X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=44c29ec878209a882c27f5880878443ac32a0081;hb=dd5a3ae4a6c7cc4adcbb4b72378694b0889139d7;hp=15609966438313776e47204d947c46e585a68b67;hpb=5e112f16daeec7f03a322cbd292bdbabf3246a48;p=stockfish

diff --git a/src/search.cpp b/src/search.cpp
index 15609966..44c29ec8 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -284,7 +284,7 @@ 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, Depth depth, bool pvNode, bool capture, 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);
@@ -334,7 +334,6 @@ int perft(Position& pos, Depth depth)
 {
     Move move;
     MovePicker mp = MovePicker(pos, MOVE_NONE, depth, H);
-    Bitboard dcCandidates = pos.discovered_check_candidates(pos.side_to_move());
     int sum = 0;
 
     // If we are at the last ply we don't need to do and undo
@@ -346,10 +345,11 @@ int perft(Position& pos, Depth depth)
     }
 
     // Loop through all legal moves
+    CheckInfo ci(pos);
     while ((move = mp.get_next_move()) != MOVE_NONE)
     {
       StateInfo st;
-      pos.do_move(move, st, dcCandidates);
+      pos.do_move(move, st, ci.dcCandidates, pos.move_is_check(move, ci));
       sum += perft(pos, depth - OnePly);
       pos.undo_move(move);
     }
@@ -862,7 +862,7 @@ namespace {
 
     Value oldAlpha = alpha;
     Value value;
-    Bitboard dcCandidates = pos.discovered_check_candidates(pos.side_to_move());
+    CheckInfo ci(pos);
 
     // Loop through all the moves in the root move list
     for (int i = 0; i <  rml.move_count() && !AbortSearch; i++)
@@ -900,11 +900,11 @@ namespace {
         // Decide search depth for this move
         bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
         bool dangerous;
-        ext = extension(pos, move, Depth(100), true, captureOrPromotion, pos.move_is_check(move), false, false, &dangerous);
+        ext = extension(pos, move, true, captureOrPromotion, pos.move_is_check(move), false, false, &dangerous);
         newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
 
         // Make the move, and search it
-        pos.do_move(move, st, dcCandidates);
+        pos.do_move(move, st, ci.dcCandidates);
 
         if (i < MultiPV)
         {
@@ -1065,7 +1065,6 @@ namespace {
     Move movesSearched[256];
     EvalInfo ei;
     StateInfo st;
-    Bitboard dcCandidates;
     const TTEntry* tte;
     Move ttMove, move;
     Depth ext, newDepth;
@@ -1114,7 +1113,7 @@ namespace {
     // to search all moves
     isCheck = pos.is_check();
     mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move()));
-    dcCandidates = pos.discovered_check_candidates(pos.side_to_move());
+    CheckInfo ci(pos);
     MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
 
     // Loop through all legal moves until no moves remain or a beta cutoff
@@ -1126,17 +1125,17 @@ namespace {
       assert(move_is_ok(move));
 
       singleReply = (isCheck && mp.number_of_evasions() == 1);
-      moveIsCheck = pos.move_is_check(move, dcCandidates);
+      moveIsCheck = pos.move_is_check(move, ci);
       captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       movesSearched[moveCount++] = ss[ply].currentMove = move;
 
       // Decide the new search depth
-      ext = extension(pos, move, depth, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
+      ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
       newDepth = depth - OnePly + ext;
 
       // Make and search the move
-      pos.do_move(move, st, dcCandidates);
+      pos.do_move(move, st, ci.dcCandidates, moveIsCheck);
 
       if (moveCount == 1) // The first move in list is the PV
           value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID);
@@ -1210,7 +1209,7 @@ namespace {
           && !AbortSearch
           && !thread_should_stop(threadID)
           && split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE, VALUE_NONE, depth,
-                   &moveCount, &mp, dcCandidates, threadID, true))
+                   &moveCount, &mp, ci.dcCandidates, threadID, true))
           break;
     }
 
@@ -1257,7 +1256,6 @@ namespace {
     Move movesSearched[256];
     EvalInfo ei;
     StateInfo st;
-    Bitboard dcCandidates;
     const TTEntry* tte;
     Move ttMove, move;
     Depth ext, newDepth;
@@ -1371,7 +1369,7 @@ namespace {
     // Initialize a MovePicker object for the current position, and prepare
     // to search all moves.
     MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
-    dcCandidates = pos.discovered_check_candidates(pos.side_to_move());
+    CheckInfo ci(pos);
     futilityValue = VALUE_NONE;
     useFutilityPruning = depth < SelectiveDepth && !isCheck;
 
@@ -1388,13 +1386,13 @@ namespace {
       assert(move_is_ok(move));
 
       singleReply = (isCheck && mp.number_of_evasions() == 1);
-      moveIsCheck = pos.move_is_check(move, dcCandidates);
+      moveIsCheck = pos.move_is_check(move, ci);
       captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       movesSearched[moveCount++] = ss[ply].currentMove = move;
 
       // Decide the new search depth
-      ext = extension(pos, move, depth, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
+      ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
       newDepth = depth - OnePly + ext;
 
       // Futility pruning
@@ -1425,7 +1423,7 @@ namespace {
       }
 
       // Make and search the move
-      pos.do_move(move, st, dcCandidates);
+      pos.do_move(move, st, ci.dcCandidates, moveIsCheck);
 
       // Try to reduce non-pv search depth by one ply if move seems not problematic,
       // if the move fails high will be re-searched at full depth.
@@ -1471,7 +1469,7 @@ namespace {
           && !AbortSearch
           && !thread_should_stop(threadID)
           && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, approximateEval, depth, &moveCount,
-                   &mp, dcCandidates, threadID, false))
+                   &mp, ci.dcCandidates, threadID, false))
         break;
     }
 
