Simplify aspiration window

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 1c000b5bad78a8d847d5f4d8c3ecfe130dff2e48..6e5d6ab3dae5e8b04d7db201c513b6ff74aecfa3 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -383,6 +383,9 @@ void Thread::search() {
       // MultiPV loop. We perform a full root search for each PV line
       for (PVIdx = 0; PVIdx < multiPV && !Threads.stop; ++PVIdx)
       {
+          // Reset UCI info selDepth for each depth and each PV line
+          selDepth = 0;
+
           // Reset aspiration window starting size
           if (rootDepth >= 5 * ONE_PLY)
           {
@@ -434,10 +437,7 @@ void Thread::search() {
                   }
               }
               else if (bestValue >= beta)
-              {
-                  alpha = (alpha + beta) / 2;
                   beta = std::min(bestValue + delta, VALUE_INFINITE);
-              }
               else
                   break;
 
@@ -566,8 +566,8 @@ namespace {
         static_cast<MainThread*>(thisThread)->check_time();
 
     // Used to send selDepth info to GUI
-    if (PvNode && thisThread->maxPly < ss->ply)
-        thisThread->maxPly = ss->ply;
+    if (PvNode && thisThread->selDepth < ss->ply)
+        thisThread->selDepth = ss->ply;
 
     if (!rootNode)
     {
@@ -1043,6 +1043,7 @@ moves_loop: // When in check search starts from here
           if (moveCount == 1 || value > alpha)
           {
               rm.score = value;
+              rm.selDepth = thisThread->selDepth;
               rm.pv.resize(1);
 
               assert((ss+1)->pv);
@@ -1057,8 +1058,8 @@ moves_loop: // When in check search starts from here
                   ++static_cast<MainThread*>(thisThread)->bestMoveChanges;
           }
           else
-              // All other moves but the PV are set to the lowest value: this is
-              // not a problem when sorting because the sort is stable and the
+              // All other moves but the PV are set to the lowest value: this
+              // is not a problem when sorting because the sort is stable and the
               // move position in the list is preserved - just the PV is pushed up.
               rm.score = -VALUE_INFINITE;
       }
@@ -1525,7 +1526,7 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) {
 
       ss << "info"
          << " depth "    << d / ONE_PLY
-         << " seldepth " << pos.this_thread()->maxPly
+         << " seldepth " << rootMoves[i].selDepth
          << " multipv "  << i + 1
          << " score "    << UCI::value(v);