Retire Rml full PV search at depth == 1

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 4cce6a9171de9139d8e51e717d966af819912492..8088ff76c94ce36418d7307347ab16d211ae350e 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -534,8 +534,10 @@ namespace {
 
         Rml.bestMoveChanges = 0;
 
 
         Rml.bestMoveChanges = 0;
 

-        // MultiPV iteration loop
-        for (MultiPVIteration = 0; MultiPVIteration < Min(MultiPV, (int)Rml.size()); MultiPVIteration++)
+        // MultiPV iteration loop. At depth 1 perform at least 2 iterations to
+        // get a score of the second best move for easy move detection.
+        int e = Min(Max(MultiPV, 2 * int(depth == 1)), (int)Rml.size());
+        for (MultiPVIteration = 0; MultiPVIteration < e; MultiPVIteration++)

         {
             // Calculate dynamic aspiration window based on previous iterations
             if (depth >= 5 && abs(Rml[MultiPVIteration].prevScore) < VALUE_KNOWN_WIN)
         {
             // Calculate dynamic aspiration window based on previous iterations
             if (depth >= 5 && abs(Rml[MultiPVIteration].prevScore) < VALUE_KNOWN_WIN)


@@ -1000,8 +1002,7 @@ split_point_start: // At split points actual search starts from here
                    << " currmovenumber " << moveCount + MultiPVIteration << endl;
       }
 
                    << " currmovenumber " << moveCount + MultiPVIteration << endl;
       }
 

-      // At Root and at first iteration do a PV search on all the moves to score root moves
-      isPvMove = (PvNode && moveCount <= (RootNode && depth <= ONE_PLY ? MAX_MOVES : 1));
+      isPvMove = (PvNode && moveCount == 1);

       givesCheck = pos.move_gives_check(move, ci);
       captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       givesCheck = pos.move_gives_check(move, ci);
       captureOrPromotion = pos.move_is_capture_or_promotion(move);