Implement bestValue in root_search.

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 2b41ec448da40db166b8a107e7a529ddc0a491e1..6aa13a5e84573ecfb6a3c5c1ecdecface8e72e67 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -47,6 +47,60 @@ namespace {
 
   /// Types
 
 
   /// Types
 

+  //The IterationInfoType is used to store search history
+  //iteration by iteration.
+  //
+  //Because we use relatively small (dynamic) aspiration window,
+  //there happens many fail highs and fail lows in root. And
+  //because we don't do researches in those cases, "value" stored
+  //here is not necessarily exact. Instead in case of fail high/low
+  //we guess what the right value might be and store our guess
+  //as "speculated value" and then move on...
+
+  class IterationInfoType {
+    private:
+      Value _value;
+      Value _speculatedValue;
+      bool _failHigh;
+      bool _failLow;
+    public:
+      IterationInfoType() {
+        clear();
+      }
+
+      inline void clear() {
+        set(Value(0));
+      }
+
+      inline void set(Value v) {
+        set(v, v, false, false);
+      }
+
+      inline void set(Value v, Value specV, bool fHigh, bool fLow) {
+        _value = v;
+        _speculatedValue = specV;
+        _failHigh = fHigh;
+        _failLow = fLow;
+      }
+
+      inline Value value() {
+        return _value;
+      }
+
+      inline Value speculated_value() {
+        return _speculatedValue;
+      }
+
+      inline bool fail_high() {
+        return _failHigh;
+      }
+
+      inline bool fail_low() {
+        return _failLow;
+      }
+  };
+
+

   // The BetaCounterType class is used to order moves at ply one.
   // Apart for the first one that has its score, following moves
   // normally have score -VALUE_INFINITE, so are ordered according
   // The BetaCounterType class is used to order moves at ply one.
   // Apart for the first one that has its score, following moves
   // normally have score -VALUE_INFINITE, so are ordered according


@@ -125,9 +179,6 @@ namespace {
   const bool UseIIDAtPVNodes = true;
   const bool UseIIDAtNonPVNodes = false;
 
   const bool UseIIDAtPVNodes = true;
   const bool UseIIDAtNonPVNodes = false;
 

-  // Use null move driven internal iterative deepening?
-  bool UseNullDrivenIID = false;
-

   // Internal iterative deepening margin.  At Non-PV moves, when
   // UseIIDAtNonPVNodes is true, we do an internal iterative deepening search
   // when the static evaluation is at most IIDMargin below beta.
   // Internal iterative deepening margin.  At Non-PV moves, when
   // UseIIDAtNonPVNodes is true, we do an internal iterative deepening search
   // when the static evaluation is at most IIDMargin below beta.


@@ -196,11 +247,10 @@ namespace {
 
   // Iteration counters
   int Iteration;
 
   // Iteration counters
   int Iteration;

-  bool LastIterations;

   BetaCounterType BetaCounter;
 
   // Scores and number of times the best move changed for each iteration:
   BetaCounterType BetaCounter;
 
   // Scores and number of times the best move changed for each iteration:

-  Value ValueByIteration[PLY_MAX_PLUS_2];
+  IterationInfoType IterationInfo[PLY_MAX_PLUS_2];

   int BestMoveChangesByIteration[PLY_MAX_PLUS_2];
 
   // MultiPV mode
   int BestMoveChangesByIteration[PLY_MAX_PLUS_2];
 
   // MultiPV mode


@@ -210,7 +260,7 @@ namespace {
   int SearchStartTime;
   int MaxNodes, MaxDepth;
   int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime;
   int SearchStartTime;
   int MaxNodes, MaxDepth;
   int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime;

-  Move BestRootMove, PonderMove, EasyMove;
+  Move EasyMove;

   int RootMoveNumber;
   bool InfiniteSearch;
   bool PonderSearch;
   int RootMoveNumber;
   bool InfiniteSearch;
   bool PonderSearch;


@@ -218,6 +268,7 @@ namespace {
   bool AbortSearch;
   bool Quit;
   bool FailHigh;
   bool AbortSearch;
   bool Quit;
   bool FailHigh;

+  bool FailLow;

   bool Problem;
   bool PonderingEnabled;
   int ExactMaxTime;
   bool Problem;
   bool PonderingEnabled;
   int ExactMaxTime;


@@ -250,7 +301,8 @@ namespace {
   /// Functions
 
   Value id_loop(const Position &pos, Move searchMoves[]);
   /// Functions
 
   Value id_loop(const Position &pos, Move searchMoves[]);

-  Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml);
+  Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml,
+                    Value alpha, Value beta);

   Value search_pv(Position &pos, SearchStack ss[], Value alpha, Value beta,
                   Depth depth, int ply, int threadID);
   Value search(Position &pos, SearchStack ss[], Value beta,
   Value search_pv(Position &pos, SearchStack ss[], Value alpha, Value beta,
                   Depth depth, int ply, int threadID);
   Value search(Position &pos, SearchStack ss[], Value beta,


@@ -259,9 +311,7 @@ namespace {
                 Depth depth, int ply, int threadID);
   void sp_search(SplitPoint *sp, int threadID);
   void sp_search_pv(SplitPoint *sp, int threadID);
                 Depth depth, int ply, int threadID);
   void sp_search(SplitPoint *sp, int threadID);
   void sp_search_pv(SplitPoint *sp, int threadID);

-  void init_search_stack(SearchStack& ss);
-  void init_search_stack(SearchStack ss[]);
-  void init_node(const Position &pos, SearchStack ss[], int ply, int threadID);
+  void init_node(SearchStack ss[], int ply, int threadID);

   void update_pv(SearchStack ss[], int ply);
   void sp_update_pv(SearchStack *pss, SearchStack ss[], int ply);
   bool connected_moves(const Position &pos, Move m1, Move m2);
   void update_pv(SearchStack ss[], int ply);
   void sp_update_pv(SearchStack *pss, SearchStack ss[], int ply);
   bool connected_moves(const Position &pos, Move m1, Move m2);


