Assorted English grammar changes

No functional change

Resolves #567

Readme.md

@@ -111,4 +111,4 @@ to where the source code can be found. If you make any changes to the
 source code, these changes must also be made available under the GPL.
 
 For full details, read the copy of the GPL found in the file named
-*Copying.txt*
+*Copying.txt*.

src/benchmark.cpp

@@ -166,7 +166,7 @@ void benchmark(const Position& current, istream& is) {
 
   elapsed = now() - elapsed + 1; // Ensure positivity to avoid a 'divide by zero'
 
-  dbg_print(); // Just before to exit
+  dbg_print(); // Just before exiting
 
   cerr << "\n==========================="
        << "\nTotal time (ms) : " << elapsed

src/evaluate.cpp

@@ -33,7 +33,7 @@ namespace {
 
   namespace Trace {
 
-    enum Term { // First 8 entries are for PieceType
+    enum Term { // The first 8 entries are for PieceType
       MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB
     };
 
@@ -89,7 +89,7 @@ namespace {
     // which attack a square in the kingRing of the enemy king.
     int kingAttackersCount[COLOR_NB];
 
-    // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
+    // kingAttackersWeight[color] is the sum of the "weights" of the pieces of the
     // given color which attack a square in the kingRing of the enemy king. The
     // weights of the individual piece types are given by the elements in the
     // KingAttackWeights array.
@@ -161,20 +161,20 @@ namespace {
   const Score RookOnFile[2] = { S(19, 10), S(43, 21) };
 
   // ThreatBySafePawn[PieceType] contains bonuses according to which piece
-  // type is attacked by a pawn which is protected or not attacked.
+  // type is attacked by a pawn which is protected or is not attacked.
   const Score ThreatBySafePawn[PIECE_TYPE_NB] = {
     S(0, 0), S(0, 0), S(176, 139), S(131, 127), S(217, 218), S(203, 215) };
 
   // Threat[by minor/by rook][attacked PieceType] contains
   // bonuses according to which piece type attacks which one.
-  // Attacks on lesser pieces which are pawn defended are not considered.
+  // Attacks on lesser pieces which are pawn-defended are not considered.
   const Score Threat[][PIECE_TYPE_NB] = {
     { S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72,107), S(48,118) }, // by Minor
     { S(0, 0), S(0, 25), S(40, 62), S(40, 59), S( 0, 34), S(35, 48) }  // by Rook
   };
 
   // ThreatByKing[on one/on many] contains bonuses for King attacks on
-  // pawns or pieces which are not pawn defended.
+  // pawns or pieces which are not pawn-defended.
   const Score ThreatByKing[2] = { S(3, 62), S(9, 138) };
 
   // Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns.
@@ -226,7 +226,7 @@ namespace {
   const int KnightCheck       = 14;
 
 
-  // eval_init() initializes king and attack bitboards for given color
+  // eval_init() initializes king and attack bitboards for a given color
   // adding pawn attacks. To be done at the beginning of the evaluation.
 
   template<Color Us>
@@ -319,7 +319,7 @@ namespace {
                 && (pos.pieces(PAWN) & (s + pawn_push(Us))))
                 score += MinorBehindPawn;
 
-            // Penalty for pawns on same color square of bishop
+            // Penalty for pawns on the same color square as the bishop
             if (Pt == BISHOP)
                 score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
 
@@ -352,7 +352,7 @@ namespace {
             if (ei.pi->semiopen_file(Us, file_of(s)))
                 score += RookOnFile[!!ei.pi->semiopen_file(Them, file_of(s))];
 
-            // Penalize when trapped by the king, even more if king cannot castle
+            // Penalize when trapped by the king, even more if the king cannot castle
             else if (mob <= 3)
             {
                 Square ksq = pos.square<KING>(Us);
@@ -368,7 +368,7 @@ namespace {
     if (DoTrace)
         Trace::add(Pt, Us, score);
 
