Assorted trivial cleanups 5/2019

No functional change.

bench: 4178282

Readme.md

@@ -1,7 +1,7 @@
 ## Overview
 
 [![Build Status](https://travis-ci.org/official-stockfish/Stockfish.svg?branch=master)](https://travis-ci.org/official-stockfish/Stockfish)
-[![Build Status](https://ci.appveyor.com/api/projects/status/github/official-stockfish/Stockfish?svg=true)](https://ci.appveyor.com/project/mcostalba/stockfish)
+[![Build Status](https://ci.appveyor.com/api/projects/status/github/official-stockfish/Stockfish?branch=master&svg=true)](https://ci.appveyor.com/project/mcostalba/stockfish/branch/master)
 
 [Stockfish](https://stockfishchess.org) is a free, powerful UCI chess engine
 derived from Glaurung 2.1. It is not a complete chess program and requires a
@@ -34,11 +34,11 @@ Currently, Stockfish has the following UCI options:
     A positive value for contempt favors middle game positions and avoids draws.
 
   * #### Analysis Contempt
-    By default, contempt is set to prefer the side to move. Set this option to "White" 
+    By default, contempt is set to prefer the side to move. Set this option to "White"
     or "Black" to analyse with contempt for that side, or "Off" to disable contempt.
 
   * #### Threads
-    The number of CPU threads used for searching a position. For best performance, set 
+    The number of CPU threads used for searching a position. For best performance, set
     this equal to the number of CPU cores available.
 
   * #### Hash
@@ -58,18 +58,18 @@ Currently, Stockfish has the following UCI options:
     Lower the Skill Level in order to make Stockfish play weaker.
 
   * #### Move Overhead
-    Assume a time delay of x ms due to network and GUI overheads. This is useful to 
+    Assume a time delay of x ms due to network and GUI overheads. This is useful to
     avoid losses on time in those cases.
 
   * #### Minimum Thinking Time
-    Search for at least x ms per move. 
+    Search for at least x ms per move.
 
   * #### Slow Mover
-    Lower values will make Stockfish take less time in games, higher values will 
+    Lower values will make Stockfish take less time in games, higher values will
     make it think longer.
 
   * #### nodestime
-    Tells the engine to use nodes searched instead of wall time to account for 
+    Tells the engine to use nodes searched instead of wall time to account for
     elapsed time. Useful for engine testing.
 
   * #### UCI_Chess960
@@ -79,13 +79,13 @@ Currently, Stockfish has the following UCI options:
     An option handled by your GUI.
 
   * #### SyzygyPath
-    Path to the folders/directories storing the Syzygy tablebase files. Multiple 
+    Path to the folders/directories storing the Syzygy tablebase files. Multiple
-    directories are to be separated by ";" on Windows and by ":" on Unix-based 
+    directories are to be separated by ";" on Windows and by ":" on Unix-based
     operating systems. Do not use spaces around the ";" or ":".
-    
+
     Example: `C:\tablebases\wdl345;C:\tablebases\wdl6;D:\tablebases\dtz345;D:\tablebases\dtz6`
-    
+
-    It is recommended to store .rtbw files on an SSD. There is no loss in storing 
+    It is recommended to store .rtbw files on an SSD. There is no loss in storing
     the .rtbz files on a regular HD. It is recommended to verify all md5 checksums
     of the downloaded tablebase files (`md5sum -c checksum.md5`) as corruption will
     lead to engine crashes.
@@ -153,7 +153,7 @@ community effort. There are a few ways to help contribute to its growth.
 ### Donating hardware
 
 Improving Stockfish requires a massive amount of testing. You can donate
-your hardware resources by installing the [Fishtest Worker](https://github.com/glinscott/fishtest/wiki/Running-the-worker) 
+your hardware resources by installing the [Fishtest Worker](https://github.com/glinscott/fishtest/wiki/Running-the-worker)
 and view the current tests on [Fishtest](http://tests.stockfishchess.org/tests).
 
 ### Improving the code
@@ -169,7 +169,7 @@ generic rather than being focused on Stockfish's precise implementation.
 Nevertheless, a helpful resource.
 