@@ -290,8 +340,8 @@ namespace {
   bool thread_is_available(int slave, int master);
   bool idle_thread_exists(int master);
   bool split(const Position &pos, SearchStack *ss, int ply,
   bool thread_is_available(int slave, int master);
   bool idle_thread_exists(int master);
   bool split(const Position &pos, SearchStack *ss, int ply,

-             Value *alpha, Value *beta, Value *bestValue, Depth depth,
-             int *moves, MovePicker *mp, int master, bool pvNode);
+             Value *alpha, Value *beta, Value *bestValue, Depth depth, int *moves,
+             MovePicker *mp, Bitboard dcCandidates, int master, bool pvNode);

   void wake_sleeping_threads();
 
 #if !defined(_MSC_VER)
   void wake_sleeping_threads();
 
 #if !defined(_MSC_VER)


@@ -324,6 +374,23 @@ History H;  // Should be made local?
 SearchStack EmptySearchStack;
 
 
 SearchStack EmptySearchStack;
 
 

+// SearchStack::init() initializes a search stack. Used at the beginning of a
+// new search from the root.
+void SearchStack::init(int ply) {
+
+  pv[ply] = pv[ply + 1] = MOVE_NONE;
+  currentMove = threatMove = MOVE_NONE;
+  reduction = Depth(0);
+}
+
+void SearchStack::initKillers() {
+
+  mateKiller = MOVE_NONE;
+  for (int i = 0; i < KILLER_MAX; i++)
+      killers[i] = MOVE_NONE;
+}
+
+

 ////
 //// Functions
 ////
 ////
 //// Functions
 ////


@@ -356,8 +423,6 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
   // Initialize global search variables
   Idle = false;
   SearchStartTime = get_system_time();
   // Initialize global search variables
   Idle = false;
   SearchStartTime = get_system_time();

-  BestRootMove = MOVE_NONE;
-  PonderMove = MOVE_NONE;

   EasyMove = MOVE_NONE;
   for (int i = 0; i < THREAD_MAX; i++)
   {
   EasyMove = MOVE_NONE;
   for (int i = 0; i < THREAD_MAX; i++)
   {


@@ -371,6 +436,7 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
   AbortSearch = false;
   Quit = false;
   FailHigh = false;
   AbortSearch = false;
   Quit = false;
   FailHigh = false;

+  FailLow = false;

   Problem = false;
   ExactMaxTime = maxTime;
 
   Problem = false;
   ExactMaxTime = maxTime;
 


@@ -411,7 +477,6 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
   if (UseLogFile)
       LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
 
   if (UseLogFile)
       LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
 

-  UseNullDrivenIID = get_option_value_bool("Null driven IID");

   UseQSearchFutilityPruning = get_option_value_bool("Futility Pruning (Quiescence Search)");
   UseFutilityPruning = get_option_value_bool("Futility Pruning (Main Search)");
 
   UseQSearchFutilityPruning = get_option_value_bool("Futility Pruning (Quiescence Search)");
   UseFutilityPruning = get_option_value_bool("Futility Pruning (Main Search)");
 


@@ -588,7 +653,8 @@ void init_threads() {
   }
 
   // Init also the empty search stack
   }
 
   // Init also the empty search stack

-  init_search_stack(EmptySearchStack);
+  EmptySearchStack.init(0);
+  EmptySearchStack.initKillers();

 }
 
 
 }
 
 


@@ -640,17 +706,18 @@ namespace {
     // Initialize
     TT.new_search();
     H.clear();
     // Initialize
     TT.new_search();
     H.clear();

-    init_search_stack(ss);
-
-    ValueByIteration[0] = Value(0);
-    ValueByIteration[1] = rml.get_move_score(0);
+    for (int i = 0; i < 3; i++)
+    {
+        ss[i].init(i);
+        ss[i].initKillers();
+    }
+    IterationInfo[1].set(rml.get_move_score(0));

     Iteration = 1;
     Iteration = 1;

-    LastIterations = false;

 
     EasyMove = rml.scan_for_easy_move();
 
     // Iterative deepening loop
 
     EasyMove = rml.scan_for_easy_move();
 
     // Iterative deepening loop

-    while (!AbortSearch && Iteration < PLY_MAX)
+    while (Iteration < PLY_MAX)

     {
         // Initialize iteration
         rml.sort();
     {
         // Initialize iteration
         rml.sort();


@@ -661,8 +728,59 @@ namespace {
 
         std::cout << "info depth " << Iteration << std::endl;
 
 
         std::cout << "info depth " << Iteration << std::endl;
 

+        //Calculate dynamic search window based on previous iterations.
+        Value alpha;
+        Value beta;
+
+        if (MultiPV == 1 && Iteration >= 6) {
+          Value prevDelta1 = IterationInfo[Iteration - 1].speculated_value() - IterationInfo[Iteration - 2].speculated_value();
+          Value prevDelta2 = IterationInfo[Iteration - 2].speculated_value() - IterationInfo[Iteration - 3].speculated_value();
+
+          Value delta = Max((2 * Abs(prevDelta1) + Abs(prevDelta2)) , ProblemMargin);
+
+          alpha = IterationInfo[Iteration - 1].value() - delta;
+          beta  = IterationInfo[Iteration - 1].value() + delta;
+          if (alpha < - VALUE_INFINITE) alpha = - VALUE_INFINITE;
+          if (beta  >   VALUE_INFINITE) beta = VALUE_INFINITE;
+
+        } else {
+          alpha = - VALUE_INFINITE;
+          beta  =   VALUE_INFINITE;
+        }
+