-    // Recursively call evaluate_pieces() of next piece type until KING excluded
+    // Recursively call evaluate_pieces() of next piece type until KING is excluded
     return score - evaluate_pieces<DoTrace, Them, NextPt>(pos, ei, mobility, mobilityArea);
   }
 
@@ -468,7 +468,7 @@ namespace {
         }
 
         // Finally, extract the king danger score from the KingDanger[]
-        // array and subtract the score from evaluation.
+        // array and subtract the score from the evaluation.
         score -= KingDanger[std::max(std::min(attackUnits, 399), 0)];
     }
 
@@ -479,8 +479,8 @@ namespace {
   }
 
 
-  // evaluate_threats() assigns bonuses according to the type of attacking piece
+  // evaluate_threats() assigns bonuses according to the types of the attacking 
-  // and the type of attacked one.
+  // and the attacked pieces.
 
   template<Color Us, bool DoTrace>
   Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
@@ -619,7 +619,7 @@ namespace {
                 // assign a smaller bonus if the block square isn't attacked.
                 int k = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0;
 
-                // If the path to queen is fully defended, assign a big bonus.
+                // If the path to the queen is fully defended, assign a big bonus.
                 // Otherwise assign a smaller bonus if the block square is defended.
                 if (defendedSquares == squaresToQueen)
                     k += 6;
@@ -687,7 +687,7 @@ namespace {
 
 
   // evaluate_initiative() computes the initiative correction value for the
-  // position, i.e. second order bonus/malus based on the known attacking/defending
+  // position, i.e., second order bonus/malus based on the known attacking/defending
   // status of the players.
   Score evaluate_initiative(const Position& pos, int asymmetry, Value eg) {
 
@@ -720,7 +720,7 @@ namespace {
         if (pos.opposite_bishops())
         {
             // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
-            // is almost a draw, in case of KBP vs KB is even more a draw.
+            // is almost a draw, in case of KBP vs KB, it is even more a draw.
             if (   pos.non_pawn_material(WHITE) == BishopValueMg
                 && pos.non_pawn_material(BLACK) == BishopValueMg)
                 sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9);

src/movepick.cpp

@@ -51,7 +51,7 @@ namespace {
 
   // pick_best() finds the best move in the range (begin, end) and moves it to
   // the front. It's faster than sorting all the moves in advance when there
-  // are few moves e.g. the possible captures.
+  // are few moves, e.g., the possible captures.
   Move pick_best(ExtMove* begin, ExtMove* end)
   {
       std::swap(*begin, *std::max_element(begin, end));
@@ -64,12 +64,12 @@ namespace {
 /// Constructors of the MovePicker class. As arguments we pass information
 /// to help it to return the (presumably) good moves first, to decide which
 /// moves to return (in the quiescence search, for instance, we only want to
-/// search captures, promotions and some checks) and how important good move
+/// search captures, promotions, and some checks) and how important good move
 /// ordering is at the current node.
 
 MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
-                       const CounterMovesStats& cmh, Move cm, Search::Stack* s)
+                       const CounterMoveStats& cmh, Move cm, Search::Stack* s)
-           : pos(p), history(h), counterMovesHistory(&cmh), ss(s), countermove(cm), depth(d) {
+           : pos(p), history(h), counterMoveHistory(&cmh), ss(s), countermove(cm), depth(d) {
 
   assert(d > DEPTH_ZERO);
 
@@ -80,7 +80,7 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats&
 
 MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
                        const HistoryStats& h, Square s)
-           : pos(p), history(h), counterMovesHistory(nullptr) {
+           : pos(p), history(h), counterMoveHistory(nullptr) {
 
   assert(d <= DEPTH_ZERO);
 
@@ -105,7 +105,7 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
 }
 
 MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h, Value th)
-           : pos(p), history(h), counterMovesHistory(nullptr), threshold(th) {
+           : pos(p), history(h), counterMoveHistory(nullptr), threshold(th) {
 
   assert(!pos.checkers());
 
