Filter root moves filter before copy to threads

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.

diff --git a/src/search.cpp b/src/search.cpp
index a26a7bc41c6dbf717231afcd9da6d06fd0656e2a..995204f34aab2bf4cca090eb3e66c41f1c857c8a 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -261,19 +261,6 @@ void MainThread::search() {
   DrawValue[ us] = VALUE_DRAW - Value(contempt);
   DrawValue[~us] = VALUE_DRAW + Value(contempt);
 
   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));
   if (rootMoves.empty())
   {
       rootMoves.push_back(RootMove(MOVE_NONE));


@@ -283,38 +270,6 @@ void MainThread::search() {
   }
   else
   {
   }
   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();
       for (Thread* th : Threads)
           if (th != this)
               th->start_searching();


@@ -1661,3 +1616,49 @@ bool RootMove::extract_ponder_from_tt(Position& pos)
 
     return false;
 }
 
     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;
+    }
+}

diff --git a/src/syzygy/tbprobe.h b/src/syzygy/tbprobe.h
index 2bcc0834c9cb8bb7896679703aa8627f067bba14..b23fdf66a1e5eb6c1aade5eacb59756da911a786 100644 (file)
--- a/src/syzygy/tbprobe.h
+++ b/src/syzygy/tbprobe.h
@@ -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);
 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);

 
 }
 
 
 }
 

diff --git a/src/thread.cpp b/src/thread.cpp
index 4dc7d9e9b02aa565a56dd626155c706baf5893ad..b38bdd6ed51e2848fd60770c936d7a80793e427c 100644 (file)
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -25,6 +25,7 @@
 #include "search.h"
 #include "thread.h"
 #include "uci.h"
 #include "search.h"
 #include "thread.h"
 #include "uci.h"

+#include "syzygy/tbprobe.h"

 
 ThreadPool Threads; // Global object
 
 
 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.
 
 /// 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();
                                 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));
 
           || 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());
   // 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());

diff --git a/src/thread.h b/src/thread.h
index 0b112de9b0f14540d414c506f61998053ad0c72e..4e63fe478073953fcffd7f474e728c8f659afd43 100644 (file)
--- a/src/thread.h
+++ b/src/thread.h
@@ -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 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();
 
   void read_uci_options();
   int64_t nodes_searched();
 

diff --git a/src/uci.cpp b/src/uci.cpp
index a9811a9af7352ae74308979a4751721b6bfcc042..4ae6662017768d5127dc44ea63c79d4dd25f22ff 100644 (file)
--- a/src/uci.cpp
+++ b/src/uci.cpp
@@ -108,7 +108,7 @@ namespace {
   // the thinking time and other parameters from the input string, then starts
   // the search.
 
   // 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;
 
     Search::LimitsType limits;
     string token;