Pawns count imbalance table

[stockfish] / src / material.cpp

diff --git a/src/material.cpp b/src/material.cpp
index f73977b5f369641dfc427507ae66fcc035c58928..498ef33fe35ee0727e46325da5c769cb609a5aa6 100644 (file)
--- a/src/material.cpp
+++ b/src/material.cpp
@@ -2,7 +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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, 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
@@ -31,14 +31,11 @@ namespace {
 
   // Polynomial material imbalance parameters
 
-  //                      pair  pawn knight bishop rook queen
-  const int Linear[6] = { 1667, -168, -1027, -166,  238, -138 };
-
   const int QuadraticOurs[][PIECE_TYPE_NB] = {
     //            OUR PIECES
     // pair pawn knight bishop rook queen
-    {   0                               }, // Bishop pair
-    {  40,    2                         }, // Pawn
+    {1667                               }, // Bishop pair
+    {  40,    0                         }, // Pawn
     {  32,  255,  -3                    }, // Knight      OUR PIECES
     {   0,  104,   4,    0              }, // Bishop
     { -26,   -2,  47,   105,  -149      }, // Rook
@@ -56,6 +53,11 @@ namespace {
     { 101,  100, -37,   141,  268,    0 }  // Queen
   };
 
+  // PawnsSet[count] contains a bonus/malus indexed by number of pawns
+  const int PawnsSet[9] = { 
+     24, -32, 107, -51, 117, -9, -126, -21, 31
+  };
+
   // Endgame evaluation and scaling functions are accessed directly and not through
   // the function maps because they correspond to more than one material hash key.
   Endgame<KXK>    EvaluateKXK[] = { Endgame<KXK>(WHITE),    Endgame<KXK>(BLACK) };
@@ -92,7 +94,7 @@ namespace {
 
     const Color Them = (Us == WHITE ? BLACK : WHITE);
 
-    int bonus = 0;
+    int bonus = PawnsSet[pieceCount[Us][PAWN]];
 
     // Second-degree polynomial material imbalance by Tord Romstad
     for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
@@ -100,7 +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]