@@ -127,9 +127,9 @@ template<>
 void MovePicker::score<CAPTURES>() {
   // Winning and equal captures in the main search are ordered by MVV, preferring
   // captures near our home rank. Surprisingly, this appears to perform slightly
-  // better than SEE based move ordering: exchanging big pieces before capturing
+  // better than SEE-based move ordering: exchanging big pieces before capturing
   // a hanging piece probably helps to reduce the subtree size.
-  // In main search we want to push captures with negative SEE values to the
+  // In the main search we want to push captures with negative SEE values to the
   // badCaptures[] array, but instead of doing it now we delay until the move
   // has been picked up, saving some SEE calls in case we get a cutoff.
   for (auto& m : *this)
@@ -142,14 +142,14 @@ void MovePicker::score<QUIETS>() {
 
   for (auto& m : *this)
       m.value =  history[pos.moved_piece(m)][to_sq(m)]
-               + (*counterMovesHistory)[pos.moved_piece(m)][to_sq(m)];
+               + (*counterMoveHistory)[pos.moved_piece(m)][to_sq(m)];
 }
 
 template<>
 void MovePicker::score<EVASIONS>() {
-  // Try winning and equal captures captures ordered by MVV/LVA, then non-captures
+  // Try winning and equal captures ordered by MVV/LVA, then non-captures ordered
-  // ordered by history value, then bad-captures and quiet moves with a negative
+  // by history value, then bad captures and quiet moves with a negative SEE ordered
-  // SEE ordered by SEE value.
+  // by SEE value.
   Value see;
 
   for (auto& m : *this)
@@ -164,7 +164,7 @@ void MovePicker::score<EVASIONS>() {
 }
 
 
-/// generate_next_stage() generates, scores and sorts the next bunch of moves,
+/// generate_next_stage() generates, scores, and sorts the next bunch of moves
 /// when there are no more moves to try for the current stage.
 
 void MovePicker::generate_next_stage() {

src/movepick.h

@@ -65,10 +65,10 @@ private:
   T table[PIECE_NB][SQUARE_NB];
 };
 
-typedef Stats<Move> MovesStats;
+typedef Stats<Move> MoveStats;
 typedef Stats<Value, false> HistoryStats;
-typedef Stats<Value,  true> CounterMovesStats;
+typedef Stats<Value,  true> CounterMoveStats;
-typedef Stats<CounterMovesStats> CounterMovesHistoryStats;
+typedef Stats<CounterMoveStats> CounterMoveHistoryStats;
 
 
 /// MovePicker class is used to pick one pseudo legal move at a time from the
@@ -85,7 +85,7 @@ public:
 
   MovePicker(const Position&, Move, Depth, const HistoryStats&, Square);
   MovePicker(const Position&, Move, const HistoryStats&, Value);
-  MovePicker(const Position&, Move, Depth, const HistoryStats&, const CounterMovesStats&, Move, Search::Stack*);
+  MovePicker(const Position&, Move, Depth, const HistoryStats&, const CounterMoveStats&, Move, Search::Stack*);
 
   Move next_move();
 
@@ -97,7 +97,7 @@ private:
 
   const Position& pos;
   const HistoryStats& history;
-  const CounterMovesStats* counterMovesHistory;
+  const CounterMoveStats* counterMoveHistory;
   Search::Stack* ss;
   Move countermove;
   Depth depth;

src/search.cpp

@@ -61,7 +61,7 @@ using namespace Search;
 
 namespace {
 
-  // Different node types, used as template parameter
+  // Different node types, used as a template parameter
   enum NodeType { Root, PV, NonPV };
 
   // Razoring and futility margin based on depth
@@ -76,7 +76,7 @@ namespace {
     return Reductions[PvNode][i][std::min(d, 63 * ONE_PLY)][std::min(mn, 63)];
   }
 
