Pawn Tuning

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index f18e03155042112dc71e89472b55120ad26c312b..a5102db8aeb5b383c4ebe26b7ecf92462833a79f 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -1,8 +1,6 @@
 /*
   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) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file)
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -32,21 +30,21 @@ namespace {
   #define S(mg, eg) make_score(mg, eg)
 
   // Pawn penalties
-  constexpr Score Backward      = S( 9, 24);
-  constexpr Score Doubled       = S(11, 56);
-  constexpr Score Isolated      = S( 5, 15);
-  constexpr Score WeakLever     = S( 0, 56);
-  constexpr Score WeakUnopposed = S(13, 27);
+  constexpr Score Backward      = S( 8, 25);
+  constexpr Score Doubled       = S(10, 55);
+  constexpr Score Isolated      = S( 3, 15);
+  constexpr Score WeakLever     = S( 3, 55);
+  constexpr Score WeakUnopposed = S(13, 25);
 
   // Bonus for blocked pawns at 5th or 6th rank
-  constexpr Score BlockedPawn[2] = { S(-10, -3), S(-3, 3) };
+  constexpr Score BlockedPawn[2] = { S(-13, -4), S(-5, 2) };
 
   constexpr Score BlockedStorm[RANK_NB] = {
     S(0, 0), S(0, 0), S(76, 78), S(-10, 15), S(-7, 10), S(-4, 6), S(-1, 2)
   };
 
   // Connected pawn bonus
-  constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 };
+  constexpr int Connected[RANK_NB] = { 0, 5, 7, 11, 24, 48, 86 };
 
   // Strength of pawn shelter for our king by [distance from edge][rank].
   // RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king.
@@ -148,8 +146,8 @@ namespace {
         // Score this pawn
         if (support | phalanx)
         {
-            int v =  Connected[r] * (4 + 2 * bool(phalanx) - 2 * bool(opposed) - bool(blocked)) / 2
-                   + 21 * popcount(support);
+            int v =  Connected[r] * (2 + bool(phalanx) - bool(opposed))
+                   + 22 * popcount(support);
 
             score += make_score(v, v * (r - 2) / 4);
         }
@@ -221,7 +219,7 @@ Score Entry::evaluate_shelter(const Position& pos, Square ksq) const {
 
   Score bonus = make_score(5, 5);
 
-  File center = Utility::clamp(file_of(ksq), FILE_B, FILE_G);
+  File center = std::clamp(file_of(ksq), FILE_B, FILE_G);
   for (File f = File(center - 1); f <= File(center + 1); ++f)
   {
       b = ourPawns & file_bb(f);