X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=19785b64ab027606e138a44da71c16f8d12442b7;hp=582978e69d0c3f1fb2c6535c82d71f564cc85aa7;hb=df7cd94aeeb4e99bed2d46c008efdd5e24085e0f;hpb=c7866a4215c31d7d0af8e8550fbf8c13f6ea1d1a

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 582978e6..19785b64 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2009 Marco Costalba
+  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -71,10 +71,11 @@ namespace {
 /// move ordering is at the current node.
 
 MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
-                       const History& h, SearchStack* ss) : pos(p), H(h) {
+                       const History& h, SearchStack* ss, Value beta) : pos(p), H(h) {
   int searchTT = ttm;
   ttMoves[0].move = ttm;
   lastBadCapture = badCaptures;
+  badCaptureThreshold = 0;
 
   pinned = p.pinned_pieces(pos.side_to_move());
 
@@ -90,8 +91,14 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
   if (p.is_check())
       phasePtr = EvasionsPhaseTable;
   else if (d > Depth(0))
+  {
+      // Consider sligtly negative captures as good if at low
+      // depth and far from beta.
+      if (ss && ss->eval < beta - PawnValueMidgame && d < 3 * OnePly)
+          badCaptureThreshold = -PawnValueMidgame;
+
       phasePtr = MainSearchPhaseTable;
-  else if (d == Depth(0))
+  } else if (d == Depth(0))
       phasePtr = QsearchWithChecksPhaseTable;
   else
   {
@@ -104,7 +111,7 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
           searchTT = ttMoves[0].move = MOVE_NONE;
   }
 
-  phasePtr += !searchTT - 1;
+  phasePtr += int(!searchTT) - 1;
   go_next_phase();
 }
 
@@ -213,6 +220,7 @@ void MovePicker::score_noncaptures() {
   Move m;
   Piece piece;
   Square from, to;
+  int hs;
 
   for (MoveStack* cur = moves; cur != lastMove; cur++)
   {
@@ -220,7 +228,14 @@ void MovePicker::score_noncaptures() {
       from = move_from(m);
       to = move_to(m);
       piece = pos.piece_on(from);
-      cur->score = H.move_ordering_score(piece, to);
+      hs = H.move_ordering_score(piece, to);
+
+      // Ensure history has always highest priority
+      if (hs > 0)
+          hs += 10000;
+
+      // Gain table based scoring
+      cur->score = hs + 16 * H.gain(piece, to);
   }
 }
 
@@ -282,7 +297,7 @@ Move MovePicker::get_next_move() {
               {
                   // Check for a non negative SEE now
                   int seeValue = pos.see_sign(move);
-                  if (seeValue >= 0)
+                  if (seeValue >= badCaptureThreshold)
                       return move;
 
                   // Losing capture, move it to the badCaptures[] array, note