-  // Skill struct is used to implement strength limiting
+  // Skill structure is used to implement strength limit
   struct Skill {
     Skill(int l) : level(l) {}
     bool enabled() const { return level < 20; }
@@ -88,8 +88,8 @@ namespace {
     Move best = MOVE_NONE;
   };
 
-  // EasyMoveManager struct is used to detect a so called 'easy move'; when PV is
+  // EasyMoveManager structure is used to detect an 'easy move'. When the PV is
-  // stable across multiple search iterations we can fast return the best move.
+  // stable across multiple search iterations, we can quickly return the best move.
   struct EasyMoveManager {
 
     void clear() {
@@ -106,7 +106,7 @@ namespace {
 
       assert(newPv.size() >= 3);
 
-      // Keep track of how many times in a row 3rd ply remains stable
+      // Keep track of how many times in a row the 3rd ply remains stable
       stableCnt = (newPv[2] == pv[2]) ? stableCnt + 1 : 0;
 
       if (!std::equal(newPv.begin(), newPv.begin() + 3, pv))
@@ -129,7 +129,7 @@ namespace {
 
   EasyMoveManager EasyMove;
   Value DrawValue[COLOR_NB];
-  CounterMovesHistoryStats CounterMovesHistory;
+  CounterMoveHistoryStats CounterMoveHistory;
 
   template <NodeType NT>
   Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
@@ -175,12 +175,12 @@ void Search::init() {
 }
 
 
-/// Search::clear() resets to zero search state, to obtain reproducible results
+/// Search::clear() resets search state to zero, to obtain reproducible results
 
 void Search::clear() {
 
   TT.clear();
-  CounterMovesHistory.clear();
+  CounterMoveHistory.clear();
 
   for (Thread* th : Threads)
   {
@@ -193,7 +193,7 @@ void Search::clear() {
 
 
 /// Search::perft() is our utility to verify move generation. All the leaf nodes
-/// up to the given depth are generated and counted and the sum returned.
+/// up to the given depth are generated and counted, and the sum is returned.
 template<bool Root>
 uint64_t Search::perft(Position& pos, Depth depth) {
 
@@ -223,8 +223,7 @@ template uint64_t Search::perft<true>(Position&, Depth);
 
 
 /// MainThread::search() is called by the main thread when the program receives
-/// the UCI 'go' command. It searches from root position and at the end prints
+/// the UCI 'go' command. It searches from the root position and outputs the "bestmove".
-/// the "bestmove" to output.
 
 void MainThread::search() {
 
@@ -260,8 +259,8 @@ void MainThread::search() {
       if (TB::Cardinality >=  rootPos.count<ALL_PIECES>(WHITE)
                             + rootPos.count<ALL_PIECES>(BLACK))
       {
-          // If the current root position is in the tablebases then RootMoves
+          // If the current root position is in the tablebases, then RootMoves
-          // contains only moves that preserve the draw or win.
+          // contains only moves that preserve the draw or the win.
           TB::RootInTB = Tablebases::root_probe(rootPos, rootMoves, TB::Score);
 
           if (TB::RootInTB)
@@ -269,7 +268,7 @@ void MainThread::search() {
 
           else // If DTZ tables are missing, use WDL tables as a fallback
           {
-              // Filter out moves that do not preserve a draw or win
+              // Filter out moves that do not preserve the draw or the win.
               TB::RootInTB = Tablebases::root_probe_wdl(rootPos, rootMoves, TB::Score);
 
               // Only probe during search if winning
@@ -304,7 +303,7 @@ void MainThread::search() {
   }
 
   // When playing in 'nodes as time' mode, subtract the searched nodes from
-  // the available ones before to exit.
+  // the available ones before exiting.
   if (Limits.npmsec)
       Time.availableNodes += Limits.inc[us] - Threads.nodes_searched();
 
