Decrease reduction for moves that escape a capture

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index a945c5c7f2c29d34b18ac2ccd08ac3c6b97dcc9d..30b107ee9565c2254f93065cc5f76438f6f0a3e8 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -89,23 +89,15 @@ namespace {
     std::string do_trace(const Position& pos);
   }
 
-  // Evaluation weights, initialized from UCI options
-  enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety };
-  struct Weight { int mg, eg; } Weights[5];
+  // Evaluation weights, indexed by evaluation term
+  enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
+  const struct Weight { int mg, eg; } Weights[] = {
+    {289, 344}, {233, 201}, {221, 273}, {46, 0}, {271, 0}, {307, 0}
+  };
 
   typedef Value V;
   #define S(mg, eg) make_score(mg, eg)
 
-  // Internal evaluation weights. These are applied on top of the evaluation
-  // weights read from UCI parameters. The purpose is to be able to change
-  // the evaluation weights while keeping the default values of the UCI
-  // parameters at 100, which looks prettier.
-  //
-  // Values modified by Joona Kiiski
-  const Score WeightsInternal[] = {
-    S(289, 344), S(233, 201), S(221, 273), S(46, 0), S(289, 0)
-  };
-
   // MobilityBonus[PieceType][attacked] contains bonuses for middle and end
   // game, indexed by piece type and number of attacked squares not occupied by
   // friendly pieces.
@@ -202,9 +194,9 @@ namespace {
   const int BishopCheck       = 2;
   const int KnightCheck       = 3;
 
-  // KingDanger[attackUnits] contains the actual king danger weighted
-  // scores, indexed by a calculated integer number.
-  Score KingDanger[128];
+  // KingDanger[Color][attackUnits] contains the actual king danger weighted
+  // scores, indexed by color and by a calculated integer number.
+  Score KingDanger[COLOR_NB][128];
 
 
   // apply_weight() weighs score 'v' by weight 'w' trying to prevent overflow
@@ -213,17 +205,6 @@ namespace {
   }
 
 
-  // weight_option() computes the value of an evaluation weight, by combining
-  // two UCI-configurable weights (midgame and endgame) with an internal weight.
-
-  Weight weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
-
-    Weight w = { Options[mgOpt] * mg_value(internalWeight) / 100,
-                 Options[egOpt] * eg_value(internalWeight) / 100 };
-    return w;
-  }
-
-
   // init_eval_info() initializes king bitboards for given color adding
   // pawn attacks. To be done at the beginning of the evaluation.
 
@@ -501,7 +482,7 @@ namespace {
 
         // Finally, extract the king danger score from the KingDanger[]
         // array and subtract the score from evaluation.
-        score -= KingDanger[attackUnits];
+        score -= KingDanger[Us == Search::RootColor][attackUnits];
     }
 
     if (Trace)
@@ -898,19 +879,15 @@ namespace Eval {
 
   void init() {
 
-    Weights[Mobility]       = weight_option("Mobility (Midgame)", "Mobility (Endgame)", WeightsInternal[Mobility]);
-    Weights[PawnStructure]  = weight_option("Pawn Structure (Midgame)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
-    Weights[PassedPawns]    = weight_option("Passed Pawns (Midgame)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
-    Weights[Space]          = weight_option("Space", "Space", WeightsInternal[Space]);
-    Weights[KingSafety]     = weight_option("King Safety", "King Safety", WeightsInternal[KingSafety]);
-
     const double MaxSlope = 30;
     const double Peak = 1280;
 
     for (int t = 0, i = 1; i < 100; ++i)
     {
         t = int(std::min(Peak, std::min(0.4 * i * i, t + MaxSlope)));
-        KingDanger[i] = apply_weight(make_score(t, 0), Weights[KingSafety]);
+
+        KingDanger[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
+        KingDanger[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
     }
   }