Mobility is zero for a pinned piece

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index a4ce7eff3abf10c7a76c057c75271a4f1a4949df..b00c270bbd94bd034dcfe96fcd2bd6d979c0ccbc 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -162,13 +162,14 @@ namespace {
   bool UseQSearchFutilityPruning = true;
   bool UseFutilityPruning = true;
 
-  // Margins for futility pruning in the quiescence search, at frontier
-  // nodes, and at pre-frontier nodes
-  Value FutilityMargin0 = Value(0x80);
-  Value FutilityMargin1 = Value(0x100);
-  Value FutilityMargin2 = Value(0x200);
+  // Margins for futility pruning in the quiescence search, and at frontier
+  // and near frontier nodes
+  Value FutilityMarginQS = Value(0x80);
+  Value FutilityMargins[6] = { Value(0x100), Value(0x200), Value(0x250),
+                               Value(0x2A0), Value(0x340), Value(0x3A0) };
 
   // Razoring
+  const bool RazorAtDepthOne = false;
   Depth RazorDepth = 4*OnePly;
   Value RazorMargin = Value(0x300);
 
@@ -266,7 +267,7 @@ namespace {
   bool connected_moves(const Position &pos, Move m1, Move m2);
   bool value_is_mate(Value value);
   bool move_is_killer(Move m, const SearchStack& ss);
-  Depth extension(const Position &pos, Move m, bool pvNode, bool check, bool singleReply, bool mateThreat, bool* dangerous);
+  Depth extension(const Position &pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
   bool ok_to_do_nullmove(const Position &pos);
   bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d);
   bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
@@ -415,9 +416,10 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
   UseQSearchFutilityPruning = get_option_value_bool("Futility Pruning (Quiescence Search)");
   UseFutilityPruning = get_option_value_bool("Futility Pruning (Main Search)");
 
-  FutilityMargin0 = value_from_centipawns(get_option_value_int("Futility Margin 0"));
-  FutilityMargin1 = value_from_centipawns(get_option_value_int("Futility Margin 1"));
-  FutilityMargin2 = value_from_centipawns(get_option_value_int("Futility Margin 2"));
+  FutilityMarginQS = value_from_centipawns(get_option_value_int("Futility Margin (Quiescence Search)"));
+  int fmScale = get_option_value_int("Futility Margin Scale Factor (Main Search)");
+  for (int i = 0; i < 6; i++)
+      FutilityMargins[i] = (FutilityMargins[i] * fmScale) / 100;
 
   RazorDepth = (get_option_value_int("Maximum Razoring Depth") + 1) * OnePly;
   RazorMargin = value_from_centipawns(get_option_value_int("Razoring Margin"));
@@ -447,7 +449,6 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
   // Set thinking time:
   int myTime = time[side_to_move];
   int myIncrement = increment[side_to_move];
-  int oppTime = time[1 - side_to_move];
 
   if (!movesToGo) // Sudden death time control
   {
@@ -804,7 +805,7 @@ namespace {
 
         // Decide search depth for this move
         bool dangerous;
-        ext = extension(pos, move, true, pos.move_is_check(move), false, false, &dangerous);
+        ext = extension(pos, move, true, pos.move_is_capture(move), pos.move_is_check(move), false, false, &dangerous);
         newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
 
         // Make the move, and search it
@@ -1008,7 +1009,7 @@ namespace {
 
       // Decide the new search depth
       bool dangerous;
-      Depth ext = extension(pos, move, true, moveIsCheck, singleReply, mateThreat, &dangerous);
+      Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous);
       Depth newDepth = depth - OnePly + ext;
 
       // Make and search the move
@@ -1239,10 +1240,15 @@ namespace {
     // Null move search not allowed, try razoring
     else if (   !value_is_mate(beta)
              && approximateEval < beta - RazorMargin
-             && depth < RazorDepth)
+             && depth < RazorDepth
+             && (RazorAtDepthOne || depth > OnePly)
+             && ttMove == MOVE_NONE
+             && !pos.has_pawn_on_7th(pos.side_to_move()))
     {
         Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
-        if (v < beta - RazorMargin / 2)
+        if (   (v < beta - RazorMargin - RazorMargin / 4)
+            || (depth < 3*OnePly && v < beta - RazorMargin)
+            || (depth < 2*OnePly && v < beta - RazorMargin / 2))
             return v;
     }
 