@@ -356,7 +355,7 @@ void MainThread::search() {
 
 // Thread::search() is the main iterative deepening loop. It calls search()
 // repeatedly with increasing depth until the allocated thinking time has been
-// consumed, user stops the search, or the maximum search depth is reached.
+// consumed, the user stops the search, or the maximum search depth is reached.
 
 void Thread::search() {
 
@@ -390,11 +389,11 @@ void Thread::search() {
 
   multiPV = std::min(multiPV, rootMoves.size());
 
-  // Iterative deepening loop until requested to stop or target depth reached
+  // Iterative deepening loop until requested to stop or the target depth is reached.
   while (++rootDepth < DEPTH_MAX && !Signals.stop && (!Limits.depth || rootDepth <= Limits.depth))
   {
-      // Set up the new depth for the helper threads skipping in average each
+      // Set up the new depths for the helper threads skipping on average every
-      // 2nd ply (using a half density map similar to a Hadamard matrix).
+      // 2nd ply (using a half-density map similar to a Hadamard matrix).
       if (!mainThread)
       {
           int d = rootDepth + rootPos.game_ply();
@@ -452,14 +451,14 @@ void Thread::search() {
               // search the already searched PV lines are preserved.
               std::stable_sort(rootMoves.begin() + PVIdx, rootMoves.end());
 
-              // Write PV back to transposition table in case the relevant
+              // Write PV back to the transposition table in case the relevant
               // entries have been overwritten during the search.
               for (size_t i = 0; i <= PVIdx; ++i)
                   rootMoves[i].insert_pv_in_tt(rootPos);
 
-              // If search has been stopped break immediately. Sorting and
+              // If search has been stopped, break immediately. Sorting and
               // writing PV back to TT is safe because RootMoves is still
-              // valid, although it refers to previous iteration.
+              // valid, although it refers to the previous iteration.
               if (Signals.stop)
                   break;
 
@@ -536,8 +535,8 @@ void Thread::search() {
               if (rootDepth > 4 * ONE_PLY && multiPV == 1)
                   Time.pv_instability(mainThread->bestMoveChanges);
 
-              // Stop the search if only one legal move is available or all
+              // Stop the search if only one legal move is available, or if all
-              // of the available time has been used or we matched an easyMove
+              // of the available time has been used, or if we matched an easyMove
               // from the previous search and just did a fast verification.
               if (   rootMoves.size() == 1
                   || Time.elapsed() > Time.available() * ( 640  - 160 * !mainThread->failedLow
@@ -610,7 +609,7 @@ namespace {
     bestValue = -VALUE_INFINITE;
     ss->ply = (ss-1)->ply + 1;
 
-    // Check for available remaining time
+    // Check for the available remaining time
     if (thisThread->resetCalls.load(std::memory_order_relaxed))
     {
         thisThread->resetCalls = false;
@@ -853,7 +852,7 @@ moves_loop: // When in check search starts from here
 
     Square prevSq = to_sq((ss-1)->currentMove);
     Move cm = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq];
-    const CounterMovesStats& cmh = CounterMovesHistory[pos.piece_on(prevSq)][prevSq];
+    const CounterMoveStats& cmh = CounterMoveHistory[pos.piece_on(prevSq)][prevSq];
 
     MovePicker mp(pos, ttMove, depth, thisThread->history, cmh, cm, ss);
     CheckInfo ci(pos);
@@ -1006,9 +1005,10 @@ moves_loop: // When in check search starts from here
                            + cmh[pos.piece_on(to_sq(move))][to_sq(move)]) / 14980;
           r = std::max(DEPTH_ZERO, r - rDecrease * ONE_PLY);
 
-          // Decrease reduction for moves that escape a capture. Filter out castling
+          // Decrease reduction for moves that escape a capture. Filter out
-          // moves because are coded as "king captures rook" and break make_move().
+          // castling moves, because they are coded as "king captures rook" and
-          // Also use see() instead of see_sign() because destination square is empty.
+          // hence break make_move(). Also use see() instead of see_sign(),
+          // because the destination square is empty.
           if (   r
               && type_of(move) == NORMAL
               && type_of(pos.piece_on(to_sq(move))) != PAWN
@@ -1024,7 +1024,7 @@ moves_loop: // When in check search starts from here
       else
           doFullDepthSearch = !PvNode || moveCount > 1;
 
