Sync with master

bench: 7374604

src/evaluate.cpp

@@ -91,7 +91,7 @@ namespace {
   // Evaluation weights, indexed by evaluation term
   enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety };
   const struct Weight { int mg, eg; } Weights[] = {
-    {289, 344}, {233, 201}, {221, 273}, {46, 0}, {321, 0}
+    {289, 344}, {233, 201}, {221, 273}, {46, 0}, {324, 0}
   };
 
   #define V(v) Value(v)
@@ -186,15 +186,15 @@ namespace {
   // index to KingDanger[].
   //
   // KingAttackWeights[PieceType] contains king attack weights by piece type
-  const int KingAttackWeights[] = { 0, 0, 6, 2, 5, 5 };
+  const int KingAttackWeights[] = { 0, 0, 8, 4, 4, 1 };
 
   // Bonuses for enemy's safe checks
-  const int QueenContactCheck = 92;
+  const int QueenContactCheck = 89;
-  const int RookContactCheck  = 68;
+  const int RookContactCheck  = 72;
-  const int QueenCheck        = 50;
+  const int QueenCheck        = 51;
-  const int RookCheck         = 36;
+  const int RookCheck         = 38;
-  const int BishopCheck       = 7;
+  const int BishopCheck       = 5;
-  const int KnightCheck       = 14;
+  const int KnightCheck       = 16;
 
   // KingDanger[attackUnits] contains the actual king danger weighted
   // scores, indexed by a calculated integer number.
@@ -411,11 +411,11 @@ namespace {
         // number and types of the enemy's attacking pieces, the number of
         // attacked and undefended squares around our king and the quality of
         // the pawn shelter (current 'score' value).
-        attackUnits =  std::min(77, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
+        attackUnits =  std::min(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
-                     + 10 * ei.kingAdjacentZoneAttacksCount[Them]
+                     + 9 * ei.kingAdjacentZoneAttacksCount[Them]
-                     + 19 * popcount<Max15>(undefended)
+                     + 25 * popcount<Max15>(undefended)
-                     +  9 * (ei.pinnedPieces[Us] != 0)
+                     +  10 * (ei.pinnedPieces[Us] != 0)
-                     - mg_value(score) * 63 / 512
+                     - mg_value(score) / 8
                      - !pos.count<QUEEN>(Them) * 60;
 
         // Analyse the enemy's safe queen contact checks. Firstly, find the
@@ -891,13 +891,13 @@ namespace Eval {
 
   void init() {
 
-    const double MaxSlope = 7.5;
+    const double MaxSlope = 8.5;
     const double Peak = 1280;
     double t = 0.0;
 
     for (int i = 1; i < 400; ++i)
     {
-        t = std::min(Peak, std::min(0.025 * i * i, t + MaxSlope));
+        t = std::min(Peak, std::min(0.027 * i * i, t + MaxSlope));
         KingDanger[i] = apply_weight(make_score(int(t), 0), Weights[KingSafety]);
     }
   }

src/pawns.cpp

@@ -63,33 +63,33 @@ namespace {
 
   // Weakness of our pawn shelter in front of the king by [distance from edge][rank]
   const Value ShelterWeakness[][RANK_NB] = {
-  { V(100), V(13), V(24), V(64), V(89), V( 93), V(104) },
+  { V( 99), V(23), V(24), V(54), V(85), V( 93), V(107) },
-  { V(110), V( 1), V(29), V(75), V(96), V(102), V(107) },
+  { V(119), V( 2), V(28), V(72), V(96), V(104), V(114) },
-  { V(102), V( 0), V(39), V(74), V(88), V(101), V( 98) },
+  { V(103), V( 6), V(47), V(74), V(84), V(103), V( 94) },
-  { V( 88), V( 4), V(33), V(67), V(92), V( 94), V(107) } };
+  { V( 78), V(10), V(41), V(64), V(88), V( 92), V(115) } };
 