 * The latest source can always be found on [GitHub](https://github.com/official-stockfish/Stockfish).
-Discussions about Stockfish take place in the [FishCooking](https://groups.google.com/forum/#!forum/fishcooking) 
+Discussions about Stockfish take place in the [FishCooking](https://groups.google.com/forum/#!forum/fishcooking)
 group and engine testing is done on [Fishtest](http://tests.stockfishchess.org/tests).
 If you want to help improve Stockfish, please read this [guideline](https://github.com/glinscott/fishtest/wiki/Creating-my-first-test)
 first, where the basics of Stockfish development are explained.

src/endgame.cpp

@@ -88,27 +88,28 @@ namespace Endgames {
 
   void init() {
 
-      add<KPK>("KPK");
+    add<KPK>("KPK");
-      add<KNNK>("KNNK");
+    add<KNNK>("KNNK");
-      add<KBNK>("KBNK");
+    add<KBNK>("KBNK");
-      add<KRKP>("KRKP");
+    add<KRKP>("KRKP");
-      add<KRKB>("KRKB");
+    add<KRKB>("KRKB");
-      add<KRKN>("KRKN");
+    add<KRKN>("KRKN");
-      add<KQKP>("KQKP");
+    add<KQKP>("KQKP");
-      add<KQKR>("KQKR");
+    add<KQKR>("KQKR");
-      add<KNNKP>("KNNKP");
+    add<KNNKP>("KNNKP");
 
-      add<KNPK>("KNPK");
+    add<KNPK>("KNPK");
-      add<KNPKB>("KNPKB");
+    add<KNPKB>("KNPKB");
-      add<KRPKR>("KRPKR");
+    add<KRPKR>("KRPKR");
-      add<KRPKB>("KRPKB");
+    add<KRPKB>("KRPKB");
-      add<KBPKB>("KBPKB");
+    add<KBPKB>("KBPKB");
-      add<KBPKN>("KBPKN");
+    add<KBPKN>("KBPKN");
-      add<KBPPKB>("KBPPKB");
+    add<KBPPKB>("KBPPKB");
-      add<KRPPKRP>("KRPPKRP");
+    add<KRPPKRP>("KRPPKRP");
   }
 }
 
+
 /// Mate with KX vs K. This function is used to evaluate positions with
 /// king and plenty of material vs a lone king. It simply gives the
 /// attacking side a bonus for driving the defending king towards the edge

src/endgame.h

@@ -91,7 +91,7 @@ struct Endgame : public EndgameBase<T> {
 };
 
 
-/// The Endgames class stores the pointers to endgame evaluation and scaling
+/// The Endgames namespace handles the pointers to endgame evaluation and scaling
 /// base objects in two std::map. We use polymorphism to invoke the actual
 /// endgame function by calling its virtual operator().
 
@@ -99,9 +99,11 @@ namespace Endgames {
 
   template<typename T> using Ptr = std::unique_ptr<EndgameBase<T>>;
   template<typename T> using Map = std::map<Key, Ptr<T>>;
-  
+
   extern std::pair<Map<Value>, Map<ScaleFactor>> maps;
 
+  void init();
+
   template<typename T>
   Map<T>& map() {
     return std::get<std::is_same<T, ScaleFactor>::value>(maps);
@@ -119,8 +121,6 @@ namespace Endgames {
   const EndgameBase<T>* probe(Key key) {
     return map<T>().count(key) ? map<T>()[key].get() : nullptr;
   }
-
-  void init();
 }
 
 #endif // #ifndef ENDGAME_H_INCLUDED

src/evaluate.cpp

@@ -190,10 +190,8 @@ namespace {
     // color, including x-rays. But diagonal x-rays through pawns are not computed.
     Bitboard attackedBy2[COLOR_NB];
 
-    // kingRing[color] are the squares adjacent to the king, plus (only for a
+    // kingRing[color] are the squares adjacent to the king plus some other
-    // king on its first rank) the squares two ranks in front. For instance,
+    // very near squares, depending on king position.
-    // if black's king is on g8, kingRing[BLACK] is f8, h8, f7, g7, h7, f6, g6
-    // and h6.
     Bitboard kingRing[COLOR_NB];
 
     // kingAttackersCount[color] is the number of pieces of the given color
@@ -802,7 +800,7 @@ namespace {
 
     // Early exit if score is high
     Value v = (mg_value(score) + eg_value(score)) / 2;
-    if (abs(v) > (LazyThreshold + pos.non_pawn_material() / 64))
+    if (abs(v) > LazyThreshold + pos.non_pawn_material() / 64)
        return pos.side_to_move() == WHITE ? v : -v;
 
     // Main evaluation begins here

src/main.cpp

@@ -42,8 +42,8 @@ int main(int argc, char* argv[]) {
   Bitboards::init();
   Position::init();
   Bitbases::init();
-  Search::init();
   Endgames::init();
+  Search::init();
   Threads.set(Options["Threads"]);
   Search::clear(); // After threads are up
 

src/pawns.h

@@ -59,7 +59,6 @@ struct Entry {
   Square kingSquares[COLOR_NB];
   Score kingSafety[COLOR_NB];
   int castlingRights[COLOR_NB];
-  int pawnsOnSquares[COLOR_NB][COLOR_NB]; // [color][light/dark squares]
 };
 
 typedef HashTable<Entry, 16384> Table;

src/position.cpp

@@ -387,7 +387,7 @@ void Position::set_state(StateInfo* si) const {
       if (type_of(pc) == PAWN)
           si->pawnKey ^= Zobrist::psq[pc][s];
 