         // Search to the current depth
         // Search to the current depth

-        ValueByIteration[Iteration] = root_search(p, ss, rml);
+        Value value = root_search(p, ss, rml, alpha, beta);
+        if (AbortSearch)
+          break; //Value cannot be trusted. Break out immediately!
+
+        // Write PV to transposition table, in case the relevant entries have
+        // been overwritten during the search:
+        TT.insert_pv(p, ss[0].pv);
+
+        //Save info about search result
+        Value speculated_value = value;
+        bool fHigh = false;
+        bool fLow = false;
+
+        Value prev_value = IterationInfo[Iteration - 1].value();
+        Value delta = value - prev_value;
+
+        if (value >= beta) {
+          fHigh = true;
+          speculated_value = prev_value + 2 * delta;
+          BestMoveChangesByIteration[Iteration] += 2; //This is used to tell time management to allocate more time
+        } else if (value <= alpha) {
+          fLow = true;
+          speculated_value = prev_value + 2 * delta;
+          BestMoveChangesByIteration[Iteration] += 3; //This is used to tell time management to allocate more time
+        } else {
+          //nothing
+        }
+
+        if (speculated_value < - VALUE_INFINITE) speculated_value = - VALUE_INFINITE;
+        if (speculated_value >   VALUE_INFINITE) speculated_value =   VALUE_INFINITE;
+
+        IterationInfo[Iteration].set(value, speculated_value, fHigh, fLow);

 
         // Erase the easy move if it differs from the new best move
         if (ss[0].pv[0] != EasyMove)
 
         // Erase the easy move if it differs from the new best move
         if (ss[0].pv[0] != EasyMove)


@@ -681,13 +799,13 @@ namespace {
 
             // Stop search early when the last two iterations returned a mate score
             if (  Iteration >= 6
 
             // Stop search early when the last two iterations returned a mate score
             if (  Iteration >= 6

-                && abs(ValueByIteration[Iteration]) >= abs(VALUE_MATE) - 100
-                && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100)
+                && abs(IterationInfo[Iteration].value()) >= abs(VALUE_MATE) - 100
+                && abs(IterationInfo[Iteration-1].value()) >= abs(VALUE_MATE) - 100)

                 stopSearch = true;
 
             // Stop search early if one move seems to be much better than the rest
             int64_t nodes = nodes_searched();
                 stopSearch = true;
 
             // Stop search early if one move seems to be much better than the rest
             int64_t nodes = nodes_searched();

-            if (   Iteration >= 8
+            if (   Iteration >= 8 && !fLow && !fHigh

                 && EasyMove == ss[0].pv[0]
                 && (  (   rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100
                        && current_search_time() > MaxSearchTime / 16)
                 && EasyMove == ss[0].pv[0]
                 && (  (   rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100
                        && current_search_time() > MaxSearchTime / 16)


@@ -700,9 +818,6 @@ namespace {
                 ExtraSearchTime = BestMoveChangesByIteration[Iteration]   * (MaxSearchTime / 2)
                                 + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3);
 
                 ExtraSearchTime = BestMoveChangesByIteration[Iteration]   * (MaxSearchTime / 2)
                                 + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3);
 

-            // Try to guess if the current iteration is the last one or the last two
-            LastIterations = (current_search_time() > ((MaxSearchTime + ExtraSearchTime)*58) / 128);
-

             // Stop search if most of MaxSearchTime is consumed at the end of the
             // iteration.  We probably don't have enough time to search the first
             // move at the next iteration anyway.
             // Stop search if most of MaxSearchTime is consumed at the end of the
             // iteration.  We probably don't have enough time to search the first
             // move at the next iteration anyway.


@@ -711,15 +826,13 @@ namespace {
 
             if (stopSearch)
             {
 
             if (stopSearch)
             {

+                //FIXME: Implement fail-low emergency measures

                 if (!PonderSearch)
                     break;
                 else
                     StopOnPonderhit = true;
             }
         }
                 if (!PonderSearch)
                     break;
                 else
                     StopOnPonderhit = true;
             }
         }

-        // Write PV to transposition table, in case the relevant entries have
-        // been overwritten during the search:
-        TT.insert_pv(p, ss[0].pv);

 
         if (MaxDepth && Iteration >= MaxDepth)
             break;
 
         if (MaxDepth && Iteration >= MaxDepth)
             break;


@@ -739,6 +852,11 @@ namespace {
                   << " hashfull " << TT.full() << std::endl;
 
     // Print the best move and the ponder move to the standard output
                   << " hashfull " << TT.full() << std::endl;
 
     // Print the best move and the ponder move to the standard output

+    if (ss[0].pv[0] == MOVE_NONE)
+    {
+        ss[0].pv[0] = rml.get_move(0);
+        ss[0].pv[1] = MOVE_NONE;
+    }

     std::cout << "bestmove " << ss[0].pv[0];
     if (ss[0].pv[1] != MOVE_NONE)
         std::cout << " ponder " << ss[0].pv[1];
     std::cout << "bestmove " << ss[0].pv[0];
     if (ss[0].pv[1] != MOVE_NONE)
         std::cout << " ponder " << ss[0].pv[1];


@@ -771,14 +889,22 @@ namespace {
   // scheme (perhaps we should try to use this at internal PV nodes, too?)
   // and prints some information to the standard output.
 
   // scheme (perhaps we should try to use this at internal PV nodes, too?)
   // and prints some information to the standard output.
 

