Extend discovered checks regardless of SEE

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 75b94c19c0d012e1a00e7e3abc98d644afb4072b..c581c8e72e90fa7ef4ac64408b1fa56405b1d21b 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.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) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 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
@@ -58,10 +58,6 @@ namespace {
     { V(-10), V(-14), V( 90), V(15), V( 2), V( -7), V(-16) }
   };
 
-  // Danger of blocked enemy pawns storming our king, by rank
-  constexpr Value BlockedStorm[RANK_NB] =
-    { V(0), V(0), V(66), V(6), V(5), V(1), V(15) };
-
   #undef S
   #undef V
 
@@ -71,7 +67,7 @@ namespace {
     constexpr Color     Them = (Us == WHITE ? BLACK : WHITE);
     constexpr Direction Up   = (Us == WHITE ? NORTH : SOUTH);
 
-    Bitboard b, neighbours, stoppers, doubled, supported, phalanx;
+    Bitboard b, neighbours, stoppers, doubled, support, phalanx;
     Bitboard lever, leverPush;
     Square s;
     bool opposed, backward;
@@ -106,7 +102,7 @@ namespace {
         doubled    = ourPawns   & (s - Up);
         neighbours = ourPawns   & adjacent_files_bb(f);
         phalanx    = neighbours & rank_bb(s);
-        supported  = neighbours & rank_bb(s - Up);
+        support    = neighbours & rank_bb(s - Up);
 
         // A pawn is backward when it is behind all pawns of the same color
         // on the adjacent files and cannot be safely advanced.
@@ -118,22 +114,22 @@ namespace {
         // which could become passed after one or two pawn pushes when are
         // not attacked more times than defended.
         if (   !(stoppers ^ lever ^ leverPush)
-            && popcount(supported) >= popcount(lever) - 1
-            && popcount(phalanx)   >= popcount(leverPush))
+            && popcount(support) >= popcount(lever) - 1
+            && popcount(phalanx) >= popcount(leverPush))
             e->passedPawns[Us] |= s;
 
         else if (   stoppers == SquareBB[s + Up]
                  && relative_rank(Us, s) >= RANK_5)
         {
-            b = shift<Up>(supported) & ~theirPawns;
+            b = shift<Up>(support) & ~theirPawns;
             while (b)
                 if (!more_than_one(theirPawns & PawnAttacks[Us][pop_lsb(&b)]))
                     e->passedPawns[Us] |= s;
         }
 
         // Score this pawn
-        if (supported | phalanx)
-            score += Connected[opposed][bool(phalanx)][popcount(supported)][relative_rank(Us, s)];
+        if (support | phalanx)
+            score += Connected[opposed][bool(phalanx)][popcount(support)][relative_rank(Us, s)];
 
         else if (!neighbours)
             score -= Isolated, e->weakUnopposed[Us] += !opposed;
@@ -141,7 +137,7 @@ namespace {
         else if (backward)
             score -= Backward, e->weakUnopposed[Us] += !opposed;
 
-        if (doubled && !supported)
+        if (doubled && !support)
             score -= Doubled;
     }
 
@@ -189,7 +185,6 @@ Entry* probe(const Position& pos) {
   e->key = key;
   e->scores[WHITE] = evaluate<WHITE>(pos, e);
   e->scores[BLACK] = evaluate<BLACK>(pos, e);
-  e->openFiles = popcount(e->semiopenFiles[WHITE] & e->semiopenFiles[BLACK]);
   e->asymmetry = popcount(  (e->passedPawns[WHITE]   | e->passedPawns[BLACK])
                           | (e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]));
 
@@ -218,14 +213,14 @@ Value Entry::evaluate_shelter(const Position& pos, Square ksq) {
   for (File f = File(center - 1); f <= File(center + 1); ++f)
   {
       b = ourPawns & file_bb(f);
-      int ourRank = b ? relative_rank(Us, backmost_sq(Us, b)) : 0;
+      Rank ourRank = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
 
       b = theirPawns & file_bb(f);
-      int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
+      Rank theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
 
       int d = std::min(f, ~f);
       safety += ShelterStrength[d][ourRank];
-      safety -= (ourRank && (ourRank == theirRank - 1)) ? BlockedStorm[theirRank]
+      safety -= (ourRank && (ourRank == theirRank - 1)) ? 66 * (theirRank == RANK_3)
                                                         : UnblockedStorm[d][theirRank];
   }
 
@@ -237,10 +232,11 @@ Value Entry::evaluate_shelter(const Position& pos, Square ksq) {
 /// when king square changes, which is about 20% of total king_safety() calls.
 
 template<Color Us>
-Score Entry::do_king_safety(const Position& pos, Square ksq) {
+Score Entry::do_king_safety(const Position& pos) {
 
+  Square ksq = pos.square<KING>(Us);
   kingSquares[Us] = ksq;
-  castlingRights[Us] = pos.can_castle(Us);
+  castlingRights[Us] = pos.castling_rights(Us);
   int minKingPawnDistance = 0;
 
   Bitboard pawns = pos.pieces(Us, PAWN);
@@ -250,17 +246,17 @@ Score Entry::do_king_safety(const Position& pos, Square ksq) {
   Value bonus = evaluate_shelter<Us>(pos, ksq);
 
   // If we can castle use the bonus after the castling if it is bigger
-  if (pos.can_castle(MakeCastling<Us, KING_SIDE>::right))
+  if (pos.can_castle(Us | KING_SIDE))
       bonus = std::max(bonus, evaluate_shelter<Us>(pos, relative_square(Us, SQ_G1)));
 
-  if (pos.can_castle(MakeCastling<Us, QUEEN_SIDE>::right))
+  if (pos.can_castle(Us | QUEEN_SIDE))
       bonus = std::max(bonus, evaluate_shelter<Us>(pos, relative_square(Us, SQ_C1)));
 
   return make_score(bonus, -16 * minKingPawnDistance);
 }
 
 // Explicit template instantiation
-template Score Entry::do_king_safety<WHITE>(const Position& pos, Square ksq);
-template Score Entry::do_king_safety<BLACK>(const Position& pos, Square ksq);
+template Score Entry::do_king_safety<WHITE>(const Position& pos);
+template Score Entry::do_king_safety<BLACK>(const Position& pos);
 
 } // namespace Pawns