X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=7fe8971b349ce7efeb41e021b93665571a482a7c;hp=a3143598171d666668b03d5989d5df4693fdb87a;hb=b48439e90643cb6f65f9e34d1421976883c12efc;hpb=d490bb99734bd6e2f8a0a352d2f3f1ba264ece66

diff --git a/src/movepick.cpp b/src/movepick.cpp
index a3143598..7fe8971b 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -34,27 +34,30 @@ namespace {
     QSEARCH_RECAPTURES, QRECAPTURES
   };
 
-  // Our insertion sort, which is guaranteed to be stable, as it should be
-  void insertion_sort(ExtMove* begin, ExtMove* end)
-  {
-    ExtMove tmp, *p, *q;
-
-    for (p = begin + 1; p < end; ++p)
-    {
-        tmp = *p;
-        for (q = p; q != begin && *(q-1) < tmp; --q)
-            *q = *(q-1);
-        *q = tmp;
-    }
+  // partial_insertion_sort() sorts moves in descending order up to and including
+  // a given limit. The order of moves smaller than the limit is left unspecified.
+  // To keep the implementation simple, *begin is always included in the sorted moves.
+  void partial_insertion_sort(ExtMove* begin, ExtMove* end, int limit) {
+
+    for (ExtMove *sortedEnd = begin + 1, *p = begin + 1; p < end; ++p)
+        if (p->value >= limit)
+        {
+            ExtMove tmp = *p, *q;
+            *p = *sortedEnd;
+            for (q = sortedEnd; q != begin && *(q-1) < tmp; --q)
+                *q = *(q-1);
+            *q = tmp;
+            ++sortedEnd;
+        }
   }
 
   // pick_best() finds the best move in the range (begin, end) and moves it to
   // the front. It's faster than sorting all the moves in advance when there
   // are few moves, e.g., the possible captures.
-  Move pick_best(ExtMove* begin, ExtMove* end)
-  {
-      std::swap(*begin, *std::max_element(begin, end));
-      return *begin;
+  Move pick_best(ExtMove* begin, ExtMove* end) {
+
+    std::swap(*begin, *std::max_element(begin, end));
+    return *begin;
   }
 
 } // namespace
@@ -115,7 +118,7 @@ MovePicker::MovePicker(const Position& p, Move ttm, Value th)
   ttMove =   ttm
           && pos.pseudo_legal(ttm)
           && pos.capture(ttm)
-          && pos.see_ge(ttm, threshold)? ttm : MOVE_NONE;
+          && pos.see_ge(ttm, threshold) ? ttm : MOVE_NONE;
 
   stage += (ttMove == MOVE_NONE);
 }
@@ -142,16 +145,16 @@ void MovePicker::score<QUIETS>() {
 
   const HistoryStats& history = pos.this_thread()->history;
 
-  const CounterMoveStats* cmh = (ss-1)->counterMoves;
-  const CounterMoveStats* fmh = (ss-2)->counterMoves;
-  const CounterMoveStats* fmh2 = (ss-4)->counterMoves;
+  const CounterMoveStats& cmh = *(ss-1)->counterMoves;
+  const CounterMoveStats& fmh = *(ss-2)->counterMoves;
+  const CounterMoveStats& fm2 = *(ss-4)->counterMoves;
 
   Color c = pos.side_to_move();
 
   for (auto& m : *this)
-      m.value =   (*cmh)[pos.moved_piece(m)][to_sq(m)]
-               +  (*fmh)[pos.moved_piece(m)][to_sq(m)]
-               + (*fmh2)[pos.moved_piece(m)][to_sq(m)]
+      m.value =  cmh[pos.moved_piece(m)][to_sq(m)]
+               + fmh[pos.moved_piece(m)][to_sq(m)]
+               + fm2[pos.moved_piece(m)][to_sq(m)]
                + history.get(c, m);
 }
 
@@ -175,7 +178,7 @@ void MovePicker::score<EVASIONS>() {
 /// left. It picks the move with the biggest value from a list of generated moves
 /// taking care not to return the ttMove if it has already been searched.
 
-Move MovePicker::next_move() {
+Move MovePicker::next_move(bool skipQuiets) {
 
   Move move;
 
@@ -238,19 +241,15 @@ Move MovePicker::next_move() {
       cur = endBadCaptures;
       endMoves = generate<QUIETS>(pos, cur);
       score<QUIETS>();
-      if (depth < 3 * ONE_PLY)
-      {
-          ExtMove* goodQuiet = std::partition(cur, endMoves, [](const ExtMove& m)
-                                             { return m.value > VALUE_ZERO; });
-          insertion_sort(cur, goodQuiet);
-      } else
-          insertion_sort(cur, endMoves);
+      partial_insertion_sort(cur, endMoves, -4000 * depth / ONE_PLY);
       ++stage;
 
   case QUIET:
-      while (cur < endMoves)
+      while (    cur < endMoves
+             && (!skipQuiets || cur->value >= VALUE_ZERO))
       {
           move = *cur++;
+
           if (   move != ttMove
               && move != ss->killers[0]
               && move != ss->killers[1]