-  Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml) {
+  Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml, Value alpha, Value beta) {

 
 

-    Value alpha = -VALUE_INFINITE;
-    Value beta = VALUE_INFINITE, value;
+    Value bestValue = -VALUE_INFINITE;
+    Value oldAlpha = alpha;
+    Value value;
+    Bitboard dcCandidates = pos.discovered_check_candidates(pos.side_to_move());

 
     // Loop through all the moves in the root move list
     for (int i = 0; i <  rml.move_count() && !AbortSearch; i++)
     {
 
     // Loop through all the moves in the root move list
     for (int i = 0; i <  rml.move_count() && !AbortSearch; i++)
     {

+        if (alpha >= beta) { //Aspiration window failed high, ignore rest of the moves!
+          rml.set_move_score(i, -VALUE_INFINITE);
+          //Leave node-counters and beta-counters as they are.
+          continue;
+        }
+

         int64_t nodes;
         Move move;
         StateInfo st;
         int64_t nodes;
         Move move;
         StateInfo st;


@@ -807,16 +933,16 @@ namespace {
         newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
 
         // Make the move, and search it
         newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
 
         // Make the move, and search it

-        pos.do_move(move, st);
+        pos.do_move(move, st, dcCandidates);

 
         if (i < MultiPV)
         {
 
         if (i < MultiPV)
         {

-            value = -search_pv(pos, ss, -beta, VALUE_INFINITE, newDepth, 1, 0);
+            value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);

             // If the value has dropped a lot compared to the last iteration,
             // set the boolean variable Problem to true. This variable is used
             // for time managment: When Problem is true, we try to complete the
             // current iteration before playing a move.
             // If the value has dropped a lot compared to the last iteration,
             // set the boolean variable Problem to true. This variable is used
             // for time managment: When Problem is true, we try to complete the
             // current iteration before playing a move.

-            Problem = (Iteration >= 2 && value <= ValueByIteration[Iteration-1] - ProblemMargin);
+            Problem = (Iteration >= 2 && value <= IterationInfo[Iteration-1].value() - ProblemMargin);

 
             if (Problem && StopOnPonderhit)
                 StopOnPonderhit = false;
 
             if (Problem && StopOnPonderhit)
                 StopOnPonderhit = false;


@@ -856,7 +982,7 @@ namespace {
 
         assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
 
 
         assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
 

-        if (value <= alpha && i >= MultiPV)
+        if (value <= bestValue && i >= MultiPV)

             rml.set_move_score(i, -VALUE_INFINITE);
         else
         {
             rml.set_move_score(i, -VALUE_INFINITE);
         else
         {


@@ -892,11 +1018,16 @@ namespace {
                     LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, ss[0].pv)
                             << std::endl;
 
                     LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, ss[0].pv)
                             << std::endl;
 

-                alpha = value;
+                if (value > bestValue)
+                {
+                  bestValue = value;
+                  if (value > alpha)
+                    alpha = value;
+                }

 
                 // Reset the global variable Problem to false if the value isn't too
                 // far below the final value from the last iteration.
 
                 // Reset the global variable Problem to false if the value isn't too
                 // far below the final value from the last iteration.

-                if (value > ValueByIteration[Iteration - 1] - NoProblemMargin)
+                if (value > IterationInfo[Iteration - 1].value() - NoProblemMargin)

                     Problem = false;
             }
             else // MultiPV > 1
                     Problem = false;
             }
             else // MultiPV > 1


@@ -919,10 +1050,17 @@ namespace {
                     std::cout << std::endl;
                 }
                 alpha = rml.get_move_score(Min(i, MultiPV-1));
                     std::cout << std::endl;
                 }
                 alpha = rml.get_move_score(Min(i, MultiPV-1));

+                bestValue = alpha; //In MultiPV-mode bestValue and alpha are always same thing.

             }
         }
             }
         }

+
+        if (bestValue <= oldAlpha)
+          FailLow = true;
+        else
+          FailLow = false;
+

     }
     }

-    return alpha;
+    return bestValue;

   }
 
 
   }
 
 


@@ -941,7 +1079,7 @@ namespace {
 
     // Initialize, and make an early exit in case of an aborted search,
     // an instant draw, maximum ply reached, etc.
 
     // Initialize, and make an early exit in case of an aborted search,
     // an instant draw, maximum ply reached, etc.

-    init_node(pos, ss, ply, threadID);
+    init_node(ss, ply, threadID);

 
     // After init_node() that calls poll()
     if (AbortSearch || thread_should_stop(threadID))
 
     // After init_node() that calls poll()
     if (AbortSearch || thread_should_stop(threadID))


@@ -981,6 +1119,7 @@ namespace {
     Move move, movesSearched[256];
     int moveCount = 0;
     Value value, bestValue = -VALUE_INFINITE;
     Move move, movesSearched[256];
     int moveCount = 0;
     Value value, bestValue = -VALUE_INFINITE;

+    Bitboard dcCandidates = mp.discovered_check_candidates();

     Color us = pos.side_to_move();
     bool isCheck = pos.is_check();
     bool mateThreat = pos.has_mate_threat(opposite_color(us));
     Color us = pos.side_to_move();
     bool isCheck = pos.is_check();
     bool mateThreat = pos.has_mate_threat(opposite_color(us));


@@ -994,17 +1133,11 @@ namespace {
       assert(move_is_ok(move));
 
       bool singleReply = (isCheck && mp.number_of_moves() == 1);
       assert(move_is_ok(move));
 
       bool singleReply = (isCheck && mp.number_of_moves() == 1);

-      bool moveIsCheck = pos.move_is_check(move);
+      bool moveIsCheck = pos.move_is_check(move, dcCandidates);

       bool moveIsCapture = pos.move_is_capture(move);
 
       movesSearched[moveCount++] = ss[ply].currentMove = move;
 
       bool moveIsCapture = pos.move_is_capture(move);
 
       movesSearched[moveCount++] = ss[ply].currentMove = move;
 

-      if (moveIsCapture)
-          ss[ply].currentMoveCaptureValue =
-          move_is_ep(move)? PawnValueMidgame : pos.midgame_value_of_piece_on(move_to(move));
-      else
-          ss[ply].currentMoveCaptureValue = Value(0);
-

       // Decide the new search depth
       bool dangerous;
       Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous);
       // Decide the new search depth
       bool dangerous;
       Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous);


@@ -1012,7 +1145,7 @@ namespace {
 
       // Make and search the move
       StateInfo st;
 
       // Make and search the move
       StateInfo st;

-      pos.do_move(move, st);
+      pos.do_move(move, st, dcCandidates);

 
       if (moveCount == 1) // The first move in list is the PV
           value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID);
 
       if (moveCount == 1) // The first move in list is the PV
           value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID);


