X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=25383aae9d2504801f05e8e82aff4245d3990f61;hp=ad54a7265417d12e4ea7994b4ea3baf34855af43;hb=108f0da4d7f993732aa2e854b8f3fa8ca6d3b46c;hpb=e9aeaad05266ca557a9496b5a17b4c5f82f0e946

diff --git a/src/search.cpp b/src/search.cpp
index ad54a726..25383aae 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -48,7 +48,6 @@ namespace Tablebases {
   bool RootInTB;
   bool UseRule50;
   Depth ProbeDepth;
-  Value Score;
 }
 
 namespace TB = Tablebases;
@@ -354,9 +353,20 @@ void Thread::search() {
       for (RootMove& rm : rootMoves)
           rm.previousScore = rm.score;
 
+      size_t PVFirst = 0;
+      PVLast = 0;
+
       // MultiPV loop. We perform a full root search for each PV line
       for (PVIdx = 0; PVIdx < multiPV && !Threads.stop; ++PVIdx)
       {
+          if (PVIdx == PVLast)
+          {
+              PVFirst = PVLast;
+              for (PVLast++; PVLast < rootMoves.size(); PVLast++)
+                  if (rootMoves[PVLast].TBRank != rootMoves[PVFirst].TBRank)
+                      break;
+          }
+
           // Reset UCI info selDepth for each depth and each PV line
           selDepth = 0;
 
@@ -388,7 +398,7 @@ void Thread::search() {
               // and we want to keep the same order for all the moves except the
               // new PV that goes to the front. Note that in case of MultiPV
               // search the already searched PV lines are preserved.
-              std::stable_sort(rootMoves.begin() + PVIdx, rootMoves.end());
+              std::stable_sort(rootMoves.begin() + PVIdx, rootMoves.begin() + PVLast);
 
               // If search has been stopped, we break immediately. Sorting is
               // safe because RootMoves is still valid, although it refers to
@@ -428,7 +438,7 @@ void Thread::search() {
           }
 
           // Sort the PV lines searched so far and update the GUI
-          std::stable_sort(rootMoves.begin(), rootMoves.begin() + PVIdx + 1);
+          std::stable_sort(rootMoves.begin() + PVFirst, rootMoves.begin() + PVIdx + 1);
 
           if (    mainThread
               && (Threads.stop || PVIdx + 1 == multiPV || Time.elapsed() > 3000))
@@ -843,9 +853,10 @@ moves_loop: // When in check, search starts from here
 
       // At root obey the "searchmoves" option and skip moves not listed in Root
       // Move List. As a consequence any illegal move is also skipped. In MultiPV
-      // mode we also skip PV moves which have been already searched.
+      // mode we also skip PV moves which have been already searched and those
+      // of lower "TB rank" if we are in a TB root position.
       if (rootNode && !std::count(thisThread->rootMoves.begin() + thisThread->PVIdx,
-                                  thisThread->rootMoves.end(), move))
+                                  thisThread->rootMoves.begin() + thisThread->PVLast, move))
           continue;
 
       ss->moveCount = ++moveCount;
@@ -1557,7 +1568,7 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) {
       Value v = updated ? rootMoves[i].score : rootMoves[i].previousScore;
 
       bool tb = TB::RootInTB && abs(v) < VALUE_MATE - MAX_PLY;
-      v = tb ? TB::Score : v;
+      v = tb ? rootMoves[i].TBScore : v;
 
       if (ss.rdbuf()->in_avail()) // Not at first line
           ss << "\n";
@@ -1618,52 +1629,49 @@ bool RootMove::extract_ponder_from_tt(Position& pos) {
     return pv.size() > 1;
 }
 
-
-void Tablebases::filter_root_moves(Position& pos, Search::RootMoves& rootMoves) {
+void Tablebases::rank_root_moves(Position& pos, Search::RootMoves& rootMoves) {
 
     RootInTB = false;
     UseRule50 = Options["Syzygy50MoveRule"];
     ProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY;
     Cardinality = Options["SyzygyProbeLimit"];
+    bool dtz_available = true;
 
-    // Skip TB probing when no TB found: !TBLargest -> !TB::Cardinality
+    // Tables with fewer pieces than SyzygyProbeLimit are searched with
+    // ProbeDepth == DEPTH_ZERO
     if (Cardinality > MaxCardinality)
     {
         Cardinality = MaxCardinality;
         ProbeDepth = DEPTH_ZERO;
     }
 
-    if (Cardinality < popcount(pos.pieces()) || pos.can_castle(ANY_CASTLING))
-        return;
-
-    // Don't filter any moves if the user requested analysis on multiple
-    if (Options["MultiPV"] != 1)
-        return;
+    if (Cardinality >= popcount(pos.pieces()) && !pos.can_castle(ANY_CASTLING))
+    {
+        // Rank moves using DTZ tables
+        RootInTB = root_probe(pos, rootMoves);
 
-    // 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)
+        {
+            // DTZ tables are missing; try to rank moves using WDL tables
+            dtz_available = false;
+            RootInTB = root_probe_wdl(pos, rootMoves);
+        }
+    }
 
     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);
+        // Sort moves according to TB rank
+        std::sort(rootMoves.begin(), rootMoves.end(),
+                  [](const RootMove &a, const RootMove &b) { return a.TBRank > b.TBRank; } );
 
-        // Only probe during search if winning
-        if (RootInTB && TB::Score <= VALUE_DRAW)
+        // Probe during search only if DTZ is not available and we are winning
+        if (dtz_available || rootMoves[0].TBScore <= VALUE_DRAW)
             Cardinality = 0;
     }
-
-    if (RootInTB && !UseRule50)
-        TB::Score =  TB::Score > VALUE_DRAW ?  VALUE_MATE - MAX_PLY - 1
-                   : TB::Score < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1
-                                            :  VALUE_DRAW;
-
-    // Since root_probe() and root_probe_wdl() dirty the root move scores,
-    // we reset them to -VALUE_INFINITE
-    for (RootMove& rm : rootMoves)
-        rm.score = -VALUE_INFINITE;
+    else
+    {
+        // Assign the same rank to all moves
+        for (auto& m : rootMoves)
+            m.TBRank = 0;
+    }
 }