X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fevaluate.cpp;h=7d5d435a547fe16d4fcb987f0814ad12c4733da1;hb=33682bfb98c84bf964d7ade874db1fbe5cf921d3;hp=c6740b5f65ba0f45f67c177f5b0ca1da13540589;hpb=7d4d3a2c3a4c6ce96bdbcfecf373934fdccc9b07;p=stockfish

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index c6740b5f..7d5d435a 100644
--- 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);
@@ -487,9 +486,13 @@ namespace {
                      -   9 * mg_value(score) / 8
                      +  40;
 
-        // Transform the kingDanger units into a Score, and substract it from the evaluation
+        // Transform the kingDanger units into a Score, and substract it from the evaluation.
         if (kingDanger > 0)
+        {
+            int mobilityDanger = mg_value(mobility[Them] - mobility[Us]);
+            kingDanger = std::max(0, kingDanger + mobilityDanger);
             score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16);
+        }
     }
 
     // King tropism: firstly, find squares that opponent attacks in our king flank
@@ -543,9 +546,6 @@ 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