There is no need to special case KNNK ending

[stockfish] / src / material.cpp

diff --git a/src/material.cpp b/src/material.cpp
index eb271e8c94b6701c7eab1a308a451454f242cd76..a8ecb51a5a3377a6a7153951e4e13c53e89c528a 100644 (file)
--- a/src/material.cpp
+++ b/src/material.cpp
@@ -41,17 +41,17 @@ namespace {
   const Value BishopPairEndgameBonus = Value(97);
 
   // Polynomial material balance parameters
-  const Value RedundantQueenPenalty = Value(358);
-  const Value RedundantRookPenalty  = Value(536);
-  const int LinearCoefficients[6]   = { 1740, -146, -1246, -197, 206, -7 };
+  const Value RedundantQueenPenalty = Value(320);
+  const Value RedundantRookPenalty  = Value(554);
+  const int LinearCoefficients[6]   = { 1709, -137, -1185, -166, 141, 59 };
 
   const int QuadraticCoefficientsSameColor[][6] = {
-  { 0, 0, 0, 0, 0, 0 }, { 31, -4, 0, 0, 0, 0 }, { 14, 267, -21, 0, 0, 0 },
-  { 0, 7, -26, 0, 0, 0 }, { -3, -1, 69, 162, 80, 0 }, { 40, 27, 119, 174, -64, -49 } };
+  { 0, 0, 0, 0, 0, 0 }, { 33, -6, 0, 0, 0, 0 }, { 29, 269, -12, 0, 0, 0 },
+  { 0, 19, -4, 0, 0, 0 }, { -35, -10, 40, 95, 50, 0 }, { 52, 23, 78, 144, -11, -33 } };
 
   const int QuadraticCoefficientsOppositeColor[][6] = {
-  { 0, 0, 0, 0, 0, 0 }, { -9, 0, 0, 0, 0, 0 }, { 49, 32, 0, 0, 0, 0 },
-  { -25, 19, -5, 0, 0, 0 }, { 97, -6, 39, -88, 0, 0 }, { 77, 69, -42, 104, 116, 0 } };
+  { 0, 0, 0, 0, 0, 0 }, { -5, 0, 0, 0, 0, 0 }, { -33, 23, 0, 0, 0, 0 },
+  { 17, 25, -3, 0, 0, 0 }, { 10, -2, -19, -67, 0, 0 }, { 69, 64, -41, 116, 137, 0 } };
 
   // Unmapped endgame evaluation and scaling functions, these
   // are accessed direcly and not through the function maps.
@@ -61,8 +61,6 @@ namespace {
   ScalingFunction<KQKRP>    ScaleKQKRP(WHITE),  ScaleKRPKQ(BLACK);
   ScalingFunction<KPsK>     ScaleKPsK(WHITE),   ScaleKKPs(BLACK);
   ScalingFunction<KPKP>     ScaleKPKPw(WHITE),  ScaleKPKPb(BLACK);
-
-  Key KNNKMaterialKey, KKNNMaterialKey;
 }
 
 
@@ -157,14 +155,6 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) {
   mi->clear();
   mi->key = key;
 
-  // A special case before looking for a specialized evaluation function
-  // KNN vs K is a draw.
-  if (key == KNNKMaterialKey || key == KKNNMaterialKey)
-  {
-      mi->factor[WHITE] = mi->factor[BLACK] = 0;
-      return mi;
-  }
-
   // Let's look if we have a specialized evaluation function for this
   // particular material configuration. First we look for a fixed
   // configuration one, then a generic one if previous search failed.
@@ -348,9 +338,7 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) {
 
 EndgameFunctions::EndgameFunctions() {
 
-  KNNKMaterialKey = buildKey("KNNK");
-  KKNNMaterialKey = buildKey("KKNN");
-
+  add<EvaluationFunction<KNNK>  >("KNNK");
   add<EvaluationFunction<KPK>   >("KPK");
   add<EvaluationFunction<KBNK>  >("KBNK");
   add<EvaluationFunction<KRKP>  >("KRKP");