Simplify captures ordering

A big simplification and removing of useless code.

Finished at 50% both at short TC (with SPRT) than
at long TC at fixed number of games:
ELO: -0.14 +-3.4 (95%) LOS: 46.8%
Total: 15206 W: 2836 L: 2842 D: 9528

bench: 5059948

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 8445260b58e612b5185f8fe84a91d41c264fc7a0..4f2fa01eb231ba64e10feaba33d1af33977a35be 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -70,12 +70,11 @@ namespace {
 /// search captures, promotions and some checks) and about how important good
 /// move ordering is at the current node.
 
 /// search captures, promotions and some checks) and about how important good
 /// move ordering is at the current node.
 

-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h, Move* cm,
-                       Search::Stack* s, Value beta) : pos(p), history(h), depth(d) {
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
+                       Move* cm, Search::Stack* s) : pos(p), history(h), depth(d) {

 
   assert(d > DEPTH_ZERO);
 
 
   assert(d > DEPTH_ZERO);
 

-  captureThreshold = 0;

   cur = end = moves;
   endBadCaptures = moves + MAX_MOVES - 1;
   countermoves = cm;
   cur = end = moves;
   endBadCaptures = moves + MAX_MOVES - 1;
   countermoves = cm;


@@ -85,18 +84,8 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats&
       stage = EVASION;
 
   else
       stage = EVASION;
 
   else

-  {

       stage = MAIN_SEARCH;
 
       stage = MAIN_SEARCH;
 

-      // Consider sligtly negative captures as good if at low depth and far from beta
-      if (ss->staticEval < beta - PawnValueMg && d < 3 * ONE_PLY)
-          captureThreshold = -PawnValueMg;
-
-      // Consider negative captures as good if still enough to reach beta
-      else if (ss->staticEval > beta)
-          captureThreshold = beta - ss->staticEval;
-  }
-

   ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
   end += (ttMove != MOVE_NONE);
 }
   ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
   end += (ttMove != MOVE_NONE);
 }


@@ -317,9 +306,7 @@ Move MovePicker::next_move<false>() {
           move = pick_best(cur++, end)->move;
           if (move != ttMove)
           {
           move = pick_best(cur++, end)->move;
           if (move != ttMove)
           {

-              assert(captureThreshold <= 0); // Otherwise we cannot use see_sign()
-
-              if (pos.see_sign(move) >= captureThreshold)
+              if (pos.see_sign(move) >= 0)

                   return move;
 
               // Losing capture, move it to the tail of the array
                   return move;
 
               // Losing capture, move it to the tail of the array

diff --git a/src/movepick.h b/src/movepick.h
index 363b1a1b32327dfb442999a11b8400915460e44e..572025f20e0edb936f8dba3b7df4eb74dc2013cf 100644 (file)
--- a/src/movepick.h
+++ b/src/movepick.h
@@ -86,7 +86,7 @@ class MovePicker {
 public:
   MovePicker(const Position&, Move, Depth, const HistoryStats&, Square);
   MovePicker(const Position&, Move, const HistoryStats&, PieceType);
 public:
   MovePicker(const Position&, Move, Depth, const HistoryStats&, Square);
   MovePicker(const Position&, Move, const HistoryStats&, PieceType);

-  MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Search::Stack*, Value);
+  MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Search::Stack*);

 
   template<bool SpNode> Move next_move();
 
 
   template<bool SpNode> Move next_move();
 

diff --git a/src/search.cpp b/src/search.cpp
index 3985ad3049c6ba3d747c4285fceabbd6c5382cdb..c6bc8e372bcd28d4c02c8b2a6ccd1b22a3e4a6e8 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -762,7 +762,7 @@ moves_loop: // When in check and at SpNode search starts from here
     Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first,
                             Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second };
 
     Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first,
                             Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second };
 

-    MovePicker mp(pos, ttMove, depth, History, countermoves, ss, PvNode ? -VALUE_INFINITE : beta);
+    MovePicker mp(pos, ttMove, depth, History, countermoves, ss);

     CheckInfo ci(pos);
     value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
     singularExtensionNode =   !RootNode
     CheckInfo ci(pos);
     value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
     singularExtensionNode =   !RootNode