LMR dynamic reduction

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 64acc3a89b640231155f13f0ccdaad796a19361d..295ef63ea24d1c9645b26aa694b5be0c353e7f8c 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -748,6 +748,11 @@ namespace {
                   << " hashfull " << TT.full() << std::endl;
 
     // Print the best move and the ponder move to the standard output
+    if (ss[0].pv[0] == MOVE_NONE)
+    {
+        ss[0].pv[0] = rml.get_move(0);
+        ss[0].pv[1] = MOVE_NONE;
+    }
     std::cout << "bestmove " << ss[0].pv[0];
     if (ss[0].pv[1] != MOVE_NONE)
         std::cout << " ponder " << ss[0].pv[1];
@@ -1327,8 +1332,11 @@ namespace {
           && !move_is_castle(move)
           && !move_is_killer(move, ss[ply]))
       {
-          ss[ply].reduction = OnePly;
-          value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID);
+          // LMR dynamic reduction
+          Depth R = (moveCount >= 3 * LMRNonPVMoves && depth >= 7*OnePly ? 2*OnePly : OnePly);
+
+          ss[ply].reduction = R;
+          value = -search(pos, ss, -(beta-1), newDepth-R, ply+1, true, threadID);
       }
       else
         value = beta; // Just to trigger next condition
@@ -1389,6 +1397,9 @@ namespace {
         }
         TT.store(pos, value_to_tt(bestValue, ply), depth, m, VALUE_TYPE_LOWER);
     }
+
+    assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
+
     return bestValue;
   }