Filter root moves filter before copy to threads
authorMarco Costalba <mcostalba@gmail.com>
Sat, 4 Jun 2016 05:53:29 +0000 (07:53 +0200)
committerMarco Costalba <mcostalba@gmail.com>
Sat, 11 Jun 2016 07:24:40 +0000 (09:24 +0200)
Currently root moves are copied to all teh threads
but are DTZ filtered only in main thread at the
beginning of teh search.

This patch moves the TB filtering before the
copy of root moves fixing issue #679

https://github.com/official-stockfish/Stockfish/issues/679

No bench change.

src/search.cpp
src/syzygy/tbprobe.h
src/thread.cpp
src/thread.h
src/uci.cpp

index a26a7bc..995204f 100644 (file)
@@ -261,19 +261,6 @@ void MainThread::search() {
   DrawValue[ us] = VALUE_DRAW - Value(contempt);
   DrawValue[~us] = VALUE_DRAW + Value(contempt);
 
-  TB::Hits = 0;
-  TB::RootInTB = false;
-  TB::UseRule50 = Options["Syzygy50MoveRule"];
-  TB::ProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY;
-  TB::Cardinality = Options["SyzygyProbeLimit"];
-
-  // Skip TB probing when no TB found: !TBLargest -> !TB::Cardinality
-  if (TB::Cardinality > TB::MaxCardinality)
-  {
-      TB::Cardinality = TB::MaxCardinality;
-      TB::ProbeDepth = DEPTH_ZERO;
-  }
-
   if (rootMoves.empty())
   {
       rootMoves.push_back(RootMove(MOVE_NONE));
@@ -283,38 +270,6 @@ void MainThread::search() {
   }
   else
   {
-      if (    TB::Cardinality >=  rootPos.count<ALL_PIECES>(WHITE)
-                                + rootPos.count<ALL_PIECES>(BLACK)
-          && !rootPos.can_castle(ANY_CASTLING))
-      {
-          // If the current root position is in the tablebases, then RootMoves
-          // contains only moves that preserve the draw or the win.
-          TB::RootInTB = Tablebases::root_probe(rootPos, rootMoves, TB::Score);
-
-          if (TB::RootInTB)
-              TB::Cardinality = 0; // Do not probe tablebases during the search
-
-          else // If DTZ tables are missing, use WDL tables as a fallback
-          {
-              // 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
-              if (TB::Score <= VALUE_DRAW)
-                  TB::Cardinality = 0;
-          }
-
-          if (TB::RootInTB)
-          {
-              TB::Hits = rootMoves.size();
-
-              if (!TB::UseRule50)
-                  TB::Score =  TB::Score > VALUE_DRAW ?  VALUE_MATE - MAX_PLY - 1
-                             : TB::Score < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1
-                                                      :  VALUE_DRAW;
-          }
-      }
-
       for (Thread* th : Threads)
           if (th != this)
               th->start_searching();
@@ -1661,3 +1616,49 @@ bool RootMove::extract_ponder_from_tt(Position& pos)
 
     return false;
 }
+
+void Tablebases::filter_root_moves(Position& pos, Search::RootMoves& rootMoves) {
+
+    Hits = 0;
+    RootInTB = false;
+    UseRule50 = Options["Syzygy50MoveRule"];
+    ProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY;
+    Cardinality = Options["SyzygyProbeLimit"];
+
+    // Skip TB probing when no TB found: !TBLargest -> !TB::Cardinality
+    if (Cardinality > MaxCardinality)
+    {
+        Cardinality = MaxCardinality;
+        ProbeDepth = DEPTH_ZERO;
+    }
+
+    if (Cardinality < popcount(pos.pieces()) || pos.can_castle(ANY_CASTLING))
+        return;
+
+    // If the current root position is in the tablebases, then RootMoves
+    // contains only moves that preserve the draw or the win.
+    RootInTB = root_probe(pos, rootMoves, TB::Score);
+
+    if (RootInTB)
+        Cardinality = 0; // Do not probe tablebases during the search
+
+    else // If DTZ tables are missing, use WDL tables as a fallback
+    {
+        // Filter out moves that do not preserve the draw or the win.
+        RootInTB = root_probe_wdl(pos, rootMoves, TB::Score);
+
+        // Only probe during search if winning
+        if (TB::Score <= VALUE_DRAW)
+            Cardinality = 0;
+    }
+
+    if (RootInTB)
+    {
+        Hits = rootMoves.size();
+
+        if (!UseRule50)
+            TB::Score =  TB::Score > VALUE_DRAW ?  VALUE_MATE - MAX_PLY - 1
+                       : TB::Score < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1
+                                                :  VALUE_DRAW;
+    }
+}
index 2bcc083..b23fdf6 100644 (file)
@@ -12,6 +12,7 @@ int probe_wdl(Position& pos, int *success);
 int probe_dtz(Position& pos, int *success);
 bool root_probe(Position& pos, Search::RootMoves& rootMoves, Value& score);
 bool root_probe_wdl(Position& pos, Search::RootMoves& rootMoves, Value& score);
+void filter_root_moves(Position& pos, Search::RootMoves& rootMoves);
 
 }
 
index 4dc7d9e..b38bdd6 100644 (file)
@@ -25,6 +25,7 @@
 #include "search.h"
 #include "thread.h"
 #include "uci.h"
+#include "syzygy/tbprobe.h"
 
 ThreadPool Threads; // Global object
 
@@ -169,7 +170,7 @@ int64_t ThreadPool::nodes_searched() {
 /// ThreadPool::start_thinking() wakes up the main thread sleeping in idle_loop()
 /// and starts a new search, then returns immediately.
 
-void ThreadPool::start_thinking(const Position& pos, StateListPtr& states,
+void ThreadPool::start_thinking(Position& pos, StateListPtr& states,
                                 const Search::LimitsType& limits) {
 
   main()->wait_for_search_finished();
@@ -183,6 +184,8 @@ void ThreadPool::start_thinking(const Position& pos, StateListPtr& states,
           || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
           rootMoves.push_back(Search::RootMove(m));
 
+  Tablebases::filter_root_moves(pos, rootMoves);
+
   // After ownership transfer 'states' becomes empty, so if we stop the search
   // and call 'go' again without setting a new position states.get() == NULL.
   assert(states.get() || setupStates.get());
index 0b112de..4e63fe4 100644 (file)
@@ -94,7 +94,7 @@ struct ThreadPool : public std::vector<Thread*> {
   void exit(); // be initialized and valid during the whole thread lifetime.
 
   MainThread* main() { return static_cast<MainThread*>(at(0)); }
-  void start_thinking(const Position&, StateListPtr&, const Search::LimitsType&);
+  void start_thinking(Position&, StateListPtr&, const Search::LimitsType&);
   void read_uci_options();
   int64_t nodes_searched();
 
index a9811a9..4ae6662 100644 (file)
@@ -108,7 +108,7 @@ namespace {
   // the thinking time and other parameters from the input string, then starts
   // the search.
 
-  void go(const Position& pos, istringstream& is) {
+  void go(Position& pos, istringstream& is) {
 
     Search::LimitsType limits;
     string token;