Introduce scale factor in pawn evaluation

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 86e5999f85cfe49fd899ee38ae34a2a5fd4309cb..5f86227c2c5e9718e4ec76a967638167054ebff0 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2009 Marco Costalba
+  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, 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
@@ -224,15 +224,19 @@ namespace {
 
   const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
 
-  // Bonuses for safe checks, initialized from UCI options
-  int QueenContactCheckBonus, DiscoveredCheckBonus;
-  int QueenCheckBonus, RookCheckBonus, BishopCheckBonus, KnightCheckBonus;
+  // Bonuses for safe checks
+  const int QueenContactCheckBonus = 3;
+  const int DiscoveredCheckBonus   = 3;
+  const int QueenCheckBonus        = 2; 
+  const int RookCheckBonus         = 1;
+  const int BishopCheckBonus       = 1; 
+  const int KnightCheckBonus       = 1;
 
   // Scan for queen contact mates?
   const bool QueenContactMates = true;
 
-  // Bonus for having a mate threat, initialized from UCI options
-  int MateThreatBonus;
+  // Bonus for having a mate threat
+  const int MateThreatBonus = 3;
 
   // InitKingDanger[] contains bonuses based on the position of the defending
   // king.
@@ -426,6 +430,13 @@ Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) {
           factor[BLACK] = sf;
   }
 
+  // If we don't already have an unusual scale factor, use pawn
+  // evaluation ones.
+  if (factor[WHITE] == SCALE_FACTOR_NORMAL)
+      factor[WHITE] = ei.pi->scale_factor(WHITE);
+  if (factor[BLACK] == SCALE_FACTOR_NORMAL)
+      factor[BLACK] = ei.pi->scale_factor(BLACK);
+
   // Interpolate between the middle game and the endgame score
   Color stm = pos.side_to_move();
 
@@ -866,7 +877,7 @@ namespace {
   }
 
 
-  // evaluate_passed_pawns() evaluates the passed pawns of the given color
+  // evaluate_passed_pawns_of_color() evaluates the passed pawns of the given color
 
   template<Color Us>
   void evaluate_passed_pawns_of_color(const Position& pos, int movesToGo[], Square pawnToGo[], EvalInfo& ei) {
@@ -957,7 +968,7 @@ namespace {
             qsq = relative_square(Us, make_square(square_file(s), RANK_8));
             d =  square_distance(s, qsq)
                - square_distance(theirKingSq, qsq)
-               + (Us != pos.side_to_move());
+               + int(Us != pos.side_to_move());
 
             if (d < 0)
             {
@@ -1200,36 +1211,23 @@ namespace {
 
   void init_safety() {
 
-    QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus");
-    QueenCheckBonus        = get_option_value_int("Queen Check Bonus");
-    RookCheckBonus         = get_option_value_int("Rook Check Bonus");
-    BishopCheckBonus       = get_option_value_int("Bishop Check Bonus");
-    KnightCheckBonus       = get_option_value_int("Knight Check Bonus");
-    DiscoveredCheckBonus   = get_option_value_int("Discovered Check Bonus");
-    MateThreatBonus        = get_option_value_int("Mate Threat Bonus");
-
-    int maxSlope = get_option_value_int("King Safety Max Slope");
-    int peak     = get_option_value_int("King Safety Max Value") * 256 / 100;
-    double a     = get_option_value_int("King Safety Coefficient") / 100.0;
-    double b     = get_option_value_int("King Safety X Intercept");
-    bool quad    = (get_option_value_string("King Safety Curve") == "Quadratic");
-    bool linear  = (get_option_value_string("King Safety Curve") == "Linear");
+    int maxSlope = 30;
+    int peak     = 0x500;
+    double a     = 0.4;
+    double b     = 0.0;
 
     for (int i = 0; i < 100; i++)
     {
         if (i < b)
             SafetyTable[i] = Value(0);
-        else if (quad)
+        else
             SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
-        else if (linear)
-            SafetyTable[i] = Value((int)(100 * a * (i - b)));
     }
 
-    for (int i = 0; i < 100; i++)
+    for (int i = 1; i < 100; i++)
     {
-        if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
-            for (int j = i + 1; j < 100; j++)
-                SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
+        if (SafetyTable[i] - SafetyTable[i - 1] > maxSlope)
+            SafetyTable[i] = SafetyTable[i - 1] + Value(maxSlope);
 
         if (SafetyTable[i]  > Value(peak))
             SafetyTable[i] = Value(peak);