Better naming in endgame code

[stockfish] / src / material.cpp

diff --git a/src/material.cpp b/src/material.cpp
index 7e2331277d59ed8b21d40063414c3cf79ef8f50f..dc2a3a3b550c6eddaf9e8e1d378e5921c77bf72b 100644 (file)
--- a/src/material.cpp
+++ b/src/material.cpp
@@ -2,6 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -30,29 +31,31 @@ namespace {
 
   // Polynomial material imbalance parameters
 
-  //                      pair  pawn knight bishop rook queen
-  const int Linear[6] = { 1756, -164, -1067, -160,  234, -137 };
-
   const int QuadraticOurs[][PIECE_TYPE_NB] = {
     //            OUR PIECES
     // pair pawn knight bishop rook queen
-    {   0                               }, // Bishop pair
-    {  39,    2                         }, // Pawn
-    {  35,  271,  -4                    }, // Knight      OUR PIECES
-    {   0,  105,   4,    0              }, // Bishop
-    { -27,   -2,  46,   100,  -141      }, // Rook
-    {-177,   25, 129,   142,  -137,   0 }  // Queen
+    {1667                               }, // Bishop pair
+    {  40,    0                         }, // Pawn
+    {  32,  255,  -3                    }, // Knight      OUR PIECES
+    {   0,  104,   4,    0              }, // Bishop
+    { -26,   -2,  47,   105,  -149      }, // Rook
+    {-185,   24, 122,   137,  -134,   0 }  // Queen
   };
 
   const int QuadraticTheirs[][PIECE_TYPE_NB] = {
     //           THEIR PIECES
     // pair pawn knight bishop rook queen
     {   0                               }, // Bishop pair
-    {  37,    0                         }, // Pawn
-    {  10,   62,   0                    }, // Knight      OUR PIECES
-    {  57,   64,  39,     0             }, // Bishop
-    {  50,   40,  23,   -22,    0       }, // Rook
-    {  98,  105, -39,   141,  274,    0 }  // Queen
+    {  36,    0                         }, // Pawn
+    {   9,   63,   0                    }, // Knight      OUR PIECES
+    {  59,   65,  42,     0             }, // Bishop
+    {  46,   39,  24,   -24,    0       }, // Rook
+    { 101,  100, -37,   141,  268,    0 }  // Queen
+  };
+
+  // PawnSet[pawn count] contains a bonus/malus indexed by number of pawns
+  const int PawnSet[] = {
+    24, -32, 107, -51, 117, -9, -126, -21, 31
   };
 
   // Endgame evaluation and scaling functions are accessed directly and not through
@@ -91,7 +94,7 @@ namespace {
 
     const Color Them = (Us == WHITE ? BLACK : WHITE);
 
-    int bonus = 0;
+    int bonus = PawnSet[pieceCount[Us][PAWN]];
 
     // Second-degree polynomial material imbalance by Tord Romstad
     for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
@@ -99,7 +102,7 @@ namespace {
         if (!pieceCount[Us][pt1])
             continue;
 
-        int v = Linear[pt1];
+        int v = 0;
 
         for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
             v +=  QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2]
@@ -152,7 +155,7 @@ Entry* probe(const Position& pos) {
 
   if ((sf = pos.this_thread()->endgames.probe<ScaleFactor>(key)) != nullptr)
   {
-      e->scalingFunction[sf->strong_side()] = sf; // Only strong color assigned
+      e->scalingFunction[sf->strongSide] = sf; // Only strong color assigned
       return e;
   }