Remove semiopenFiles in pawns and simplify space #2102

This is a functional simplification.

    1. semiopenFiles is removed in pawns and uses the piece arrays in position instead.

    2. popcount is removed in space calculations and uses pawn piece count instead.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 33327 W: 7423 L: 7324 D: 18580
http://tests.stockfishchess.org/tests/view/5cb4be090ebc5925cf018511

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 10173 W: 1774 L: 1636 D: 6763
http://tests.stockfishchess.org/tests/view/5cb4c5920ebc5925cf018696

bench 3402947

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 7408a77ccf0236c02dab1608399d7311901594c5..fbe768bbbd4d72983fd1abd312ec7c31ba881c58 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -358,8 +358,8 @@ namespace {
                 score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]);
 
             // Bonus for rook on an open or semi-open file
-            if (pe->semiopen_file(Us, file_of(s)))
-                score += RookOnFile[bool(pe->semiopen_file(Them, file_of(s)))];
+            if (pos.semiopen_file(Us, file_of(s)))
+                score += RookOnFile[bool(pos.semiopen_file(Them, file_of(s)))];
 
             // Penalty when trapped by the king, even more if the king cannot castle
             else if (mob <= 3)
@@ -720,7 +720,7 @@ namespace {
 
     int bonus = popcount(safe) + popcount(behind & safe);
     int weight =  pos.count<ALL_PIECES>(Us)
-                - 2 * popcount(pe->semiopenFiles[WHITE] & pe->semiopenFiles[BLACK]);
+               - (16 - pos.count<PAWN>()) / 4;
 
     Score score = make_score(bonus * weight * weight / 16, 0);
 

diff --git a/src/pawns.cpp b/src/pawns.cpp
index b034f478bede4e4456bd4ee3c741992c2ef6ef5d..7e29f5065803cc7b7d801f6935dd15903db27aef 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -77,7 +77,6 @@ namespace {
     Bitboard theirPawns = pos.pieces(Them, PAWN);
 
     e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0;
-    e->semiopenFiles[Us] = 0xFF;
     e->kingSquares[Us]   = SQ_NONE;
     e->pawnAttacks[Us]   = pawn_attacks_bb<Us>(ourPawns);
     e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares);
@@ -91,7 +90,6 @@ namespace {
         File f = file_of(s);
         Rank r = relative_rank(Us, s);
 
-        e->semiopenFiles[Us]   &= ~(1 << f);
         e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s);
 
         // Flag the pawn

diff --git a/src/pawns.h b/src/pawns.h
index 71d18ee899e1c1507a59800d341594d23fd5de50..5f5411f613a5e5cc6f9644315cb89b9595fbbe5e 100644 (file)
--- a/src/pawns.h
+++ b/src/pawns.h
@@ -40,10 +40,6 @@ struct Entry {
   int weak_unopposed(Color c) const { return weakUnopposed[c]; }
   int passed_count() const { return passedCount; }
 
-  int semiopen_file(Color c, File f) const {
-    return semiopenFiles[c] & (1 << f);
-  }
-
   int pawns_on_same_color_squares(Color c, Square s) const {
     return pawnsOnSquares[c][bool(DarkSquares & s)];
   }
@@ -69,7 +65,6 @@ struct Entry {
   Score kingSafety[COLOR_NB];
   int weakUnopposed[COLOR_NB];
   int castlingRights[COLOR_NB];
-  int semiopenFiles[COLOR_NB];
   int pawnsOnSquares[COLOR_NB][COLOR_NB]; // [color][light/dark squares]
   int passedCount;
 };

diff --git a/src/position.h b/src/position.h
index 03c00148a084636fbeac4370f55635890ec0c46f..1351d0d125a6b60a4d14d78aaf071af638417b92 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -95,6 +95,7 @@ public:
   template<PieceType Pt> int count() const;
   template<PieceType Pt> const Square* squares(Color c) const;
   template<PieceType Pt> Square square(Color c) const;
+  int semiopen_file(Color c, File f) const;
 
   // Castling
   int castling_rights(Color c) const;
@@ -260,6 +261,10 @@ inline Square Position::ep_square() const {
   return st->epSquare;
 }
 
+inline int Position::semiopen_file(Color c, File f) const {
+  return !(pieces(c, PAWN) & file_bb(f));
+}
+
 inline bool Position::can_castle(CastlingRight cr) const {
   return st->castlingRights & cr;
 }