Remove ThreatByHangingPawn bonus (#1356)

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 47a65c592cdfb7ef3456f27e99cca109ebb5ae0d..fa3b0a720b2face4a2ac66d6085370f3b8e77e43 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.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) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2018 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
@@ -220,7 +220,6 @@ namespace {
   const Score WeakQueen             = S( 50, 10);
   const Score CloseEnemies          = S(  7,  0);
   const Score PawnlessFlank         = S( 20, 80);
-  const Score ThreatByHangingPawn   = S( 71, 61);
   const Score ThreatBySafePawn      = S(192,175);
   const Score ThreatByRank          = S( 16,  3);
   const Score Hanging               = S( 48, 27);
@@ -310,8 +309,8 @@ namespace {
     while ((s = *pl++) != SQ_NONE)
     {
         // Find attacked squares, including x-ray attacks for bishops and rooks
-        b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN))
-          : Pt ==   ROOK ? attacks_bb<  ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
+        b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
+          : Pt ==   ROOK ? attacks_bb<  ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK))
                          : pos.attacks_from<Pt>(s);
 
         if (pos.pinned_pieces(Us) & s)
@@ -543,9 +542,6 @@ namespace {
         safeThreats = (shift<Right>(b) | shift<Left>(b)) & weak;
 
         score += ThreatBySafePawn * popcount(safeThreats);
-
-        if (weak ^ safeThreats)
-            score += ThreatByHangingPawn;
     }
 
     // Squares strongly protected by the opponent, either because they attack the
@@ -891,7 +887,7 @@ namespace {
         Trace::add(TOTAL, score);
     }
 
-    return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view
+    return pos.side_to_move() == WHITE ? v : -v; // Side to move point of view
   }
 
 } // namespace
@@ -903,7 +899,7 @@ Score Eval::Contempt = SCORE_ZERO;
 
 Value Eval::evaluate(const Position& pos)
 {
-   return Evaluation<>(pos).value();
+   return Evaluation<>(pos).value() + Eval::Tempo;
 }
 
 /// trace() is like evaluate(), but instead of returning a value, it returns
@@ -914,7 +910,7 @@ std::string Eval::trace(const Position& pos) {
 
   std::memset(scores, 0, sizeof(scores));
 
-  Value v = Evaluation<TRACE>(pos).value();
+  Value v = Evaluation<TRACE>(pos).value() + Eval::Tempo;
   v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
 
   std::stringstream ss;