-      else if (type_of(pc) != PAWN && type_of(pc) != KING)
+      else if (type_of(pc) != KING)
           si->nonPawnMaterial[color_of(pc)] += PieceValue[MG][pc];
   }
 
@@ -491,7 +491,7 @@ Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners
   // Snipers are sliders that attack 's' when a piece and other snipers are removed
   Bitboard snipers = (  (PseudoAttacks[  ROOK][s] & pieces(QUEEN, ROOK))
                       | (PseudoAttacks[BISHOP][s] & pieces(QUEEN, BISHOP))) & sliders;
-  Bitboard occupancy = pieces() & ~snipers;
+  Bitboard occupancy = pieces() ^ snipers;
 
   while (snipers)
   {
@@ -1192,10 +1192,10 @@ bool Position::has_game_cycle(int ply) const {
               if (ply > i)
                   return true;
 
-              // For nodes before or at the root, check that the move is a repetition one
+              // For nodes before or at the root, check that the move is a
-              // rather than a move to the current position.
+              // repetition rather than a move to the current position.
-              // In the cuckoo table, both moves Rc1c5 and Rc5c1 are stored in the same
+              // In the cuckoo table, both moves Rc1c5 and Rc5c1 are stored in
-              // location, so we have to select which square to check.
+              // the same location, so we have to select which square to check.
               if (color_of(piece_on(empty(s1) ? s2 : s1)) != side_to_move())
                   continue;
 

src/search.cpp

@@ -149,7 +149,7 @@ namespace {
 void Search::init() {
 
   for (int i = 1; i < MAX_MOVES; ++i)
-     Reductions[i] = int(22.9 * std::log(i));
+      Reductions[i] = int(22.9 * std::log(i));
 }
 
 
@@ -240,17 +240,13 @@ void MainThread::search() {
           minScore = std::min(minScore, th->rootMoves[0].score);
 
       // Vote according to score and depth, and select the best thread
-      int64_t bestVote = 0;
       for (Thread* th : Threads)
       {
           votes[th->rootMoves[0].pv[0]] +=
-               (th->rootMoves[0].score - minScore + 14) * int(th->completedDepth);
+              (th->rootMoves[0].score - minScore + 14) * int(th->completedDepth);
 
-          if (votes[th->rootMoves[0].pv[0]] > bestVote)
+          if (votes[th->rootMoves[0].pv[0]] > votes[bestThread->rootMoves[0].pv[0]])
-          {
-              bestVote = votes[th->rootMoves[0].pv[0]];
               bestThread = th;
-          }
       }
   }
 
@@ -538,13 +534,13 @@ namespace {
     bool ttHit, ttPv, inCheck, givesCheck, improving;
     bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture;
     Piece movedPiece;
-    int moveCount, captureCount, quietCount;
+    int moveCount, captureCount, quietCount, singularLMR;
 
     // Step 1. Initialize node
     Thread* thisThread = pos.this_thread();
     inCheck = pos.checkers();
     Color us = pos.side_to_move();
-    moveCount = captureCount = quietCount = ss->moveCount = 0;
+    moveCount = captureCount = quietCount = singularLMR = ss->moveCount = 0;
     bestValue = -VALUE_INFINITE;
     maxValue = VALUE_INFINITE;
 
@@ -589,10 +585,10 @@ namespace {
     // starts with statScore = 0. Later grandchildren start with the last calculated
     // statScore of the previous grandchild. This influences the reduction rules in
     // LMR which are based on the statScore of parent position.
-	if (rootNode)
+    if (rootNode)
-		(ss + 4)->statScore = 0;
+        (ss + 4)->statScore = 0;
-	else
+    else
-		(ss + 2)->statScore = 0;
+        (ss + 2)->statScore = 0;
 
     // Step 4. Transposition table lookup. We don't want the score of a partial
     // search to overwrite a previous full search TT value, so we use a different
@@ -850,7 +846,6 @@ moves_loop: // When in check, search starts from here
     value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
     moveCountPruning = false;
     ttCapture = ttMove && pos.capture_or_promotion(ttMove);
-    int singularExtensionLMRmultiplier = 0;
 
     // Step 12. Loop through all pseudo-legal moves until no moves remain
     // or a beta cutoff occurs.
@@ -907,12 +902,13 @@ moves_loop: // When in check, search starts from here
           ss->excludedMove = MOVE_NONE;
 
           if (value < singularBeta)
-              {
+          {
               extension = ONE_PLY;
-              singularExtensionLMRmultiplier++;
+              singularLMR++;
+
               if (value < singularBeta - std::min(3 * depth / ONE_PLY, 39))
-              	  singularExtensionLMRmultiplier++;
+                  singularLMR++;
-              }
+          }
 
