X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fpawns.cpp;h=d365ba121c3e66a9e5bc2852113ecab62b36d4bd;hb=268c00b648ba4a48be79a849dde5733e6705ddbf;hp=467137b3133ef84a4d7fef1a0f64d8de50bf761e;hpb=a5e3b4eddede900c1df610e8e25026a79d706500;p=stockfish

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 467137b3..d365ba12 100644
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -38,7 +38,9 @@ namespace {
   constexpr Score WeakLever     = S( 0, 56);
   constexpr Score WeakUnopposed = S(13, 27);
 
-  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)};
+  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 };
@@ -66,6 +68,12 @@ namespace {
   #undef S
   #undef V
 
+
+  /// evaluate() calculates a score for the static pawn structure of the given position.
+  /// We cannot use the location of pieces or king in this function, as the evaluation
+  /// of the pawn structure will be stored in a small cache for speed reasons, and will
+  /// be re-used even when the pieces have moved.
+
   template<Color Us>
   Score evaluate(const Position& pos, Pawns::Entry* e) {
 
@@ -145,22 +153,22 @@ namespace {
 
         else if (!neighbours)
         {
-            score -=   Isolated
-                     + WeakUnopposed * !opposed;
-
-            if (   (ourPawns & forward_file_bb(Them, s))
-                && popcount(opposed) == 1
+            if (     opposed
+                &&  (ourPawns & forward_file_bb(Them, s))
                 && !(theirPawns & adjacent_files_bb(s)))
                 score -= Doubled;
+            else
+                score -=  Isolated
+                        + WeakUnopposed * !opposed;
         }
 
         else if (backward)
-            score -=   Backward
-                     + WeakUnopposed * !opposed;
+            score -=  Backward
+                    + WeakUnopposed * !opposed;
 
         if (!support)
-            score -=   Doubled * doubled
-                     + WeakLever * more_than_one(lever);
+            score -=  Doubled * doubled
+                    + WeakLever * more_than_one(lever);
     }
 
     return score;
@@ -170,6 +178,7 @@ namespace {
 
 namespace Pawns {
 
+
 /// Pawns::probe() looks up the current position's pawns configuration in
 /// the pawns hash table. It returns a pointer to the Entry if the position
 /// is found. Otherwise a new Entry is computed and stored there, so we don't
@@ -196,7 +205,7 @@ Entry* probe(const Position& pos) {
 /// penalty for a king, looking at the king file and the two closest files.
 
 template<Color Us>
-Score Entry::evaluate_shelter(const Position& pos, Square ksq) {
+Score Entry::evaluate_shelter(const Position& pos, Square ksq) const {
 
   constexpr Color Them = ~Us;