Add KNNvKP Endgame Heuristic

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index bbb6e5c445057a84e77efa0887d7073eb6bd96dd..2e7dd6989736fa786c2a0b5ada5d681d35cb7136 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -73,10 +73,10 @@ namespace {
 
   // Futility and reductions lookup tables, initialized at startup
   int FutilityMoveCounts[2][16]; // [improving][depth]
-  int Reductions[2][2][64][64];  // [pv][improving][depth][moveNumber]
+  int Reductions[2][64][64];  // [improving][depth][moveNumber]
 
   template <bool PvNode> Depth reduction(bool i, Depth d, int mn) {
-    return Reductions[PvNode][i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] * ONE_PLY;
+    return (Reductions[i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] - PvNode) * ONE_PLY;
   }
 
   // History and stats update bonus, based on depth
@@ -162,12 +162,11 @@ void Search::init() {
           {
               double r = log(d) * log(mc) / 1.95;
 
-              Reductions[NonPV][imp][d][mc] = int(std::round(r));
-              Reductions[PV][imp][d][mc] = std::max(Reductions[NonPV][imp][d][mc] - 1, 0);
+              Reductions[imp][d][mc] = std::round(r);
 
               // Increase reduction for non-PV nodes when eval is not improving
               if (!imp && r > 1.0)
-                Reductions[NonPV][imp][d][mc]++;
+                Reductions[imp][d][mc]++;
           }
 
   for (int d = 0; d < 16; ++d)
@@ -831,7 +830,7 @@ namespace {
         int probCutCount = 0;
 
         while (  (move = mp.next_move()) != MOVE_NONE
-               && probCutCount < 3)
+               && probCutCount < 2 + 2 * cutNode)
             if (move != excludedMove && pos.legal(move))
             {
                 probCutCount++;