Fix multiPV issue #502

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index db2d933d0eaf0172b086a08c7b26512168c47ca4..2c9240146b32b46791efcb755a46f3236a83f18c 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -68,7 +68,8 @@ namespace {
   const int skipPhase[] = { 0, 1, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 7 };
 
   // Razoring and futility margin based on depth
-  const int razor_margin[4] = { 483, 570, 603, 554 };
+  // razor_margin[0] is unused as long as depth >= ONE_PLY in search
+  const int razor_margin[] = { 0, 570, 603, 554 };
   Value futility_margin(Depth d) { return Value(150 * d / ONE_PLY); }
 
   // Futility and reductions lookup tables, initialized at startup
@@ -878,7 +879,7 @@ moves_loop: // When in check search starts from here
       // (alpha-s, beta-s), and just one fails high on (alpha, beta), then that move
       // is singular and should be extended. To verify this we do a reduced search
       // on all the other moves but the ttMove and if the result is lower than
-      // ttValue minus a margin then we extend the ttMove.
+      // ttValue minus a margin then we will extend the ttMove.
       if (    singularExtensionNode
           &&  move == ttMove
           &&  pos.legal(move))
@@ -1282,6 +1283,7 @@ moves_loop: // When in check search starts from here
 
       // Detect non-capture evasions that are candidates to be pruned
       evasionPrunable =    InCheck
+                       &&  depth != DEPTH_ZERO
                        &&  bestValue > VALUE_MATED_IN_MAX_PLY
                        && !pos.capture(move);
 
@@ -1503,7 +1505,7 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) {
 
   for (size_t i = 0; i < multiPV; ++i)
   {
-      bool updated = (i <= PVIdx);
+      bool updated = (i <= PVIdx && rootMoves[i].score != -VALUE_INFINITE);
 
       if (depth == ONE_PLY && !updated)
           continue;