]> git.sesse.net Git - stockfish/blobdiff - src/search.cpp
Remove useless condition in late join
[stockfish] / src / search.cpp
index 564653ef6672aed2ce6cc0125de2f4bc5e4a40ef..1062c9203a7bbc0c31c0b134e1d1f882d95f4a76 100644 (file)
@@ -173,7 +173,7 @@ uint64_t Search::perft(Position& pos, Depth depth) {
           cnt = 1, nodes++;
       else
       {
-          pos.do_move(*it, st, ci, pos.gives_check(*it, ci));
+          pos.do_move(*it, st, pos.gives_check(*it, ci));
           cnt = leaf ? MoveList<LEGAL>(pos).size() : perft<false>(pos, depth - ONE_PLY);
           nodes += cnt;
           pos.undo_move(*it);
@@ -276,7 +276,7 @@ void Search::think() {
 
   sync_cout << "bestmove " << UCI::move(RootMoves[0].pv[0], RootPos.is_chess960());
 
-  if (RootMoves[0].pv.size() > 1)
+  if (RootMoves[0].pv.size() > 1 || RootMoves[0].extract_ponder_from_tt(RootPos))
       std::cout << " ponder " << UCI::move(RootMoves[0].pv[1], RootPos.is_chess960());
 
   std::cout << sync_endl;
@@ -365,7 +365,8 @@ namespace {
 
                 // When failing high/low give some update (without cluttering
                 // the UI) before a re-search.
-                if (  (bestValue <= alpha || bestValue >= beta)
+                if (   multiPV == 1
+                    && (bestValue <= alpha || bestValue >= beta)
                     && Time::now() - SearchTime > 3000)
                     sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
 
@@ -701,7 +702,7 @@ namespace {
             if (pos.legal(move, ci.pinned))
             {
                 ss->currentMove = move;
-                pos.do_move(move, st, ci, pos.gives_check(move, ci));
+                pos.do_move(move, st, pos.gives_check(move, ci));
                 value = -search<NonPV, false>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode);
                 pos.undo_move(move);
                 if (value >= rbeta)
@@ -830,7 +831,8 @@ moves_loop: // When in check and at SpNode search starts from here
       newDepth = depth - ONE_PLY + extension;
 
       // Step 13. Pruning at shallow depth
-      if (   !captureOrPromotion
+      if (   !RootNode
+          && !captureOrPromotion
           && !inCheck
           && !dangerous
           &&  bestValue > VALUE_MATED_IN_MAX_PLY)
@@ -892,7 +894,7 @@ moves_loop: // When in check and at SpNode search starts from here
           quietsSearched[quietCount++] = move;
 
       // Step 14. Make the move
-      pos.do_move(move, st, ci, givesCheck);
+      pos.do_move(move, st, givesCheck);
 
       // Step 15. Reduced depth search (LMR). If the move fails high it will be
       // re-searched at full depth.
@@ -1040,7 +1042,9 @@ moves_loop: // When in check and at SpNode search starts from here
           &&  Threads.size() >= 2
           &&  depth >= Threads.minimumSplitDepth
           &&  (   !thisThread->activeSplitPoint
-               || !thisThread->activeSplitPoint->allSlavesSearching)
+               || !thisThread->activeSplitPoint->allSlavesSearching
+               || (   int(Threads.size()) > MAX_SLAVES_PER_SPLITPOINT
+                   && thisThread->activeSplitPoint->slavesCount == MAX_SLAVES_PER_SPLITPOINT))
           &&  thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD)
       {
           assert(bestValue > -VALUE_INFINITE && bestValue < beta);
@@ -1253,7 +1257,7 @@ moves_loop: // When in check and at SpNode search starts from here
       ss->currentMove = move;
 
       // Make and search the move
-      pos.do_move(move, st, ci, givesCheck);
+      pos.do_move(move, st, givesCheck);
       value = givesCheck ? -qsearch<NT,  true>(pos, ss+1, -beta, -alpha, depth - ONE_PLY)
                          : -qsearch<NT, false>(pos, ss+1, -beta, -alpha, depth - ONE_PLY);
       pos.undo_move(move);
@@ -1391,10 +1395,6 @@ moves_loop: // When in check and at SpNode search starts from here
     {
         int score = RootMoves[i].score;
 
