Simplify Position::is_mate()

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index cdbd9f0d1963ff13486c986c401e340e1c960d03..3e72c0e9c88c1185f6eb1a03e44fa60cd2a1a160 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -867,8 +867,6 @@ void Position::do_capture_move(PieceType capture, Color them, Square to) {
     st->mgValue -= pst<MidGame>(them, capture, to);
     st->egValue -= pst<EndGame>(them, capture, to);
 
-    assert(!move_promotion(m) || capture != PAWN);
-
     // Update material
     if (capture != PAWN)
         npMaterial[them] -= piece_value_midgame(capture);
@@ -1869,21 +1867,6 @@ Value Position::compute_non_pawn_material(Color c) const {
 }
 
 
-/// Position::is_mate() returns true or false depending on whether the
-/// side to move is checkmated. Note that this function is currently very
-/// slow, and shouldn't be used frequently inside the search.
-
-bool Position::is_mate() const {
-
-  if (is_check())
-  {
-      MovePicker mp = MovePicker(*this, false, MOVE_NONE, EmptySearchStack, Depth(0));
-      return mp.get_next_move() == MOVE_NONE;
-  }
-  return false;
-}
-
-
 /// Position::is_draw() tests whether the position is drawn by material,
 /// repetition, or the 50 moves rule. It does not detect stalemates, this
 /// must be done by the search.
@@ -1908,6 +1891,17 @@ bool Position::is_draw() const {
 }
 
 
+/// Position::is_mate() returns true or false depending on whether the
+/// side to move is checkmated.
+
+bool Position::is_mate() const {
+
+  MoveStack moves[256];
+
+  return is_check() && !generate_evasions(*this, moves, pinned_pieces(sideToMove));
+}
+
+
 /// Position::has_mate_threat() tests whether a given color has a mate in one
 /// from the current position. This function is quite slow, but it doesn't
 /// matter, because it is currently only called from PV nodes, which are rare.