 1839 D: 15283 Ptnml(0-2): 76, 1445, 6375, 1572, 92 https://tests.stockfishchess.org/tests/view/5fa8af3e67cbf42301d6a6c9 Passed LTC: LLR: 2.94 (-2.94,2.94) {0.25,1.25} Total: 75584 W: 3454 L: 3205 D: 68925 Ptnml(0-2): 54, 2832, 31771, 3081, 54 closes #3224 Bench: 3595418
diff --git a/AUTHORS b/AUTHORS
@@ -19,6 +19,7 @@ Alain Savard (Rocky640)
 Alayan Feh (Alayan-stk-2)
 Alexander Kure
 Alexander Pagel (Lolligerhans)
+Alfredo Menezes (lonfom169)
 Ali AlZhrani (Cooffe)
 Andrew Grant (AndyGrant)
 Andrey Neporada (nepal)
diff --git a/src/search.cpp b/src/search.cpp
@@ -1169,6 +1169,9 @@ namespace {
           if (ss->ttPv)
               r -= 2;
 
+          if (!PvNode && depth > 10 && thisThread->bestMoveChanges <= 2)
+              r++;
+
           if (moveCountPruning && !formerPv)
               r++;
 
