X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=29b7c5f3ebab93a78b832a23905a0e07af535800;hp=20beb23a11c44e0f75bcd99a08c506d7373e1658;hb=098ac5e44e88e95ad4ff945824315eca85e67f01;hpb=b5178597bd71c210de9e4245e26153c24fbb2c13

diff --git a/src/search.cpp b/src/search.cpp
index 20beb23a..29b7c5f3 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -90,7 +90,7 @@ namespace {
 
     template <bool Fake>
     void split(const Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
-               Depth depth, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode);
+               Depth depth, Move threatMove, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode);
 
   private:
     friend void poll();
@@ -309,6 +309,8 @@ namespace {
   void wait_for_stop_or_ponderhit();
   void init_ss_array(SearchStack* ss, int size);
   void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value);
+  void insert_pv_in_tt(const Position& pos, Move pv[]);
+  void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]);
 
 #if !defined(_MSC_VER)
   void *init_thread(void *threadID);
@@ -358,20 +360,6 @@ void init_search() {
 }
 
 
-// SearchStack::init() initializes a search stack entry.
-// Called at the beginning of search() when starting to examine a new node.
-void SearchStack::init() {
-
-  currentMove = threatMove = bestMove = MOVE_NONE;
-}
-
-// SearchStack::initKillers() initializes killers for a search stack entry
-void SearchStack::initKillers() {
-
-  killers[0] = killers[1] = mateKiller = MOVE_NONE;
-}
-
-
 /// perft() is our utility to verify move generation is bug free. All the legal
 /// moves up to given depth are generated and counted and the sum returned.
 
@@ -628,7 +616,7 @@ namespace {
 
         // Write PV to transposition table, in case the relevant entries have
         // been overwritten during the search.
-        TT.insert_pv(p, pv);
+        insert_pv_in_tt(p, pv);
 
         if (AbortSearch)
             break; // Value cannot be trusted. Break out immediately!
@@ -761,7 +749,7 @@ namespace {
     isCheck = pos.is_check();
 
     // Step 1. Initialize node (polling is omitted at root)
-    ss->init();
+    ss->currentMove = ss->bestMove = MOVE_NONE;
 
     // Step 2. Check for aborted search (omitted at root)
     // Step 3. Mate distance pruning (omitted at root)
@@ -895,7 +883,7 @@ namespace {
                 // the score before research in case we run out of time while researching.
                 rml.set_move_score(i, value);
                 ss->bestMove = move;
-                TT.extract_pv(pos, move, pv, PLY_MAX);
+                extract_pv_from_tt(pos, move, pv);
                 rml.set_move_pv(i, pv);
 
                 // Print information to the standard output
@@ -935,7 +923,7 @@ namespace {
                 // Update PV
                 rml.set_move_score(i, value);
                 ss->bestMove = move;
-                TT.extract_pv(pos, move, pv, PLY_MAX);
+                extract_pv_from_tt(pos, move, pv);
                 rml.set_move_pv(i, pv);
 
                 if (MultiPV == 1)
@@ -1016,7 +1004,7 @@ namespace {
     StateInfo st;
     const TTEntry* tte;
     Key posKey;
-    Move ttMove, move, excludedMove;
+    Move ttMove, move, excludedMove, threatMove;
     Depth ext, newDepth;
     Value bestValue, value, oldAlpha;
     Value refinedValue, nullValue, futilityValueScaled; // Non-PV specific
@@ -1029,8 +1017,8 @@ namespace {
 
     // Step 1. Initialize node and poll. Polling can abort search
     TM.incrementNodeCounter(threadID);
-    ss->init();
-    (ss+2)->initKillers();
+    ss->currentMove = ss->bestMove = threatMove = MOVE_NONE;
+    (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE;
 
     if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
     {
@@ -1083,13 +1071,17 @@ namespace {
     isCheck = pos.is_check();
     if (!isCheck)
     {
-        if (tte && tte->static_value() != VALUE_NONE)
+        if (tte)
         {
+            assert(tte->static_value() != VALUE_NONE);
             ss->eval = tte->static_value();
             ei.kingDanger[pos.side_to_move()] = tte->king_danger();
         }
         else
+        {
             ss->eval = evaluate(pos, ei);
+            TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+        }
 
         refinedValue = refine_eval(tte, ss->eval, ply); // Enhance accuracy with TT value if possible
         update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
@@ -1107,10 +1099,6 @@ namespace {
         && !value_is_mate(beta)
         && !pos.has_pawn_on_7th(pos.side_to_move()))
     {
-        // Pass ss->eval to qsearch() and avoid an evaluate call
-        if (!tte || tte->static_value() == VALUE_NONE)
-            TT.store(posKey, ss->eval, VALUE_TYPE_EXACT, Depth(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
-
         Value rbeta = beta - razor_margin(depth);
         Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, Depth(0), ply);
         if (v < rbeta)
@@ -1188,10 +1176,10 @@ namespace {
             if (nullValue == value_mated_in(ply + 2))
                 mateThreat = true;
 
-            ss->threatMove = (ss+1)->currentMove;
+            threatMove = (ss+1)->currentMove;
             if (   depth < ThreatDepth
                 && (ss-1)->reduction
-                && connected_moves(pos, (ss-1)->currentMove, ss->threatMove))
+                && connected_moves(pos, (ss-1)->currentMove, threatMove))
                 return beta - 1;
         }
     }
@@ -1280,7 +1268,7 @@ namespace {
       {
           // Move count based pruning
           if (   moveCount >= futility_move_count(depth)
-              && !(ss->threatMove && connected_threat(pos, move, ss->threatMove))
+              && !(threatMove && connected_threat(pos, move, threatMove))
               && bestValue > value_mated_in(PLY_MAX))
               continue;
 