           // Multi-cut pruning
           // Our ttMove is assumed to fail high, and now we failed high also on a reduced
@@ -1023,8 +1019,9 @@ moves_loop: // When in check, search starts from here
           // Decrease reduction if opponent's move count is high (~10 Elo)
           if ((ss-1)->moveCount > 15)
               r -= ONE_PLY;
+
           // Decrease reduction if move has been singularly extended
-          r -= singularExtensionLMRmultiplier * ONE_PLY;
+          r -= singularLMR * ONE_PLY;
 
           if (!captureOrPromotion)
           {
@@ -1060,7 +1057,7 @@ moves_loop: // When in check, search starts from here
               r -= ss->statScore / 20000 * ONE_PLY;
           }
 
-          Depth d = std::max(newDepth - std::max(r, DEPTH_ZERO), ONE_PLY);
+          Depth d = clamp(newDepth - r, ONE_PLY, newDepth);
 
           value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
 
@@ -1476,7 +1473,7 @@ moves_loop: // When in check, search starts from here
   void update_capture_stats(const Position& pos, Move move,
                             Move* captures, int captureCount, int bonus) {
 
-      CapturePieceToHistory& captureHistory =  pos.this_thread()->captureHistory;
+      CapturePieceToHistory& captureHistory = pos.this_thread()->captureHistory;
       Piece moved_piece = pos.moved_piece(move);
       PieceType captured = type_of(pos.piece_on(to_sq(move)));
 
@@ -1715,10 +1712,4 @@ void Tablebases::rank_root_moves(Position& pos, Search::RootMoves& rootMoves) {
         if (dtz_available || rootMoves[0].tbScore <= VALUE_DRAW)
             Cardinality = 0;
     }
-    else
-    {
-        // Assign the same rank to all moves
-        for (auto& m : rootMoves)
-            m.tbRank = 0;
-    }
 }

src/search.h

@@ -69,7 +69,7 @@ struct RootMove {
   Value score = -VALUE_INFINITE;
   Value previousScore = -VALUE_INFINITE;
   int selDepth = 0;
-  int tbRank;
+  int tbRank = 0;
   Value tbScore;
   std::vector<Move> pv;
 };

src/tt.cpp

@@ -43,15 +43,16 @@ void TTEntry::save(Key k, Value v, bool pv, Bound b, Depth d, Move m, Value ev)
 
   // Overwrite less valuable entries
   if (  (k >> 48) != key16
-      || d / ONE_PLY + 10 > depth8
+      ||(d - DEPTH_OFFSET) / ONE_PLY > depth8 - 4
       || b == BOUND_EXACT)
   {
+      assert((d - DEPTH_OFFSET) / ONE_PLY >= 0);
+
       key16     = (uint16_t)(k >> 48);
       value16   = (int16_t)v;
       eval16    = (int16_t)ev;
       genBound8 = (uint8_t)(TT.generation8 | uint8_t(pv) << 2 | b);
-      assert((d - DEPTH_NONE) / ONE_PLY >= 0);
+      depth8    = (uint8_t)((d - DEPTH_OFFSET) / ONE_PLY);
-      depth8    = (uint8_t)((d - DEPTH_NONE) / ONE_PLY);
   }
 }
 

src/tt.h

@@ -40,7 +40,7 @@ struct TTEntry {
   Move  move()  const { return (Move )move16; }
   Value value() const { return (Value)value16; }
   Value eval()  const { return (Value)eval16; }
-  Depth depth() const { return (Depth)(depth8 * int(ONE_PLY)) + DEPTH_NONE; }
+  Depth depth() const { return (Depth)(depth8 * int(ONE_PLY)) + DEPTH_OFFSET; }
   bool is_pv() const { return (bool)(genBound8 & 0x4); }
   Bound bound() const { return (Bound)(genBound8 & 0x3); }
   void save(Key k, Value v, bool pv, Bound b, Depth d, Move m, Value ev);

src/types.h

@@ -213,8 +213,9 @@ enum Depth : int {
   DEPTH_QS_NO_CHECKS  = -1 * ONE_PLY,
   DEPTH_QS_RECAPTURES = -5 * ONE_PLY,
 
-  DEPTH_NONE = -6 * ONE_PLY,
+  DEPTH_NONE   = -6 * ONE_PLY,
-  DEPTH_MAX  = MAX_PLY * ONE_PLY
+  DEPTH_OFFSET = DEPTH_NONE,
+  DEPTH_MAX    = MAX_PLY * ONE_PLY
 };
 
 static_assert(!(ONE_PLY & (ONE_PLY - 1)), "ONE_PLY is not a power of 2");