@@ -1299,7 +1305,7 @@ namespace {
 
       // Decide the new search depth
       bool dangerous;
-      Depth ext = extension(pos, move, false, moveIsCheck, singleReply, mateThreat, &dangerous);
+      Depth ext = extension(pos, move, false, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous);
       Depth newDepth = depth - OnePly + ext;
 
       // Futility pruning
@@ -1314,12 +1320,13 @@ namespace {
               continue;
 
           // Value based pruning
-          if (depth < 6 * OnePly && approximateEval < beta)
+          if (depth < 7 * OnePly && approximateEval < beta)
           {
               if (futilityValue == VALUE_NONE)
                   futilityValue =  evaluate(pos, ei, threadID)
-                                + (depth < 2 * OnePly ? FutilityMargin1
-                                                      : FutilityMargin2 + (depth - 2*OnePly) * 32);
+                                 + FutilityMargins[int(depth)/2 - 1]
+                                 + 32 * (depth & 1);
+
               if (futilityValue < beta)
               {
                   if (futilityValue > bestValue)
@@ -1489,7 +1496,7 @@ namespace {
                               + Max(pos.midgame_value_of_piece_on(move_to(move)),
                                     pos.endgame_value_of_piece_on(move_to(move)))
                               + (move_is_ep(move) ? PawnValueEndgame : Value(0))
-                              + FutilityMargin0
+                              + FutilityMarginQS
                               + ei.futilityMargin;
 
           if (futilityValue < alpha)
@@ -1588,7 +1595,7 @@ namespace {
 
       // Decide the new search depth.
       bool dangerous;
-      Depth ext = extension(pos, move, false, moveIsCheck, false, false, &dangerous);
+      Depth ext = extension(pos, move, false, moveIsCapture, moveIsCheck, false, false, &dangerous);
       Depth newDepth = sp->depth - OnePly + ext;
 
       // Prune?
@@ -1706,7 +1713,7 @@ namespace {
 
       // Decide the new search depth.
       bool dangerous;
-      Depth ext = extension(pos, move, true, moveIsCheck, false, false, &dangerous);
+      Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, false, false, &dangerous);
       Depth newDepth = sp->depth - OnePly + ext;
 
       // Make and search the move.
@@ -2171,7 +2178,7 @@ namespace {
   // extended, as example because the corresponding UCI option is set to zero,
   // the move is marked as 'dangerous' so, at least, we avoid to prune it.
 
-  Depth extension(const Position &pos, Move m, bool pvNode, bool check,
+  Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check,
                   bool singleReply, bool mateThreat, bool* dangerous) {
 
     assert(m != MOVE_NONE);
@@ -2188,18 +2195,21 @@ namespace {
     if (mateThreat)
         result += MateThreatExtension[pvNode];
 
-    if (pos.move_is_pawn_push_to_7th(m))
+    if (pos.type_of_piece_on(move_from(m)) == PAWN)
     {
-        result += PawnPushTo7thExtension[pvNode];
-        *dangerous = true;
-    }
-    if (pos.move_is_passed_pawn_push(m))
-    {
-        result += PassedPawnExtension[pvNode];
-        *dangerous = true;
+        if (pos.move_is_pawn_push_to_7th(m))
+        {
+            result += PawnPushTo7thExtension[pvNode];
+            *dangerous = true;
+        }
+        if (pos.move_is_passed_pawn_push(m))
+        {
+            result += PassedPawnExtension[pvNode];
+            *dangerous = true;
+        }
     }
 
-    if (   pos.move_is_capture(m)
+    if (   capture
         && pos.type_of_piece_on(move_to(m)) != PAWN
         && (  pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
             - pos.midgame_value_of_piece_on(move_to(m)) == Value(0))
@@ -2211,7 +2221,7 @@ namespace {
     }
 
     if (   pvNode
-        && pos.move_is_capture(m)
+        && capture
         && pos.type_of_piece_on(move_to(m)) != PAWN
         && pos.see(m) >= 0)
     {