NMP Tweaks

VoyagerOne · snicolet · commit 0e295fee25a4 · 2019-08-25T11:09:08.000+02:00
Tweak again the null move pruning preconditions. STC: LLR: 2.96 (-2.94,2.94) [0.50,4.50] Total: 19675 W: 4430 L: 4169 D: 11076 http://tests.stockfishchess.org/tests/view/5d52bc0e0ebc5925cf108300 LTC: LLR: 2.95 (-2.94,2.94) [0.00,3.50] Total: 73895 W: 12496 L: 12114 D: 49285 http://tests.stockfishchess.org/tests/view/5d52dcbc0ebc5925cf108552 Closes #2268 Bench: 3690065
diff --git a/src/search.cpp b/src/search.cpp
@@ -799,7 +799,8 @@ namespace {
         && (ss-1)->currentMove != MOVE_NULL
         && (ss-1)->statScore < 22661
         &&  eval >= beta
-        &&  ss->staticEval >= beta - 33 * depth / ONE_PLY + 299
+        &&  eval >= ss->staticEval
+        &&  ss->staticEval >= beta - 33 * depth / ONE_PLY + 299 - improving * 30
         && !excludedMove
         &&  pos.non_pawn_material(us)
         && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
