Tweak cutnode reduction

[stockfish] / src / material.cpp

diff --git a/src/material.cpp b/src/material.cpp
index 773f332f20fddfdcebfacf441af9b2f18b19bd82..bb25d3caa7e0e9c9ce78382e030012ec4dfd5e17 100644 (file)
--- a/src/material.cpp
+++ b/src/material.cpp
@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2020 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
@@ -18,7 +18,6 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <algorithm> // For std::min
 #include <cassert>
 #include <cstring>   // For std::memset
 
@@ -45,12 +44,12 @@ namespace {
   constexpr int QuadraticTheirs[][PIECE_TYPE_NB] = {
     //           THEIR PIECES
     // pair pawn knight bishop rook queen
-    {   0                               }, // Bishop pair
-    {  36,    0                         }, // Pawn
-    {   9,   63,   0                    }, // Knight      OUR PIECES
-    {  59,   65,  42,     0             }, // Bishop
-    {  46,   39,  24,   -24,    0       }, // Rook
-    {  97,  100, -42,   137,  268,    0 }  // Queen
+    {                                   }, // Bishop pair
+    {  36,                              }, // Pawn
+    {   9,   63,                        }, // Knight      OUR PIECES
+    {  59,   65,  42,                   }, // Bishop
+    {  46,   39,  24,   -24,            }, // Rook
+    {  97,  100, -42,   137,  268,      }  // Queen
   };
 
   // Endgame evaluation and scaling functions are accessed directly and not through
@@ -80,12 +79,14 @@ namespace {
           && pos.count<PAWN>(~us) >= 1;
   }
 
+
   /// imbalance() calculates the imbalance by comparing the piece count of each
   /// piece type for both colors.
+
   template<Color Us>
   int imbalance(const int pieceCount[][PIECE_TYPE_NB]) {
 
-    constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+    constexpr Color Them = ~Us;
 
     int bonus = 0;
 
@@ -95,9 +96,9 @@ namespace {
         if (!pieceCount[Us][pt1])
             continue;
 
-        int v = 0;
+        int v = QuadraticOurs[pt1][pt1] * pieceCount[Us][pt1];
 
-        for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
+        for (int pt2 = NO_PIECE_TYPE; pt2 < pt1; ++pt2)
             v +=  QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2]
                 + QuadraticTheirs[pt1][pt2] * pieceCount[Them][pt2];
 
@@ -111,6 +112,7 @@ namespace {
 
 namespace Material {
 
+
 /// Material::probe() looks up the current position's material configuration in
 /// the material hash table. It returns a pointer to the Entry if the position
 /// is found. Otherwise a new Entry is computed and stored there, so we don't
@@ -130,7 +132,7 @@ Entry* probe(const Position& pos) {
 
   Value npm_w = pos.non_pawn_material(WHITE);
   Value npm_b = pos.non_pawn_material(BLACK);
-  Value npm = std::max(EndgameLimit, std::min(npm_w + npm_b, MidgameLimit));
+  Value npm   = Utility::clamp(npm_w + npm_b, EndgameLimit, MidgameLimit);
 
   // Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME]
   e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit));
@@ -138,10 +140,10 @@ Entry* probe(const Position& pos) {
   // Let's look if we have a specialized evaluation function for this particular
   // material configuration. Firstly we look for a fixed configuration one, then
   // for a generic one if the previous search failed.
-  if ((e->evaluationFunction = pos.this_thread()->endgames.probe<Value>(key)) != nullptr)
+  if ((e->evaluationFunction = Endgames::probe<Value>(key)) != nullptr)
       return e;
 
-  for (Color c = WHITE; c <= BLACK; ++c)
+  for (Color c : { WHITE, BLACK })
       if (is_KXK(pos, c))
       {
           e->evaluationFunction = &EvaluateKXK[c];
@@ -150,9 +152,9 @@ Entry* probe(const Position& pos) {
 
   // OK, we didn't find any special evaluation function for the current material
   // configuration. Is there a suitable specialized scaling function?
-  const EndgameBase<ScaleFactor>* sf;
+  const auto* sf = Endgames::probe<ScaleFactor>(key);
 
-  if ((sf = pos.this_thread()->endgames.probe<ScaleFactor>(key)) != nullptr)
+  if (sf)
   {
       e->scalingFunction[sf->strongSide] = sf; // Only strong color assigned
       return e;
@@ -161,7 +163,7 @@ Entry* probe(const Position& pos) {
   // We didn't find any specialized scaling function, so fall back on generic
   // ones that refer to more than one material distribution. Note that in this
   // case we don't return after setting the function.
-  for (Color c = WHITE; c <= BLACK; ++c)
+  for (Color c : { WHITE, BLACK })
   {
     if (is_KBPsK(pos, c))
         e->scalingFunction[c] = &ScaleKBPsK[c];