@@ -1074,7 +1207,7 @@ namespace {
           // (from the computer's point of view) since the previous iteration:
           if (   ply == 1
               && Iteration >= 2
           // (from the computer's point of view) since the previous iteration:
           if (   ply == 1
               && Iteration >= 2

-              && -value <= ValueByIteration[Iteration-1] - ProblemMargin)
+              && -value <= IterationInfo[Iteration-1].value() - ProblemMargin)

               Problem = true;
       }
 
               Problem = true;
       }
 


@@ -1087,7 +1220,7 @@ namespace {
           && !AbortSearch
           && !thread_should_stop(threadID)
           && split(pos, ss, ply, &alpha, &beta, &bestValue, depth,
           && !AbortSearch
           && !thread_should_stop(threadID)
           && split(pos, ss, ply, &alpha, &beta, &bestValue, depth,

-                   &moveCount, &mp, threadID, true))
+                   &moveCount, &mp, dcCandidates, threadID, true))

           break;
     }
 
           break;
     }
 


@@ -1136,7 +1269,7 @@ namespace {
 
     // Initialize, and make an early exit in case of an aborted search,
     // an instant draw, maximum ply reached, etc.
 
     // Initialize, and make an early exit in case of an aborted search,
     // an instant draw, maximum ply reached, etc.

-    init_node(pos, ss, ply, threadID);
+    init_node(ss, ply, threadID);

 
     // After init_node() that calls poll()
     if (AbortSearch || thread_should_stop(threadID))
 
     // After init_node() that calls poll()
     if (AbortSearch || thread_should_stop(threadID))


@@ -1169,7 +1302,6 @@ namespace {
 
     Value approximateEval = quick_evaluate(pos);
     bool mateThreat = false;
 
     Value approximateEval = quick_evaluate(pos);
     bool mateThreat = false;

-    bool nullDrivenIID = false;

     bool isCheck = pos.is_check();
 
     // Null move search
     bool isCheck = pos.is_check();
 
     // Null move search


@@ -1184,23 +1316,10 @@ namespace {
 
         StateInfo st;
         pos.do_null_move(st);
 
         StateInfo st;
         pos.do_null_move(st);

-        int R = (depth >= 4 * OnePly ? 4 : 3); // Null move dynamic reduction
+        int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction

 
         Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
 
 
         Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
 

-        // Check for a null capture artifact, if the value without the null capture
-        // is above beta then mark the node as a suspicious failed low. We will verify
-        // later if we are really under threat.
-        if (   UseNullDrivenIID
-            && nullValue < beta
-            && depth > 6 * OnePly
-            &&!value_is_mate(nullValue)
-            && ttMove == MOVE_NONE
-            && ss[ply + 1].currentMove != MOVE_NONE
-            && pos.move_is_capture(ss[ply + 1].currentMove)
-            && pos.see(ss[ply + 1].currentMove) + nullValue >= beta)
-            nullDrivenIID = true;
-

         pos.undo_null_move();
 
         if (value_is_mate(nullValue))
         pos.undo_null_move();
 
         if (value_is_mate(nullValue))


@@ -1224,10 +1343,8 @@ namespace {
             // low score (which will cause the reduced move to fail high in the
             // parent node, which will trigger a re-search with full depth).
             if (nullValue == value_mated_in(ply + 2))
             // low score (which will cause the reduced move to fail high in the
             // parent node, which will trigger a re-search with full depth).
             if (nullValue == value_mated_in(ply + 2))

-            {

                 mateThreat = true;
                 mateThreat = true;

-                nullDrivenIID = false;
-            }
+

             ss[ply].threatMove = ss[ply + 1].currentMove;
             if (   depth < ThreatDepth
                 && ss[ply - 1].reduction
             ss[ply].threatMove = ss[ply + 1].currentMove;
             if (   depth < ThreatDepth
                 && ss[ply - 1].reduction


@@ -1245,8 +1362,8 @@ namespace {
     {
         Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
         if (   (v < beta - RazorMargin - RazorMargin / 4)
     {
         Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
         if (   (v < beta - RazorMargin - RazorMargin / 4)

-            || (depth < 3*OnePly && v < beta - RazorMargin)
-            || (depth < 2*OnePly && v < beta - RazorMargin / 2))
+            || (depth <= 2*OnePly && v < beta - RazorMargin)
+            || (depth <=   OnePly && v < beta - RazorMargin / 2))

             return v;
     }
 
             return v;
     }
 


@@ -1257,22 +1374,6 @@ namespace {
         search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID);
         ttMove = ss[ply].pv[ply];
     }
         search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID);
         ttMove = ss[ply].pv[ply];
     }

-    else if (nullDrivenIID)
-    {
-        // The null move failed low due to a suspicious capture. Perhaps we
-        // are facing a null capture artifact due to the side to move change
-        // and this position should fail high. So do a normal search with a
-        // reduced depth to get a good ttMove to use in the following full
-        // depth search.
-        Move tm = ss[ply].threatMove;
-
-        assert(tm != MOVE_NONE);
-        assert(ttMove == MOVE_NONE);
-
-        search(pos, ss, beta, depth/2, ply, false, threadID);
-        ttMove = ss[ply].pv[ply];
-        ss[ply].threatMove = tm;
-    }

 
     // Initialize a MovePicker object for the current position, and prepare
     // to search all moves:
 
     // Initialize a MovePicker object for the current position, and prepare
     // to search all moves:


@@ -1281,6 +1382,7 @@ namespace {
     Move move, movesSearched[256];
     int moveCount = 0;
     Value value, bestValue = -VALUE_INFINITE;
     Move move, movesSearched[256];
     int moveCount = 0;
     Value value, bestValue = -VALUE_INFINITE;

+    Bitboard dcCandidates = mp.discovered_check_candidates();

     Value futilityValue = VALUE_NONE;
     bool useFutilityPruning =   UseFutilityPruning
                              && depth < SelectiveDepth
     Value futilityValue = VALUE_NONE;
     bool useFutilityPruning =   UseFutilityPruning
                              && depth < SelectiveDepth


