Fix a comment and add an assert in root_search()

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 8539d66f41c6902ce7d226dbc6c0395f2a25f4a2..cef7fda3e813c4f02fbbcae0ea857e298186e6c5 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -84,7 +84,7 @@ namespace {
     void put_threads_to_sleep();
     void idle_loop(int threadID, SplitPoint* waitSp);
     bool split(const Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
-               Depth depth, int* moves, MovePicker* mp, int master, bool pvNode);
+               Depth depth, bool mateThreat, int* moves, MovePicker* mp, int master, bool pvNode);
 
   private:
     friend void poll(SearchStack ss[], int ply);
@@ -254,10 +254,10 @@ namespace {
   int MultiPV;
 
   // Time managment variables
-  int RootMoveNumber, SearchStartTime, MaxNodes, MaxDepth;
-  int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
+  int SearchStartTime, MaxNodes, MaxDepth, MaxSearchTime;
+  int AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
   bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
-  bool AbortSearch, Quit, AspirationFailLow;
+  bool FirstRootMove, AbortSearch, Quit, AspirationFailLow;
 
   // Show current line?
   bool ShowCurrentLine;
@@ -828,8 +828,8 @@ namespace {
         // Step 10. Loop through all moves in the root move list
         for (int i = 0; i <  rml.move_count() && !AbortSearch; i++)
         {
-            // This is used by time management and starts from 1
-            RootMoveNumber = i + 1;
+            // This is used by time management
+            FirstRootMove = (i == 0);
 
             // Save the current node count before the move is searched
             nodes = TM.nodes_searched();
@@ -843,7 +843,7 @@ namespace {
 
             if (current_search_time() >= 1000)
                 cout << "info currmove " << move
-                     << " currmovenumber " << RootMoveNumber << endl;
+                     << " currmovenumber " << i + 1 << endl;
 
             moveIsCheck = pos.move_is_check(move);
             captureOrPromotion = pos.move_is_capture_or_promotion(move);
@@ -950,6 +950,7 @@ namespace {
             rml.set_move_nodes(i, TM.nodes_searched() - nodes);
 
             assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
+            assert(value < beta);
 
             // Step 17. Check for new best move
             if (value <= alpha && i >= MultiPV)
@@ -975,8 +976,7 @@ namespace {
                     // Print information to the standard output
                     print_pv_info(pos, ss, alpha, beta, value);
 
-                    // Raise alpha to setup proper non-pv search upper bound, note
-                    // that we can end up with alpha >= beta and so get a fail high.
+                    // Raise alpha to setup proper non-pv search upper bound
                     if (value > alpha)
                         alpha = value;
                 }
@@ -1219,7 +1219,7 @@ namespace {
           && !AbortSearch
           && !TM.thread_should_stop(threadID)
           && TM.split(pos, ss, ply, &alpha, beta, &bestValue,
-                      depth, &moveCount, &mp, threadID, true))
+                      depth, mateThreat, &moveCount, &mp, threadID, true))
           break;
     }
 
@@ -1339,7 +1339,9 @@ namespace {
         Value rbeta = beta - razor_margin(depth);
         Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0), ply, threadID);
         if (v < rbeta)
-          return v; //FIXME: Logically should be: return (v + razor_margin(depth));
+            // Logically we should return (v + razor_margin(depth)), but
+            // surprisingly this did slightly weaker in tests.
+            return v;
     }
 
     // Step 7. Static null move pruning
@@ -1544,7 +1546,7 @@ namespace {
           && !AbortSearch
           && !TM.thread_should_stop(threadID)
           && TM.split(pos, ss, ply, NULL, beta, &bestValue,
-                      depth, &moveCount, &mp, threadID, false))
+                      depth, mateThreat, &moveCount, &mp, threadID, false))
           break;
     }
 
@@ -1780,7 +1782,6 @@ namespace {
   // splitting, we don't have to repeat all this work in sp_search().  We
   // also don't need to store anything to the hash table here:  This is taken
   // care of after we return from the split point.
-  // FIXME: We are currently ignoring mateThreat flag here
 
   void sp_search(SplitPoint* sp, int threadID) {
 
@@ -1817,7 +1818,7 @@ namespace {
       captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       // Step 11. Decide the new search depth
-      ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, false, false, &dangerous);
+      ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, false, sp->mateThreat, &dangerous);
       newDepth = sp->depth - OnePly + ext;
 
       // Update current move
@@ -1915,7 +1916,6 @@ namespace {
   // don't have to repeat all this work in sp_search_pv().  We also don't
   // need to store anything to the hash table here: This is taken care of
   // after we return from the split point.
-  // FIXME: We are ignoring mateThreat flag!
 
   void sp_search_pv(SplitPoint* sp, int threadID) {
 
@@ -1951,7 +1951,7 @@ namespace {
       captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       // Step 11. Decide the new search depth
-      ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
+      ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, sp->mateThreat, &dangerous);
       newDepth = sp->depth - OnePly + ext;
 
       // Update current move
@@ -2480,7 +2480,7 @@ namespace {
     if (PonderSearch)
         return;
 
-    bool stillAtFirstMove =    RootMoveNumber == 1
+    bool stillAtFirstMove =    FirstRootMove
                            && !AspirationFailLow
                            &&  t > MaxSearchTime + ExtraSearchTime;
 
@@ -2503,7 +2503,7 @@ namespace {
     int t = current_search_time();
     PonderSearch = false;
 
-    bool stillAtFirstMove =    RootMoveNumber == 1
+    bool stillAtFirstMove =    FirstRootMove
                            && !AspirationFailLow
                            &&  t > MaxSearchTime + ExtraSearchTime;
 
@@ -2892,7 +2892,7 @@ namespace {
 
   bool ThreadsManager::split(const Position& p, SearchStack* sstck, int ply,
              Value* alpha, const Value beta, Value* bestValue,
-             Depth depth, int* moves, MovePicker* mp, int master, bool pvNode) {
+             Depth depth, bool mateThreat, int* moves, MovePicker* mp, int master, bool pvNode) {
 
     assert(p.is_ok());
     assert(sstck != NULL);
@@ -2927,6 +2927,7 @@ namespace {
     splitPoint->stopRequest = false;
     splitPoint->ply = ply;
     splitPoint->depth = depth;
+    splitPoint->mateThreat = mateThreat;
     splitPoint->alpha = pvNode ? *alpha : beta - 1;
     splitPoint->beta = beta;
     splitPoint->pvNode = pvNode;