Revert refinedValue in ProbCut

It seems much worst in number of nodes seacrhed to reach
the depth and anyhow does not give any advantage to the
Onno's oroginal one.

So revert by now and perhaps readd when we find something
clearly better.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 7d759f12691058f255f84784e388a09b4fad6c09..61e5527f42c61d638132201f0b2f2efd18bc999a 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -110,13 +110,13 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h)
   go_next_phase();
 }
 
   go_next_phase();
 }
 

-MovePicker::MovePicker(const Position& p, Move ttm, const History& h, int threshold)
+MovePicker::MovePicker(const Position& p, Move ttm, const History& h, int parentCapture)

                        : pos(p), H(h) {
 
   assert (!pos.in_check());
 
   // In ProbCut we consider only captures better than parent's move
                        : pos(p), H(h) {
 
   assert (!pos.in_check());
 
   // In ProbCut we consider only captures better than parent's move

-  captureThreshold = threshold;
+  captureThreshold = parentCapture;

   phasePtr = ProbCutTable;
 
   if (   ttm != MOVE_NONE
   phasePtr = ProbCutTable;
 
   if (   ttm != MOVE_NONE

diff --git a/src/movepick.h b/src/movepick.h
index 5e4cf7796f0b2214f509740665f490bd4cfd9518..d0ced0474ffd901e6b34275acf520147001fe506 100644 (file)
--- a/src/movepick.h
+++ b/src/movepick.h
@@ -42,7 +42,7 @@ class MovePicker {
 public:
   MovePicker(const Position&, Move, Depth, const History&, SearchStack*, Value);
   MovePicker(const Position&, Move, Depth, const History&);
 public:
   MovePicker(const Position&, Move, Depth, const History&, SearchStack*, Value);
   MovePicker(const Position&, Move, Depth, const History&);

-  MovePicker(const Position&, Move, const History&, int threshold);
+  MovePicker(const Position&, Move, const History&, int parentCapture);

   Move get_next_move();
 
 private:
   Move get_next_move();
 
 private:

diff --git a/src/position.h b/src/position.h
index 1a7149070f3c0640ab8b87e56a3f5df14140eec3..6c48b54c341676f98a58243a7f42869e2a69e74b 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -213,6 +213,7 @@ public:
   // Static exchange evaluation
   int see(Move m) const;
   int see_sign(Move m) const;
   // Static exchange evaluation
   int see(Move m) const;
   int see_sign(Move m) const;

+  static int see_value(PieceType pt);

 
   // Accessing hash keys
   Key get_key() const;
 
   // Accessing hash keys
   Key get_key() const;


@@ -466,6 +467,10 @@ inline bool Position::square_is_weak(Square s, Color c) const {
   return !(pieces(PAWN, opposite_color(c)) & attack_span_mask(c, s));
 }
 
   return !(pieces(PAWN, opposite_color(c)) & attack_span_mask(c, s));
 }
 

+inline int Position::see_value(PieceType pt) {
+  return seeValues[pt];
+}
+

 inline Key Position::get_key() const {
   return st->key;
 }
 inline Key Position::get_key() const {
   return st->key;
 }

diff --git a/src/search.cpp b/src/search.cpp
index 6e440702c9d69fc4ff26efa8fa982b2a565ecc1f..ec2b1c9cee1d09ce1637bd9bed7d8b7a2e65ed0a 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -903,8 +903,9 @@ namespace {
     }
 
     // Step 9. ProbCut (is omitted in PV nodes)
     }
 
     // Step 9. ProbCut (is omitted in PV nodes)

-    // If we have a good capture that raises the score well above beta and a reduced
-    // search confirms the score then we can (almost) safely prune the previous move.
+    // If we have a very good capture (i.e. SEE > seeValues[captured_piece_type])
+    // and a reduced search returns a value much above beta, we can (almost) safely
+    // prune the previous move.

     if (   !PvNode
         &&  depth >= RazorDepth + ONE_PLY
         && !inCheck
     if (   !PvNode
         &&  depth >= RazorDepth + ONE_PLY
         && !inCheck


@@ -917,7 +918,7 @@ namespace {
 
         assert(rdepth >= ONE_PLY);
 
 
         assert(rdepth >= ONE_PLY);
 

-        MovePicker mp(pos, ttMove, H, Max(rbeta - refinedValue, VALUE_ZERO));
+        MovePicker mp(pos, ttMove, H, Position::see_value(pos.captured_piece_type()));

         pinned = pos.pinned_pieces(pos.side_to_move());
 
         while ((move = mp.get_next_move()) != MOVE_NONE)
         pinned = pos.pinned_pieces(pos.side_to_move());
 
         while ((move = mp.get_next_move()) != MOVE_NONE)