-      // Step 16. Full depth search, when LMR is skipped or fails high
+      // Step 16. Full depth search when LMR is skipped or fails high
       if (doFullDepthSearch)
           value = newDepth <   ONE_PLY ?
                             givesCheck ? -qsearch<NonPV,  true>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
@@ -1033,7 +1033,7 @@ moves_loop: // When in check search starts from here
 
       // For PV nodes only, do a full PV search on the first move or after a fail
       // high (in the latter case search only if value < beta), otherwise let the
-      // parent node fail low with value <= alpha and to try another move.
+      // parent node fail low with value <= alpha and try another move.
       if (PvNode && (moveCount == 1 || (value > alpha && (RootNode || value < beta))))
       {
           (ss+1)->pv = pv;
@@ -1050,7 +1050,7 @@ moves_loop: // When in check search starts from here
 
       assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
 
-      // Step 18. Check for new best move
+      // Step 18. Check for a new best move
       // Finished searching the move. If a stop occurred, the return value of
       // the search cannot be trusted, and we return immediately without
       // updating best move, PV and TT.
@@ -1118,7 +1118,7 @@ moves_loop: // When in check search starts from here
           quietsSearched[quietCount++] = move;
     }
 
-    // Following condition would detect a stop only after move loop has been
+    // The following condition would detect a stop only after move loop has been
     // completed. But in this case bestValue is valid because we have fully
     // searched our subtree, and we can anyhow save the result in TT.
     /*
@@ -1128,7 +1128,7 @@ moves_loop: // When in check search starts from here
 
     // Step 20. Check for mate and stalemate
     // All legal moves have been searched and if there are no legal moves, it
-    // must be mate or stalemate. If we are in a singular extension search then
+    // must be a mate or a stalemate. If we are in a singular extension search then
     // return a fail low score.
     if (!moveCount)
         bestValue = excludedMove ? alpha
@@ -1148,7 +1148,7 @@ moves_loop: // When in check search starts from here
     {
         Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + depth / ONE_PLY - 1);
         Square prevPrevSq = to_sq((ss - 2)->currentMove);
-        CounterMovesStats& prevCmh = CounterMovesHistory[pos.piece_on(prevPrevSq)][prevPrevSq];
+        CounterMoveStats& prevCmh = CounterMoveHistory[pos.piece_on(prevPrevSq)][prevPrevSq];
         prevCmh.update(pos.piece_on(prevSq), prevSq, bonus);
     }
 
@@ -1334,7 +1334,7 @@ moves_loop: // When in check search starts from here
 
       assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
 
-      // Check for new best move
+      // Check for a new best move
       if (value > bestValue)
       {
           bestValue = value;
@@ -1425,7 +1425,7 @@ moves_loop: // When in check search starts from here
     Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + depth / ONE_PLY - 1);
 
     Square prevSq = to_sq((ss-1)->currentMove);
-    CounterMovesStats& cmh = CounterMovesHistory[pos.piece_on(prevSq)][prevSq];
+    CounterMoveStats& cmh = CounterMoveHistory[pos.piece_on(prevSq)][prevSq];
     Thread* thisThread = pos.this_thread();
 
     thisThread->history.update(pos.moved_piece(move), to_sq(move), bonus);
@@ -1451,7 +1451,7 @@ moves_loop: // When in check search starts from here
         && is_ok((ss-2)->currentMove))
     {
         Square prevPrevSq = to_sq((ss-2)->currentMove);
-        CounterMovesStats& prevCmh = CounterMovesHistory[pos.piece_on(prevPrevSq)][prevPrevSq];
+        CounterMoveStats& prevCmh = CounterMoveHistory[pos.piece_on(prevPrevSq)][prevPrevSq];
         prevCmh.update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY);
     }
   }
@@ -1472,8 +1472,8 @@ moves_loop: // When in check search starts from here
     int maxScore = -VALUE_INFINITE;
 