@@ -1520,10 +1518,9 @@ namespace {
 
     EvalInfo ei;
     StateInfo st;
-    Bitboard dcCandidates;
     Move ttMove, move;
     Value staticValue, bestValue, value, futilityValue;
-    bool isCheck, enoughMaterial;
+    bool isCheck, enoughMaterial, moveIsCheck;
     const TTEntry* tte = NULL;
     int moveCount = 0;
     bool pvNode = (beta - alpha != 1);
@@ -1592,7 +1589,7 @@ namespace {
     // to search the moves.  Because the depth is <= 0 here, only captures,
     // queen promotions and checks (only if depth == 0) will be generated.
     MovePicker mp = MovePicker(pos, ttMove, depth, H);
-    dcCandidates = pos.discovered_check_candidates(pos.side_to_move());
+    CheckInfo ci(pos);
     enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
 
     // Loop through the moves until no moves remain or a beta cutoff
@@ -1605,12 +1602,14 @@ namespace {
       moveCount++;
       ss[ply].currentMove = move;
 
+      moveIsCheck = pos.move_is_check(move, ci);
+
       // Futility pruning
       if (   enoughMaterial
           && !isCheck
           && !pvNode
+          && !moveIsCheck
           && !move_is_promotion(move)
-          && !pos.move_is_check(move, dcCandidates)
           && !pos.move_is_passed_pawn_push(move))
       {
           futilityValue =  staticValue
@@ -1636,7 +1635,7 @@ namespace {
           continue;
 
       // Make and search the move
-      pos.do_move(move, st, dcCandidates);
+      pos.do_move(move, st, ci.dcCandidates, moveIsCheck);
       value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
       pos.undo_move(move);
 
@@ -1698,6 +1697,7 @@ namespace {
     assert(ActiveThreads > 1);
 
     Position pos = Position(sp->pos);
+    CheckInfo ci(pos);
     SearchStack* ss = sp->sstack[threadID];
     Value value;
     Move move;
@@ -1711,7 +1711,7 @@ namespace {
     {
       assert(move_is_ok(move));
 
-      bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
+      bool moveIsCheck = pos.move_is_check(move, ci);
       bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       lock_grab(&(sp->lock));
@@ -1722,7 +1722,7 @@ namespace {
 
       // Decide the new search depth.
       bool dangerous;
-      Depth ext = extension(pos, move, sp->depth, false, captureOrPromotion, moveIsCheck, false, false, &dangerous);
+      Depth ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, false, false, &dangerous);
       Depth newDepth = sp->depth - OnePly + ext;
 
       // Prune?
@@ -1762,7 +1762,7 @@ namespace {
 
       // Make and search the move.
       StateInfo st;
-      pos.do_move(move, st, sp->dcCandidates);
+      pos.do_move(move, st, sp->dcCandidates, moveIsCheck);
 
       // Try to reduce non-pv search depth by one ply if move seems not problematic,
       // if the move fails high will be re-searched at full depth.
@@ -1841,6 +1841,7 @@ namespace {
     assert(ActiveThreads > 1);
 
     Position pos = Position(sp->pos);
+    CheckInfo ci(pos);
     SearchStack* ss = sp->sstack[threadID];
     Value value;
     Move move;
@@ -1849,7 +1850,7 @@ namespace {
            && !thread_should_stop(threadID)
            && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
     {
-      bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
+      bool moveIsCheck = pos.move_is_check(move, ci);
       bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       assert(move_is_ok(move));
@@ -1862,12 +1863,12 @@ namespace {
 
       // Decide the new search depth.
       bool dangerous;
-      Depth ext = extension(pos, move, sp->depth, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
+      Depth ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
       Depth newDepth = sp->depth - OnePly + ext;
 
       // Make and search the move.
       StateInfo st;
-      pos.do_move(move, st, sp->dcCandidates);
+      pos.do_move(move, st, sp->dcCandidates, moveIsCheck);
 
       // Try to reduce non-pv search depth by one ply if move seems not problematic,
       // if the move fails high will be re-searched at full depth.
@@ -2298,7 +2299,7 @@ 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, Depth depth, bool pvNode, bool captureOrPromotion,
+  Depth extension(const Position& pos, Move m, bool pvNode, bool captureOrPromotion,
                   bool check, bool singleReply, bool mateThreat, bool* dangerous) {
 
     assert(m != MOVE_NONE);
@@ -2318,19 +2319,6 @@ namespace {
             result += MateThreatExtension[pvNode];
     }
 
-    if (   pvNode
-        && captureOrPromotion
-        && pos.type_of_piece_on(move_to(m)) != PAWN
-        && pos.see_sign(m) >= 0)
-    {
-        result += OnePly/2;
-        *dangerous = true;
-    }
-
-    // Do not extend at low depths
-    if (!pvNode && depth < 4*OnePly)
-        return Min(result, OnePly); // Further test with Min(result, OnePly / 2)
-
     if (pos.type_of_piece_on(move_from(m)) == PAWN)
     {
         Color c = pos.side_to_move();
@@ -2357,6 +2345,15 @@ namespace {
         *dangerous = true;
     }
 
+    if (   pvNode
+        && captureOrPromotion
+        && pos.type_of_piece_on(move_to(m)) != PAWN
+        && pos.see_sign(m) >= 0)
+    {
+        result += OnePly/2;
+        *dangerous = true;
+    }
+
     return Min(result, OnePly);
   }