@@ -1295,7 +1397,7 @@ namespace {
       assert(move_is_ok(move));
 
       bool singleReply = (isCheck && mp.number_of_moves() == 1);
       assert(move_is_ok(move));
 
       bool singleReply = (isCheck && mp.number_of_moves() == 1);

-      bool moveIsCheck = pos.move_is_check(move);
+      bool moveIsCheck = pos.move_is_check(move, dcCandidates);

       bool moveIsCapture = pos.move_is_capture(move);
 
       movesSearched[moveCount++] = ss[ply].currentMove = move;
       bool moveIsCapture = pos.move_is_capture(move);
 
       movesSearched[moveCount++] = ss[ply].currentMove = move;


@@ -1335,7 +1437,7 @@ namespace {
 
       // Make and search the move
       StateInfo st;
 
       // Make and search the move
       StateInfo st;

-      pos.do_move(move, st);
+      pos.do_move(move, st, dcCandidates);

 
       // Try to reduce non-pv search depth by one ply if move seems not problematic,
       // if the move fails high will be re-searched at full depth.
 
       // Try to reduce non-pv search depth by one ply if move seems not problematic,
       // if the move fails high will be re-searched at full depth.


@@ -1382,7 +1484,7 @@ namespace {
           && !AbortSearch
           && !thread_should_stop(threadID)
           && split(pos, ss, ply, &beta, &beta, &bestValue, depth, &moveCount,
           && !AbortSearch
           && !thread_should_stop(threadID)
           && split(pos, ss, ply, &beta, &beta, &bestValue, depth, &moveCount,

-                   &mp, threadID, false))
+                   &mp, dcCandidates, threadID, false))

         break;
     }
 
         break;
     }
 


@@ -1409,6 +1511,9 @@ namespace {
         }
         TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER);
     }
         }
         TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER);
     }

+
+    assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
+

     return bestValue;
   }
 
     return bestValue;
   }
 


@@ -1428,7 +1533,7 @@ namespace {
 
     // Initialize, and make an early exit in case of an aborted search,
     // an instant draw, maximum ply reached, etc.
 
     // Initialize, and make an early exit in case of an aborted search,
     // an instant draw, maximum ply reached, etc.

-    init_node(pos, ss, ply, threadID);
+    init_node(ss, ply, threadID);

 
     // After init_node() that calls poll()
     if (AbortSearch || thread_should_stop(threadID))
 
     // After init_node() that calls poll()
     if (AbortSearch || thread_should_stop(threadID))


@@ -1437,15 +1542,39 @@ namespace {
     if (pos.is_draw())
         return VALUE_DRAW;
 
     if (pos.is_draw())
         return VALUE_DRAW;
 

-    // Transposition table lookup
-    const TTEntry* tte = TT.retrieve(pos);
-    if (tte && ok_to_use_TT(tte, depth, beta, ply))
-        return value_from_tt(tte->value(), ply);
+    // Transposition table lookup, only when not in PV
+    TTEntry* tte = NULL;
+    bool pvNode = (beta - alpha != 1);
+    if (!pvNode)
+    {
+        tte = TT.retrieve(pos);
+        if (tte && ok_to_use_TT(tte, depth, beta, ply))
+        {
+            assert(tte->type() != VALUE_TYPE_EVAL);
+
+            return value_from_tt(tte->value(), ply);
+        }
+    }

 
     // Evaluate the position statically
     EvalInfo ei;
 
     // Evaluate the position statically
     EvalInfo ei;

+    Value staticValue;

     bool isCheck = pos.is_check();
     bool isCheck = pos.is_check();

-    Value staticValue = (isCheck ? -VALUE_INFINITE : evaluate(pos, ei, threadID));
+    ei.futilityMargin = Value(0); // Manually initialize futilityMargin
+
+    if (isCheck)
+        staticValue = -VALUE_INFINITE;
+
+    else if (tte && tte->type() == VALUE_TYPE_EVAL)
+    {
+        // Use the cached evaluation score if possible
+        assert(tte->value() == evaluate(pos, ei, threadID));
+        assert(ei.futilityMargin == Value(0));
+
+        staticValue = tte->value();
+    }
+    else
+        staticValue = evaluate(pos, ei, threadID);

 
     if (ply == PLY_MAX - 1)
         return evaluate(pos, ei, threadID);
 
     if (ply == PLY_MAX - 1)
         return evaluate(pos, ei, threadID);


@@ -1455,7 +1584,13 @@ namespace {
     Value bestValue = staticValue;
 
     if (bestValue >= beta)
     Value bestValue = staticValue;
 
     if (bestValue >= beta)

+    {
+        // Store the score to avoid a future costly evaluation() call
+        if (!isCheck && !tte && ei.futilityMargin == 0)
+            TT.store(pos, value_to_tt(bestValue, ply), Depth(-127*OnePly), MOVE_NONE, VALUE_TYPE_EVAL);
+

         return bestValue;
         return bestValue;

+    }

 
     if (bestValue > alpha)
         alpha = bestValue;
 
     if (bestValue > alpha)
         alpha = bestValue;


@@ -1463,10 +1598,10 @@ namespace {
     // Initialize a MovePicker object for the current position, and prepare
     // to search the moves.  Because the depth is <= 0 here, only captures,
     // queen promotions and checks (only if depth == 0) will be generated.
     // Initialize a MovePicker object for the current position, and prepare
     // to search the moves.  Because the depth is <= 0 here, only captures,
     // queen promotions and checks (only if depth == 0) will be generated.