     // Choose best move. For each move score we add two terms, both dependent on
-    // weakness. One deterministic and bigger for weaker levels, and one random,
+    // weakness. One is deterministic and bigger for weaker levels, and one is 
-    // then we choose the move with the resulting highest score.
+    // random. Then we choose the move with the resulting highest score.
     for (size_t i = 0; i < multiPV; ++i)
     {
         // This is our magic formula
@@ -1603,7 +1603,7 @@ void RootMove::insert_pv_in_tt(Position& pos) {
 
 
 /// RootMove::extract_ponder_from_tt() is called in case we have no ponder move
-/// before exiting the search, for instance in case we stop the search during a
+/// before exiting the search, for instance, in case we stop the search during a
 /// fail high at root. We try hard to have a ponder move to return to the GUI,
 /// otherwise in case of 'ponder on' we have nothing to think on.
 

src/syzygy/tbcore.cpp

@@ -3,7 +3,7 @@
   This file may be redistributed and/or modified without restrictions.
 
   tbcore.c contains engine-independent routines of the tablebase probing code.
-  This file should not need to much adaptation to add tablebase probing to
+  This file should not need too much adaptation to add tablebase probing to
   a particular engine, provided the engine is written in C or C++.
 */
 

src/thread.cpp

@@ -30,7 +30,7 @@ using namespace Search;
 
 ThreadPool Threads; // Global object
 
-/// Thread constructor launch the thread and then wait until it goes to sleep
+/// Thread constructor launches the thread and then waits until it goes to sleep
 /// in idle_loop().
 
 Thread::Thread() {
@@ -48,7 +48,7 @@ Thread::Thread() {
 }
 
 
-/// Thread destructor wait for thread termination before returning
+/// Thread destructor waits for thread termination before returning
 
 Thread::~Thread() {
 
@@ -60,7 +60,8 @@ Thread::~Thread() {
 }
 
 
-/// Thread::wait_for_search_finished() wait on sleep condition until not searching
+/// Thread::wait_for_search_finished() waits on sleep condition
+/// until not searching
 
 void Thread::wait_for_search_finished() {
 
@@ -69,7 +70,7 @@ void Thread::wait_for_search_finished() {
 }
 
 
-/// Thread::wait() wait on sleep condition until condition is true
+/// Thread::wait() waits on sleep condition until condition is true
 
 void Thread::wait(std::atomic_bool& condition) {
 
@@ -78,7 +79,7 @@ void Thread::wait(std::atomic_bool& condition) {
 }
 
 
-/// Thread::start_searching() wake up the thread that will start the search
+/// Thread::start_searching() wakes up the thread that will start the search
 
 void Thread::start_searching(bool resume) {
 
@@ -115,7 +116,7 @@ void Thread::idle_loop() {
 }
 
 
-/// ThreadPool::init() create and launch requested threads, that will go
+/// ThreadPool::init() creates and launches requested threads that will go
 /// immediately to sleep. We cannot use a constructor because Threads is a
 /// static object and we need a fully initialized engine at this point due to
 /// allocation of Endgames in the Thread constructor.
@@ -127,9 +128,9 @@ void ThreadPool::init() {
 }
 
 
-/// ThreadPool::exit() terminate threads before the program exits. Cannot be
+/// ThreadPool::exit() terminates threads before the program exits. Cannot be
 /// done in destructor because threads must be terminated before deleting any
-/// static objects, so while still in main().
+/// static objects while still in main().
 
