Remove pawncount array in imbalance

This is a natural follow up to last commit where values on the
QuadraticOurs diagonal and some piece value deltas were changed.
@Stefano80 tried to simplify the newly introduced pawncount array
using QuadraticOurs[1][1] =52 and a -30 adjustment on pawn values

His STC [-3,1] was green
http://tests.stockfishchess.org/tests/view/5b707f5b0ebc5902bdba2745
but not his LTC[-3,1]
http://tests.stockfishchess.org/tests/view/5b7095700ebc5902bdba2a49

So I started a 80000 30+0.3 SPSA on the QuadraticOurs diagonal and
on the piece values using @Stefano80 start values.

SPSA gave the new values QuadraticOurs[1][1] =38 and a -33 on pawn
values (the other changes on QuadraticOurs were kept, but were not
ignificant according to this test
http://tests.stockfishchess.org/tests/view/5b710ccb0ebc5902bdba2f27)

STC
http://tests.stockfishchess.org/tests/view/5b710b220ebc5902bdba2f19
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 50902 W: 11214 L: 11150 D: 28538

LTC
http://tests.stockfishchess.org/tests/view/5b7124ef0ebc5902bdba3106
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 34271 W: 5852 L: 5753 D: 22666

Closes https://github.com/official-stockfish/Stockfish/pull/1735

bench: 4738555

diff --git a/src/material.cpp b/src/material.cpp
index d98eb125e4bb5f84c8ebda36b1d146b20f5fdb41..ef7bb14333aa51b0190f19264c30abe268ef3839 100644 (file)
--- a/src/material.cpp
+++ b/src/material.cpp
@@ -34,12 +34,12 @@ namespace {
   constexpr int QuadraticOurs[][PIECE_TYPE_NB] = {
     //            OUR PIECES
     // pair pawn knight bishop rook queen
-    {1443                               }, // Bishop pair
-    {  40,    0                         }, // Pawn
-    {  32,  255, -67                    }, // Knight      OUR PIECES
+    {1438                               }, // Bishop pair
+    {  40,   38                         }, // Pawn
+    {  32,  255, -62                    }, // Knight      OUR PIECES
     {   0,  104,   4,    0              }, // Bishop
-    { -26,   -2,  47,   105,  -221      }, // Rook
-    {-189,   24, 117,   133,  -134, -10 }  // Queen
+    { -26,   -2,  47,   105,  -208      }, // Rook
+    {-189,   24, 117,   133,  -134, -6  }  // Queen
   };
 
   constexpr int QuadraticTheirs[][PIECE_TYPE_NB] = {
@@ -53,8 +53,6 @@ namespace {
     {  97,  100, -42,   137,  268,    0 }  // Queen
   };
 
-  constexpr int PawnCount[] = { 0, 304,  144, -320, -560, -704, -672, -464, -320 };
-
   // Endgame evaluation and scaling functions are accessed directly and not through
   // the function maps because they correspond to more than one material hash key.
   Endgame<KXK>    EvaluateKXK[] = { Endgame<KXK>(WHITE),    Endgame<KXK>(BLACK) };
@@ -79,7 +77,7 @@ namespace {
   bool is_KQKRPs(const Position& pos, Color us) {
     return  !pos.count<PAWN>(us)
           && pos.non_pawn_material(us) == QueenValueMg
-          && pos.count<QUEEN>(us)  == 1
+          && pos.count<QUEEN>(us) == 1
           && pos.count<ROOK>(~us) == 1
           && pos.count<PAWN>(~us) >= 1;
   }
@@ -91,7 +89,7 @@ namespace {
 
     constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
 
-    int bonus = PawnCount[pieceCount[Us][PAWN]];
+    int bonus = 0;
 
     // Second-degree polynomial material imbalance, by Tord Romstad
     for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)

diff --git a/src/types.h b/src/types.h
index fdf7ba93dc63a017ce136b369d79b891b3dfb8d8..c9c988bae190c49a17f3e1c670c3fdba77ee7ba2 100644 (file)
--- a/src/types.h
+++ b/src/types.h
@@ -182,11 +182,11 @@ enum Value : int {
   VALUE_MATE_IN_MAX_PLY  =  VALUE_MATE - 2 * MAX_PLY,
   VALUE_MATED_IN_MAX_PLY = -VALUE_MATE + 2 * MAX_PLY,
 
-  PawnValueMg   = 175,   PawnValueEg   = 240,
+  PawnValueMg   = 142,   PawnValueEg   = 207,
   KnightValueMg = 784,   KnightValueEg = 868,
-  BishopValueMg = 831,   BishopValueEg = 919,
+  BishopValueMg = 828,   BishopValueEg = 916,
   RookValueMg   = 1286,  RookValueEg   = 1378,
-  QueenValueMg  = 2527,  QueenValueEg  = 2697,
+  QueenValueMg  = 2528,  QueenValueEg  = 2698,
 
   MidgameLimit  = 15258, EndgameLimit  = 3915
 };