   // Danger of enemy pawns moving toward our king by [type][distance from edge][rank]
   const Value StormDanger[][4][RANK_NB] = {
-  { { V( 0),  V(  63), V( 128), V(43), V(27) },
+  { { V( 0),  V(  65), V( 125), V(37), V(30) },
-    { V( 0),  V(  62), V( 131), V(44), V(26) },
+    { V( 0),  V(  57), V( 136), V(39), V(24) },
-    { V( 0),  V(  59), V( 121), V(50), V(28) },
+    { V( 0),  V(  50), V( 114), V(45), V(29) },
-    { V( 0),  V(  62), V( 127), V(54), V(28) } },
+    { V( 0),  V(  58), V( 129), V(56), V(34) } },
-  { { V(24),  V(  40), V(  93), V(42), V(22) },
+  { { V(20),  V(  45), V(  91), V(47), V(20) },
-    { V(24),  V(  28), V( 101), V(38), V(20) },
+    { V(25),  V(  23), V( 105), V(38), V(14) },
-    { V(24),  V(  32), V(  95), V(36), V(23) },
+    { V(21),  V(  37), V(  99), V(35), V(21) },
-    { V(27),  V(  24), V(  99), V(36), V(24) } },
+    { V(30),  V(  18), V( 105), V(38), V(28) } },
-  { { V( 0),  V(   0), V(  81), V(16), V( 6) },
+  { { V( 0),  V(   0), V(  81), V(13), V( 4) },
-    { V( 0),  V(   0), V( 165), V(29), V( 9) },
+    { V( 0),  V(   0), V( 169), V(30), V( 4) },
-    { V( 0),  V(   0), V( 163), V(23), V(12) },
+    { V( 0),  V(   0), V( 166), V(24), V( 6) },
-    { V( 0),  V(   0), V( 161), V(28), V(13) } },
+    { V( 0),  V(   0), V( 164), V(24), V(11) } },
-  { { V( 0),  V(-296), V(-299), V(55), V(25) },
+  { { V( 0),  V(-289), V(-297), V(57), V(29) },
-    { V( 0),  V(  67), V( 131), V(46), V(21) },
+    { V( 0),  V(  66), V( 136), V(43), V(16) },
-    { V( 0),  V(  65), V( 135), V(50), V(31) },
+    { V( 0),  V(  66), V( 141), V(50), V(31) },
-    { V( 0),  V(  62), V( 128), V(51), V(24) } } };
+    { V( 0),  V(  63), V( 126), V(52), V(23) } } };
 
   // Max bonus for king safety. Corresponds to start position with all the pawns
   // in front of the king and no enemy pawn on the horizon.
-  const Value MaxSafetyBonus = V(257);
+  const Value MaxSafetyBonus = V(252);
 
   #undef S
   #undef V
@@ -144,12 +144,11 @@ namespace {
         lever       =   theirPawns & pawnAttacksBB[s];
 
         // Test for backward pawn.
-        // If the pawn is passed, isolated, or connected it cannot be
+        // If the pawn is passed, isolated, connected or a lever it cannot be
         // backward. If there are friendly pawns behind on adjacent files
-        // or if it can capture an enemy pawn it cannot be backward either.
+        // it cannot be backward either.
-        if (   (passed | isolated | connected)
+        if (   (passed | isolated | connected | lever)
-            || (ourPawns & pawn_attack_span(Them, s))
+            || (ourPawns & pawn_attack_span(Them, s)))
-            || (pos.attacks_from<PAWN>(s, Us) & theirPawns))
             backward = false;
         else
         {

src/search.cpp

@@ -268,7 +268,7 @@ 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;
@@ -360,7 +360,8 @@ 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;
 
@@ -829,7 +830,8 @@ 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)
@@ -1389,10 +1391,6 @@ moves_loop: // When in check and at SpNode search starts from here
     {
         int score = RootMoves[i].score;
 
-        // Don't allow crazy blunders even at very low skills
-        if (i > 0 && RootMoves[i - 1].score > score + 2 * PawnValueMg)
-            break;
-
         // This is our magic formula
         score += (  weakness * int(RootMoves[0].score - score)
                   + variance * (rng.rand<unsigned>() % weakness)) / 128;
@@ -1488,6 +1486,30 @@ 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() {

src/search.h

@@ -60,6 +60,7 @@ struct RootMove {
   bool operator<(const RootMove& m) const { return score > m.score; } // Ascending sort
   bool operator==(const Move& m) const { return pv[0] == m; }
   void insert_pv_in_tt(Position& pos);
+  Move extract_ponder_from_tt(Position& pos);
 
   Value score;
   Value previousScore;