Zero more redundant coefficients

[stockfish] / src / material.cpp

diff --git a/src/material.cpp b/src/material.cpp
index 995a5b541e185e6a0e772e02fb879ba6c832e09a..4fd125de25bc5e1740f774e2eff0e07a7871a05f 100644 (file)
--- a/src/material.cpp
+++ b/src/material.cpp
@@ -39,14 +39,14 @@ namespace {
   const Value RedundantRook  = Value(554);
 
   //                                  pair  pawn knight bishop rook queen
-  const int LinearCoefficients[6] = { 1617, -162, -1172, -190,  105,  26 };
+  const int LinearCoefficients[6] = { 1852, -162, -1122, -183,  105,  26 };
 
   const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = {
     // pair pawn knight bishop rook queen
-    {   7                               }, // Bishop pair
+    {   0                               }, // Bishop pair
     {  39,    2                         }, // Pawn
     {  35,  271,  -4                    }, // Knight
-    {   7,  105,   4,    7              }, // Bishop
+    {   0,  105,   4,    0              }, // Bishop
     { -27,   -2,  46,   100,   56       }, // Rook
     {  58,   29,  83,   148,   -3,  -25 }  // Queen
   };
@@ -54,12 +54,12 @@ namespace {
   const int QuadraticCoefficientsOppositeColor[][PIECE_TYPE_NB] = {
     //           THEIR PIECES
     // pair pawn knight bishop rook queen
-    {  41                               }, // Bishop pair
-    {  37,   41                         }, // Pawn
-    {  10,   62,  41                    }, // Knight      OUR PIECES
-    {  57,   64,  39,    41             }, // Bishop
-    {  50,   40,  23,   -22,   41       }, // Rook
-    { 106,  101,   3,   151,  171,   41 }  // Queen
+    {   0                               }, // Bishop pair
+    {  37,    0                         }, // Pawn
+    {  10,   62,   0                    }, // Knight      OUR PIECES
+    {  57,   64,  39,     0             }, // Bishop
+    {  50,   40,  23,   -22,    0       }, // Rook
+    { 106,  101,   3,   151,  171,    0 }  // Queen
   };
 
   // Endgame evaluation and scaling functions accessed direcly and not through
@@ -113,7 +113,7 @@ namespace {
                 + RedundantQueen * pieceCount[Us][QUEEN];
 
     // Second-degree polynomial material imbalance by Tord Romstad
-    for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++)
+    for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
     {
         pc = pieceCount[Us][pt1];
         if (!pc)
@@ -121,7 +121,7 @@ namespace {
 
         v = LinearCoefficients[pt1];
 
-        for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++)
+        for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
             v +=  QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2]
                 + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2];
 
@@ -173,18 +173,10 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
       return e;
   }
 
-  // Draw by insufficient material (trivial draws like KK, KBK and KNK)
-  if (   !pos.pieces(PAWN)
-      &&  pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) <= BishopValueMg)
-  {
-      e->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()];
-      return e;
-  }
-
-  // Minor piece endgame with at least one minor piece per side and
-  // no pawns. Note that the case KmmK is already handled by KXK.
   if (!pos.pieces(PAWN) && !pos.pieces(ROOK) && !pos.pieces(QUEEN))
   {
+      // Minor piece endgame with at least one minor piece per side and
+      // no pawns. Note that the case KmmK is already handled by KXK.
       assert((pos.pieces(WHITE, KNIGHT) | pos.pieces(WHITE, BISHOP)));
       assert((pos.pieces(BLACK, KNIGHT) | pos.pieces(BLACK, BISHOP)));
 
@@ -248,7 +240,8 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
       }
   }
 
-  // No pawns makes it difficult to win, even with a material advantage
+  // No pawns makes it difficult to win, even with a material advantage. This
+  // catches some trivial draws like KK, KBK and KNK
   if (!pos.count<PAWN>(WHITE) && npm_w - npm_b <= BishopValueMg)
   {
       e->factor[WHITE] = (uint8_t)