-        // Don't allow crazy blunders even at very low skills
-        if (i > 0 && RootMoves[i - 1].score > score + 2 * PawnValueMg)
-            break;
-
         // This is our magic formula
         score += (  weakness * int(RootMoves[0].score - score)
                   + variance * (rng.rand<unsigned>() % weakness)) / 128;
@@ -1449,8 +1449,12 @@ moves_loop: // When in check and at SpNode search starts from here
               ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");
 
         ss << " nodes "     << pos.nodes_searched()
-           << " nps "       << pos.nodes_searched() * 1000 / elapsed
-           << " tbhits "    << TB::Hits
+           << " nps "       << pos.nodes_searched() * 1000 / elapsed;
+
+        if (elapsed > 1000) // Earlier makes little sense
+           ss << " hashfull "  << TT.hashfull();
+
+        ss << " tbhits "    << TB::Hits
            << " time "      << elapsed
            << " pv";
 
@@ -1490,6 +1494,30 @@ 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 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.
+
+Move RootMove::extract_ponder_from_tt(Position& pos)
+{
+    StateInfo st;
+    bool found;
+
+    assert(pv.size() == 1);
+
+    pos.do_move(pv[0], st);
+    TTEntry* tte = TT.probe(pos.key(), found);
+    Move m = found ? tte->move() : MOVE_NONE;
+    if (!MoveList<LEGAL>(pos).contains(m))
+        m = MOVE_NONE;
+
+    pos.undo_move(pv[0]);
+    pv.push_back(m);
+    return m;
+}
+
+
 /// Thread::idle_loop() is where the thread is parked when it has no work to do
 
 void Thread::idle_loop() {
@@ -1560,34 +1588,57 @@ void Thread::idle_loop() {
 
           // Try to late join to another split point if none of its slaves has
           // already finished.
-          if (Threads.size() > 2)
-              for (size_t i = 0; i < Threads.size(); ++i)
+          SplitPoint* bestSp = NULL;
+          int bestThread = 0;
+          int bestScore = INT_MAX;
+
+          for (size_t i = 0; i < Threads.size(); ++i)
+          {
+              const int size = Threads[i]->splitPointsSize; // Local copy
+              sp = size ? &Threads[i]->splitPoints[size - 1] : NULL;
+
+              if (   sp
+                  && sp->allSlavesSearching
+                  && sp->slavesCount < MAX_SLAVES_PER_SPLITPOINT
+                  && available_to(Threads[i]))
               {
-                  const int size = Threads[i]->splitPointsSize; // Local copy
-                  sp = size ? &Threads[i]->splitPoints[size - 1] : NULL;
+                  // Compute the recursive split points chain size
+                  int level = -1;
+                  for (SplitPoint* spp = Threads[i]->activeSplitPoint; spp; spp = spp->parentSplitPoint)
+                      level++;
+
+                  int score = level * 256 * 256 + sp->slavesCount * 256 - sp->depth * 1;
 
-                  if (   sp
-                      && sp->allSlavesSearching
-                      && available_to(Threads[i]))
+                  if (score < bestScore)
                   {
-                      // Recheck the conditions under lock protection
-                      Threads.mutex.lock();
-                      sp->mutex.lock();
-
-                      if (   sp->allSlavesSearching
-                          && available_to(Threads[i]))
-                      {
-                           sp->slavesMask.set(idx);
-                           activeSplitPoint = sp;
-                           searching = true;
-                      }
-
-                      sp->mutex.unlock();
-                      Threads.mutex.unlock();
-
-                      break; // Just a single attempt
+                      bestSp = sp;
+                      bestThread = i;
+                      bestScore = score;
                   }
               }
+          }
+
+          if (bestSp)
+          {
+              sp = bestSp;
+
+              // Recheck the conditions under lock protection
+              Threads.mutex.lock();
+              sp->mutex.lock();
+
+              if (   sp->allSlavesSearching
+                  && sp->slavesCount < MAX_SLAVES_PER_SPLITPOINT
+                  && available_to(Threads[bestThread]))
+              {
+                  sp->slavesMask.set(idx);
+                  sp->slavesCount++;
+                  activeSplitPoint = sp;
+                  searching = true;
+              }
+
+              sp->mutex.unlock();
+              Threads.mutex.unlock();
+          }
       }
 
       // Grab the lock to avoid races with Thread::notify_one()