 void ThreadPool::exit() {
 
@@ -156,7 +157,7 @@ void ThreadPool::read_uci_options() {
 }
 
 
-/// ThreadPool::nodes_searched() return the number of nodes searched
+/// ThreadPool::nodes_searched() returns the number of nodes searched
 
 int64_t ThreadPool::nodes_searched() {
 
@@ -167,8 +168,8 @@ int64_t ThreadPool::nodes_searched() {
 }
 
 
-/// ThreadPool::start_thinking() wake up the main thread sleeping in idle_loop()
+/// ThreadPool::start_thinking() wakes up the main thread sleeping in idle_loop()
-/// and start a new search, then return immediately.
+/// and starts a new search, then returns immediately.
 
 void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
                                 StateStackPtr& states) {

src/thread.h

@@ -36,7 +36,7 @@
 #include "thread_win32.h"
 
 
-/// Thread struct keeps together all the thread related stuff. We also use
+/// Thread struct keeps together all the thread-related stuff. We also use
 /// per-thread pawn and material hash tables so that once we get a pointer to an
 /// entry its life time is unlimited and we don't have to care about someone
 /// changing the entry under our feet.
@@ -67,7 +67,7 @@ public:
   Search::RootMoveVector rootMoves;
   Depth rootDepth;
   HistoryStats history;
-  MovesStats counterMoves;
+  MoveStats counterMoves;
   Depth completedDepth;
   std::atomic_bool resetCalls;
 };
@@ -84,7 +84,7 @@ struct MainThread : public Thread {
 };
 
 
-/// ThreadPool struct handles all the threads related stuff like init, starting,
+/// ThreadPool struct handles all the threads-related stuff like init, starting,
 /// parking and, most importantly, launching a thread. All the access to threads
 /// data is done through this class.
 

src/thread_win32.h

@@ -25,11 +25,11 @@
 /// relies on libwinpthread. Currently libwinpthread implements mutexes directly
 /// on top of Windows semaphores. Semaphores, being kernel objects, require kernel
 /// mode transition in order to lock or unlock, which is very slow compared to
-/// interlocked operations (about 30% slower on bench test). To workaround this
+/// interlocked operations (about 30% slower on bench test). To work around this
 /// issue, we define our wrappers to the low level Win32 calls. We use critical
 /// sections to support Windows XP and older versions. Unfortunately, cond_wait()
 /// is racy between unlock() and WaitForSingleObject() but they have the same
-/// speed performance of SRW locks.
+/// speed performance as the SRW locks.
 
 #include <condition_variable>
 #include <mutex>

src/timeman.cpp

@@ -40,7 +40,7 @@ namespace {
   // move_importance() is a skew-logistic function based on naive statistical
   // analysis of "how many games are still undecided after n half-moves". Game
   // is considered "undecided" as long as neither side has >275cp advantage.
-  // Data was extracted from CCRL game database with some simple filtering criteria.
+  // Data was extracted from the CCRL game database with some simple filtering criteria.
 
   double move_importance(int ply) {
 
@@ -66,7 +66,7 @@ namespace {
     double ratio1 = (TMaxRatio * moveImportance) / (TMaxRatio * moveImportance + otherMovesImportance);
     double ratio2 = (moveImportance + TStealRatio * otherMovesImportance) / (moveImportance + otherMovesImportance);
 
-    return int(myTime * std::min(ratio1, ratio2)); // Intel C++ asks an explicit cast
+    return int(myTime * std::min(ratio1, ratio2)); // Intel C++ asks for an explicit cast
   }
 
 } // namespace
@@ -91,7 +91,7 @@ void TimeManagement::init(Search::LimitsType& limits, Color us, int ply)
   // If we have to play in 'nodes as time' mode, then convert from time
   // to nodes, and use resulting values in time management formulas.
   // WARNING: Given npms (nodes per millisecond) must be much lower then
-  // real engine speed to avoid time losses.
+  // the real engine speed to avoid time losses.
   if (npmsec)
   {
       if (!availableNodes) // Only once at game start