-    bool pvNode = (beta - alpha != 1);
-    MovePicker mp = MovePicker(pos, pvNode, MOVE_NONE, EmptySearchStack, depth, isCheck ? NULL : &ei);
+    MovePicker mp = MovePicker(pos, pvNode, MOVE_NONE, EmptySearchStack, depth);

     Move move;
     int moveCount = 0;
     Move move;
     int moveCount = 0;

+    Bitboard dcCandidates = mp.discovered_check_candidates();

     Color us = pos.side_to_move();
     bool enoughMaterial = pos.non_pawn_material(us) > RookValueMidgame;
 
     Color us = pos.side_to_move();
     bool enoughMaterial = pos.non_pawn_material(us) > RookValueMidgame;
 


@@ -1486,7 +1621,7 @@ namespace {
           && !isCheck
           && !pvNode
           && !move_promotion(move)
           && !isCheck
           && !pvNode
           && !move_promotion(move)

-          && !pos.move_is_check(move)
+          && !pos.move_is_check(move, dcCandidates)

           && !pos.move_is_passed_pawn_push(move))
       {
           Value futilityValue = staticValue
           && !pos.move_is_passed_pawn_push(move))
       {
           Value futilityValue = staticValue


@@ -1514,7 +1649,7 @@ namespace {
 
       // Make and search the move.
       StateInfo st;
 
       // Make and search the move.
       StateInfo st;

-      pos.do_move(move, st);
+      pos.do_move(move, st, dcCandidates);

       Value value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
       pos.undo_move(move);
 
       Value value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
       pos.undo_move(move);
 


@@ -1540,7 +1675,14 @@ namespace {
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
 
     // Update transposition table
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
 
     // Update transposition table

-    TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_EXACT);
+    if (!pvNode)
+    {
+        Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
+        if (bestValue < beta)
+            TT.store(pos, value_to_tt(bestValue, ply), d, MOVE_NONE, VALUE_TYPE_UPPER);
+        else
+            TT.store(pos, value_to_tt(bestValue, ply), d, MOVE_NONE, VALUE_TYPE_LOWER);
+    }

 
     // Update killers only for good check moves
     Move m = ss[ply].currentMove;
 
     // Update killers only for good check moves
     Move m = ss[ply].currentMove;


@@ -1581,7 +1723,7 @@ namespace {
     {
       assert(move_is_ok(move));
 
     {
       assert(move_is_ok(move));
 

-      bool moveIsCheck = pos.move_is_check(move);
+      bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);

       bool moveIsCapture = pos.move_is_capture(move);
 
       lock_grab(&(sp->lock));
       bool moveIsCapture = pos.move_is_capture(move);
 
       lock_grab(&(sp->lock));


@@ -1606,7 +1748,7 @@ namespace {
 
       // Make and search the move.
       StateInfo st;
 
       // Make and search the move.
       StateInfo st;

-      pos.do_move(move, st);
+      pos.do_move(move, st, sp->dcCandidates);

 
       // Try to reduce non-pv search depth by one ply if move seems not problematic,
       // if the move fails high will be re-searched at full depth.
 
       // Try to reduce non-pv search depth by one ply if move seems not problematic,
       // if the move fails high will be re-searched at full depth.


@@ -1691,17 +1833,11 @@ namespace {
            && !thread_should_stop(threadID)
            && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
     {
            && !thread_should_stop(threadID)
            && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
     {

-      bool moveIsCheck = pos.move_is_check(move);
+      bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);

       bool moveIsCapture = pos.move_is_capture(move);
 
       assert(move_is_ok(move));
 
       bool moveIsCapture = pos.move_is_capture(move);
 
       assert(move_is_ok(move));
 

-      if (moveIsCapture)
-          ss[sp->ply].currentMoveCaptureValue =
-          move_is_ep(move)? PawnValueMidgame : pos.midgame_value_of_piece_on(move_to(move));
-      else
-          ss[sp->ply].currentMoveCaptureValue = Value(0);
-

       lock_grab(&(sp->lock));
       int moveCount = ++sp->moves;
       lock_release(&(sp->lock));
       lock_grab(&(sp->lock));
       int moveCount = ++sp->moves;
       lock_release(&(sp->lock));


@@ -1715,7 +1851,7 @@ namespace {
 
       // Make and search the move.
       StateInfo st;
 
       // Make and search the move.
       StateInfo st;

-      pos.do_move(move, st);
+      pos.do_move(move, st, sp->dcCandidates);

 
       // Try to reduce non-pv search depth by one ply if move seems not problematic,
       // if the move fails high will be re-searched at full depth.
 
       // Try to reduce non-pv search depth by one ply if move seems not problematic,
       // if the move fails high will be re-searched at full depth.


@@ -1784,7 +1920,7 @@ namespace {
         // (from the computer's point of view) since the previous iteration.
         if (   sp->ply == 1
             && Iteration >= 2
         // (from the computer's point of view) since the previous iteration.
         if (   sp->ply == 1
             && Iteration >= 2

-            && -value <= ValueByIteration[Iteration-1] - ProblemMargin)
+            && -value <= IterationInfo[Iteration-1].value() - ProblemMargin)

             Problem = true;
       }
       lock_release(&(sp->lock));
             Problem = true;
       }
       lock_release(&(sp->lock));


@@ -1986,41 +2122,13 @@ namespace {
   }
 
 
   }
 
 

-  // init_search_stack() initializes a search stack at the beginning of a
-  // new search from the root.
-  void init_search_stack(SearchStack& ss) {
-
-    ss.pv[0] = MOVE_NONE;
-    ss.pv[1] = MOVE_NONE;
-    ss.currentMove = MOVE_NONE;
-    ss.threatMove = MOVE_NONE;
-    ss.reduction = Depth(0);
-    for (int j = 0; j < KILLER_MAX; j++)
-        ss.killers[j] = MOVE_NONE;
-  }
-
-  void init_search_stack(SearchStack ss[]) {
-
-    for (int i = 0; i < 3; i++)
-    {
-        ss[i].pv[i] = MOVE_NONE;
-        ss[i].pv[i+1] = MOVE_NONE;
-        ss[i].currentMove = MOVE_NONE;
-        ss[i].threatMove = MOVE_NONE;
-        ss[i].reduction = Depth(0);
-        for (int j = 0; j < KILLER_MAX; j++)
-            ss[i].killers[j] = MOVE_NONE;
-    }
-  }
-
-

   // init_node() is called at the beginning of all the search functions
   // (search(), search_pv(), qsearch(), and so on) and initializes the search
   // stack object corresponding to the current node.  Once every
   // NodesBetweenPolls nodes, init_node() also calls poll(), which polls
   // for user input and checks whether it is time to stop the search.
 
