Retire linear imbalance

[stockfish] / src / material.h

diff --git a/src/material.h b/src/material.h
index 751edec90889de2f295751855268db15105702ac..bec2d662b7d970032d3f8b6eb4f17727c4088f11 100644 (file)
--- a/src/material.h
+++ b/src/material.h
@@ -1,7 +1,8 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, 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
@@ -17,7 +18,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(MATERIAL_H_INCLUDED)
+#ifndef MATERIAL_H_INCLUDED
 #define MATERIAL_H_INCLUDED
 
 #include "endgame.h"
@@ -28,50 +29,45 @@
 namespace Material {
 
 /// Material::Entry contains various information about a material configuration.
-/// It contains a material balance evaluation, a function pointer to a special
+/// It contains a material imbalance evaluation, a function pointer to a special
 /// endgame evaluation function (which in most cases is NULL, meaning that the
-/// standard evaluation function will be used), and "scale factors".
+/// standard evaluation function will be used), and scale factors.
 ///
-/// The scale factors are used to scale the evaluation score up or down.
-/// For instance, in KRB vs KR endgames, the score is scaled down by a factor
-/// of 4, which will result in scores of absolute value less than one pawn.
+/// The scale factors are used to scale the evaluation score up or down. For
+/// instance, in KRB vs KR endgames, the score is scaled down by a factor of 4,
+/// which will result in scores of absolute value less than one pawn.
 
 struct Entry {
 
-  Score material_value() const { return make_score(value, value); }
-  int space_weight() const { return spaceWeight; }
+  Score imbalance() const { return make_score(value, value); }
   Phase game_phase() const { return gamePhase; }
-  bool specialized_eval_exists() const { return evaluationFunction != NULL; }
-  Value evaluate(const Position& p) const { return (*evaluationFunction)(p); }
-  ScaleFactor scale_factor(const Position& pos, Color c) const;
+  bool specialized_eval_exists() const { return evaluationFunction != nullptr; }
+  Value evaluate(const Position& pos) const { return (*evaluationFunction)(pos); }
+
+  // scale_factor takes a position and a color as input and returns a scale factor
+  // for the given color. We have to provide the position in addition to the color
+  // because the scale factor may also be a function which should be applied to
+  // the position. For instance, in KBP vs K endgames, the scaling function looks
+  // for rook pawns and wrong-colored bishops.
+  ScaleFactor scale_factor(const Position& pos, Color c) const {
+    ScaleFactor sf = scalingFunction[c] ? (*scalingFunction[c])(pos)
+                                        :  SCALE_FACTOR_NONE;
+    return sf != SCALE_FACTOR_NONE ? sf : ScaleFactor(factor[c]);
+  }
 
   Key key;
   int16_t value;
   uint8_t factor[COLOR_NB];
   EndgameBase<Value>* evaluationFunction;
-  EndgameBase<ScaleFactor>* scalingFunction[COLOR_NB];
-  int spaceWeight;
+  EndgameBase<ScaleFactor>* scalingFunction[COLOR_NB]; // Could be one for each
+                                                       // side (e.g. KPKP, KBPsKs)
   Phase gamePhase;
 };
 
 typedef HashTable<Entry, 8192> Table;
 
-Entry* probe(const Position& pos, Table& entries, Endgames& endgames);
-Phase game_phase(const Position& pos);
+Entry* probe(const Position& pos);
 
-/// Material::scale_factor takes a position and a color as input, and
-/// returns a scale factor for the given color. We have to provide the
-/// position in addition to the color, because the scale factor need not
-/// to be a constant: It can also be a function which should be applied to
-/// the position. For instance, in KBP vs K endgames, a scaling function
-/// which checks for draws with rook pawns and wrong-colored bishops.
+} // namespace Material
 
-inline ScaleFactor Entry::scale_factor(const Position& pos, Color c) const {
-
-  return !scalingFunction[c] || (*scalingFunction[c])(pos) == SCALE_FACTOR_NONE
-        ? ScaleFactor(factor[c]) : (*scalingFunction[c])(pos);
-}
-
-}
-
-#endif // !defined(MATERIAL_H_INCLUDED)
+#endif // #ifndef MATERIAL_H_INCLUDED