@@ -1388,7 +1376,7 @@ namespace {
           && !TM.thread_should_stop(threadID)
           && Iteration <= 99)
           TM.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
-                              mateThreat, &moveCount, &mp, PvNode);
+                              threatMove, mateThreat, &moveCount, &mp, PvNode);
     }
 
     // Step 19. Check for mate and stalemate
@@ -1476,8 +1464,9 @@ namespace {
     }
     else
     {
-        if (tte && tte->static_value() != VALUE_NONE)
+        if (tte)
         {
+            assert(tte->static_value() != VALUE_NONE);
             ei.kingDanger[pos.side_to_move()] = tte->king_danger();
             bestValue = tte->static_value();
         }
@@ -1491,7 +1480,7 @@ namespace {
         if (bestValue >= beta)
         {
             if (!tte)
-                TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, Depth(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+                TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
 
             return bestValue;
         }
@@ -1661,7 +1650,7 @@ namespace {
       {
           // Move count based pruning
           if (   moveCount >= futility_move_count(sp->depth)
-              && !(ss->threatMove && connected_threat(pos, move, ss->threatMove))
+              && !(sp->threatMove && connected_threat(pos, move, sp->threatMove))
               && sp->bestValue > value_mated_in(PLY_MAX))
           {
               lock_grab(&(sp->lock));
@@ -2210,7 +2199,7 @@ namespace {
         ss->reduction = Depth(0);
 
         if (i < 3)
-            ss->initKillers();
+            ss->killers[0] = ss->killers[1] = ss->mateKiller = MOVE_NONE;
     }
   }
 
@@ -2271,6 +2260,61 @@ namespace {
   }
 
 
+  // insert_pv_in_tt() is called at the end of a search iteration, and inserts
+  // the PV back into the TT. This makes sure the old PV moves are searched
+  // first, even if the old TT entries have been overwritten.
+
+  void insert_pv_in_tt(const Position& pos, Move pv[]) {
+
+    StateInfo st;
+    TTEntry* tte;
+    Position p(pos, pos.thread());
+    EvalInfo ei;
+    Value v;
+
+    for (int i = 0; pv[i] != MOVE_NONE; i++)
+    {
+        tte = TT.retrieve(p.get_key());
+        if (!tte || tte->move() != pv[i])
+        {
+            v = (p.is_check() ? VALUE_NONE : evaluate(p, ei));
+            TT.store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[i], v, ei.kingDanger[pos.side_to_move()]);
+        }
+        p.do_move(pv[i], st);
+    }
+  }
+
+
+  // extract_pv_from_tt() builds a PV by adding moves from the transposition table.
+  // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This
+  // allow to always have a ponder move even when we fail high at root and also a
+  // long PV to print that is important for position analysis.
+
+  void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]) {
+
+    StateInfo st;
+    TTEntry* tte;
+    Position p(pos, pos.thread());
+    int ply = 0;
+
+    assert(bestMove != MOVE_NONE);
+
+    pv[ply] = bestMove;
+    p.do_move(pv[ply++], st);
+
+    while (   (tte = TT.retrieve(p.get_key())) != NULL
+           && tte->move() != MOVE_NONE
+           && move_is_legal(p, tte->move())
+           && ply < PLY_MAX
+           && (!p.is_draw() || ply < 2))
+    {
+        pv[ply] = tte->move();
+        p.do_move(pv[ply++], st);
+    }
+    pv[ply] = MOVE_NONE;
+  }
+
+
   // init_thread() is the function which is called when a new thread is
   // launched. It simply calls the idle_loop() function with the supplied
   // threadID. There are two versions of this function; one for POSIX
@@ -2426,8 +2470,8 @@ namespace {
 #endif
 
     // Initialize global locks
-    lock_init(&MPLock, NULL);
-    lock_init(&WaitLock, NULL);
+    lock_init(&MPLock);
+    lock_init(&WaitLock);
 
 #if !defined(_MSC_VER)
     pthread_cond_init(&WaitCond, NULL);
@@ -2439,7 +2483,7 @@ namespace {
     // Initialize splitPoints[] locks
     for (i = 0; i < MAX_THREADS; i++)
         for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
-            lock_init(&(threads[i].splitPoints[j].lock), NULL);
+            lock_init(&(threads[i].splitPoints[j].lock));
 
     // Will be set just before program exits to properly end the threads
     AllThreadsShouldExit = false;
@@ -2582,8 +2626,8 @@ namespace {
 
   template <bool Fake>
   void ThreadsManager::split(const Position& p, SearchStack* ss, int ply, Value* alpha,
-                             const Value beta, Value* bestValue, Depth depth, bool mateThreat,
-                             int* moveCount, MovePicker* mp, bool pvNode) {
+                             const Value beta, Value* bestValue, Depth depth, Move threatMove,
+                             bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode) {
     assert(p.is_ok());
     assert(ply > 0 && ply < PLY_MAX);
     assert(*bestValue >= -VALUE_INFINITE);
@@ -2616,6 +2660,7 @@ namespace {
     splitPoint.stopRequest = false;
     splitPoint.ply = ply;
     splitPoint.depth = depth;
+    splitPoint.threatMove = threatMove;
     splitPoint.mateThreat = mateThreat;
     splitPoint.alpha = *alpha;
     splitPoint.beta = beta;
@@ -2732,7 +2777,7 @@ namespace {
 
     // Initialize search stack
     init_ss_array(ss, PLY_MAX_PLUS_2);
-    ss[0].init();
+    ss[0].currentMove = ss[0].bestMove = MOVE_NONE;
     ss[0].eval = VALUE_NONE;
 
     // Generate all legal moves