   // init_node() is called at the beginning of all the search functions
   // (search(), search_pv(), qsearch(), and so on) and initializes the search
   // stack object corresponding to the current node.  Once every
   // NodesBetweenPolls nodes, init_node() also calls poll(), which polls
   // for user input and checks whether it is time to stop the search.
 

-  void init_node(const Position &pos, SearchStack ss[], int ply, int threadID) {
+  void init_node(SearchStack ss[], int ply, int threadID) {

     assert(ply >= 0 && ply < PLY_MAX);
     assert(threadID >= 0 && threadID < ActiveThreads);
 
     assert(ply >= 0 && ply < PLY_MAX);
     assert(threadID >= 0 && threadID < ActiveThreads);
 


@@ -2033,13 +2141,9 @@ namespace {
         NodesSincePoll = 0;
       }
     }
         NodesSincePoll = 0;
       }
     }

-    ss[ply].pv[ply] = ss[ply].pv[ply+1] = ss[ply].currentMove = MOVE_NONE;
-    ss[ply+2].mateKiller = MOVE_NONE;
-    ss[ply].threatMove = MOVE_NONE;
-    ss[ply].reduction = Depth(0);
-    ss[ply].currentMoveCaptureValue = Value(0);
-    for (int j = 0; j < KILLER_MAX; j++)
-        ss[ply+2].killers[j] = MOVE_NONE;
+
+    ss[ply].init(ply);
+    ss[ply+2].initKillers();

 
     if(Threads[threadID].printCurrentLine)
       print_current_line(ss, ply, threadID);
 
     if(Threads[threadID].printCurrentLine)
       print_current_line(ss, ply, threadID);


@@ -2445,11 +2549,11 @@ namespace {
         return;
 
     bool overTime =     t > AbsoluteMaxSearchTime
         return;
 
     bool overTime =     t > AbsoluteMaxSearchTime

-                     || (RootMoveNumber == 1 && t > MaxSearchTime + ExtraSearchTime)
-                     || (  !FailHigh && !fail_high_ply_1() && !Problem
+                     || (RootMoveNumber == 1 && t > MaxSearchTime + ExtraSearchTime && !FailLow) //FIXME: BUG??
+                     || (  !FailHigh && !FailLow && !fail_high_ply_1() && !Problem

                          && t > 6*(MaxSearchTime + ExtraSearchTime));
 
                          && t > 6*(MaxSearchTime + ExtraSearchTime));
 

-    if (   (Iteration >= 2 && (!InfiniteSearch && overTime))
+    if (   (Iteration >= 3 && (!InfiniteSearch && overTime))

         || (ExactMaxTime && t >= ExactMaxTime)
         || (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes))
         AbortSearch = true;
         || (ExactMaxTime && t >= ExactMaxTime)
         || (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes))
         AbortSearch = true;


@@ -2463,12 +2567,12 @@ namespace {
   void ponderhit() {
     int t = current_search_time();
     PonderSearch = false;
   void ponderhit() {
     int t = current_search_time();
     PonderSearch = false;

-    if(Iteration >= 2 &&
+    if(Iteration >= 3 &&

        (!InfiniteSearch && (StopOnPonderhit ||
                             t > AbsoluteMaxSearchTime ||
                             (RootMoveNumber == 1 &&
        (!InfiniteSearch && (StopOnPonderhit ||
                             t > AbsoluteMaxSearchTime ||
                             (RootMoveNumber == 1 &&

-                             t > MaxSearchTime + ExtraSearchTime) ||
-                            (!FailHigh && !fail_high_ply_1() && !Problem &&
+                             t > MaxSearchTime + ExtraSearchTime && !FailLow) ||
+                            (!FailHigh && !FailLow && !fail_high_ply_1() && !Problem &&

                              t > 6*(MaxSearchTime + ExtraSearchTime)))))
       AbortSearch = true;
   }
                              t > 6*(MaxSearchTime + ExtraSearchTime)))))
       AbortSearch = true;
   }


@@ -2671,8 +2775,9 @@ namespace {
   // splitPoint->cpus becomes 0), split() returns true.
 
   bool split(const Position &p, SearchStack *sstck, int ply,
   // splitPoint->cpus becomes 0), split() returns true.
 
   bool split(const Position &p, SearchStack *sstck, int ply,

-             Value *alpha, Value *beta, Value *bestValue,
-             Depth depth, int *moves, MovePicker *mp, int master, bool pvNode) {
+             Value *alpha, Value *beta, Value *bestValue, Depth depth, int *moves,
+             MovePicker *mp, Bitboard dcCandidates, int master, bool pvNode) {
+

     assert(p.is_ok());
     assert(sstck != NULL);
     assert(ply >= 0 && ply < PLY_MAX);
     assert(p.is_ok());
     assert(sstck != NULL);
     assert(ply >= 0 && ply < PLY_MAX);


@@ -2708,6 +2813,7 @@ namespace {
     splitPoint->alpha = pvNode? *alpha : (*beta - 1);
     splitPoint->beta = *beta;
     splitPoint->pvNode = pvNode;
     splitPoint->alpha = pvNode? *alpha : (*beta - 1);
     splitPoint->beta = *beta;
     splitPoint->pvNode = pvNode;

+    splitPoint->dcCandidates = dcCandidates;

     splitPoint->bestValue = *bestValue;
     splitPoint->master = master;
     splitPoint->mp = mp;
     splitPoint->bestValue = *bestValue;
     splitPoint->master = master;
     splitPoint->mp = mp;