X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fsearch.cpp;h=0ce836f777797ac0d4b785cad8a911261a8c064c;hb=9f0d5241bfcf454d4b21594b0af239bbe5990b84;hp=564653ef6672aed2ce6cc0125de2f4bc5e4a40ef;hpb=ab276357d7dea388a81ea75f9b7d89670cf4fcf0;p=stockfish

diff --git a/src/search.cpp b/src/search.cpp
index 564653ef..0ce836f7 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -276,7 +276,7 @@ void Search::think() {
 
   sync_cout << "bestmove " << UCI::move(RootMoves[0].pv[0], RootPos.is_chess960());
 
-  if (RootMoves[0].pv.size() > 1)
+  if (RootMoves[0].pv.size() > 1 || RootMoves[0].extract_ponder_from_tt(RootPos))
       std::cout << " ponder " << UCI::move(RootMoves[0].pv[1], RootPos.is_chess960());
 
   std::cout << sync_endl;
@@ -365,7 +365,8 @@ namespace {
 
                 // When failing high/low give some update (without cluttering
                 // the UI) before a re-search.
-                if (  (bestValue <= alpha || bestValue >= beta)
+                if (   multiPV == 1
+                    && (bestValue <= alpha || bestValue >= beta)
                     && Time::now() - SearchTime > 3000)
                     sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
 
@@ -830,7 +831,8 @@ moves_loop: // When in check and at SpNode search starts from here
       newDepth = depth - ONE_PLY + extension;
 
       // Step 13. Pruning at shallow depth
-      if (   !captureOrPromotion
+      if (   !RootNode
+          && !captureOrPromotion
           && !inCheck
           && !dangerous
           &&  bestValue > VALUE_MATED_IN_MAX_PLY)
@@ -1490,6 +1492,30 @@ void RootMove::insert_pv_in_tt(Position& pos) {
 }
 
 
+/// RootMove::extract_ponder_from_tt() is called in case we have no ponder move before
+/// exiting the search, for instance in case we stop the search during a fail high at
+/// root. We try hard to have a ponder move to return to the GUI, otherwise in case of
+/// 'ponder on' we have nothing to think on.
+
+Move RootMove::extract_ponder_from_tt(Position& pos)
+{
+    StateInfo st;
+    bool found;
+
+    assert(pv.size() == 1);
+
+    pos.do_move(pv[0], st);
+    TTEntry* tte = TT.probe(pos.key(), found);
+    Move m = found ? tte->move() : MOVE_NONE;
+    if (!MoveList<LEGAL>(pos).contains(m))
+        m = MOVE_NONE;
+
+    pos.undo_move(pv[0]);
+    pv.push_back(m);
+    return m;
+}
+
+
 /// Thread::idle_loop() is where the thread is parked when it has no work to do
 
 void Thread::idle_loop() {