X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmaterial.cpp;h=9873a44eb94c4dcf6205bbce3984a3eb3c5264de;hb=856a5f3aaaf8b9d53599963decacd4476b55c034;hp=9e46d05d4e74ffc237cc081458e628ffef9ba265;hpb=299afcd88653739b80691991f7e5072a0505f542;p=stockfish
diff --git a/src/material.cpp b/src/material.cpp
index 9e46d05d..9873a44e 100644
--- a/src/material.cpp
+++ b/src/material.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) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 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
@@ -17,36 +17,34 @@
along with this program. If not, see .
*/
-#include // For std::min
+#include // For std::min
#include
-#include
+#include // For std::memset
#include "material.h"
+#include "thread.h"
using namespace std;
namespace {
- // Values modified by Joona Kiiski
- const Value MidgameLimit = Value(15581);
- const Value EndgameLimit = Value(3998);
+ // Polynomial material imbalance parameters
- // Polynomial material balance parameters
+ // pair pawn knight bishop rook queen
+ const int Linear[6] = { 1852, -162, -1122, -183, 249, -154 };
- // pair pawn knight bishop rook queen
- const int LinearCoefficients[6] = { 1852, -162, -1122, -183, 249, -52 };
-
- const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = {
+ const int QuadraticOurs[][PIECE_TYPE_NB] = {
+ // OUR PIECES
// pair pawn knight bishop rook queen
{ 0 }, // Bishop pair
{ 39, 2 }, // Pawn
- { 35, 271, -4 }, // Knight
+ { 35, 271, -4 }, // Knight OUR PIECES
{ 0, 105, 4, 0 }, // Bishop
{ -27, -2, 46, 100, -141 }, // Rook
- { 58, 29, 83, 148, -163, 0 } // Queen
+ {-177, 25, 129, 142, -137, 0 } // Queen
};
- const int QuadraticCoefficientsOppositeColor[][PIECE_TYPE_NB] = {
+ const int QuadraticTheirs[][PIECE_TYPE_NB] = {
// THEIR PIECES
// pair pawn knight bishop rook queen
{ 0 }, // Bishop pair
@@ -54,165 +52,137 @@ namespace {
{ 10, 62, 0 }, // Knight OUR PIECES
{ 57, 64, 39, 0 }, // Bishop
{ 50, 40, 23, -22, 0 }, // Rook
- { 106, 101, 3, 151, 171, 0 } // Queen
+ { 98, 105, -39, 141, 274, 0 } // Queen
};
// 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 EvaluateKXK[] = { Endgame(WHITE), Endgame(BLACK) };
+ Endgame EvaluateKXK[] = { Endgame(WHITE), Endgame(BLACK) };
Endgame ScaleKBPsK[] = { Endgame(WHITE), Endgame(BLACK) };
Endgame ScaleKQKRPs[] = { Endgame(WHITE), Endgame(BLACK) };
Endgame ScaleKPsK[] = { Endgame(WHITE), Endgame(BLACK) };
Endgame ScaleKPKP[] = { Endgame(WHITE), Endgame(BLACK) };
- // Helper templates used to detect a given material distribution
- template bool is_KXK(const Position& pos) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- return !pos.count(Them)
- && pos.non_pawn_material(Them) == VALUE_ZERO
- && pos.non_pawn_material(Us) >= RookValueMg;
+ // Helper used to detect a given material distribution
+ bool is_KXK(const Position& pos, Color us) {
+ return !more_than_one(pos.pieces(~us))
+ && pos.non_pawn_material(us) >= RookValueMg;
}
- template bool is_KBPsKs(const Position& pos) {
- return pos.non_pawn_material(Us) == BishopValueMg
- && pos.count(Us) == 1
- && pos.count(Us) >= 1;
+ bool is_KBPsKs(const Position& pos, Color us) {
+ return pos.non_pawn_material(us) == BishopValueMg
+ && pos.count(us) == 1
+ && pos.count(us) >= 1;
}
- template bool is_KQKRPs(const Position& pos) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- return !pos.count(Us)
- && pos.non_pawn_material(Us) == QueenValueMg
- && pos.count(Us) == 1
- && pos.count(Them) == 1
- && pos.count(Them) >= 1;
+ bool is_KQKRPs(const Position& pos, Color us) {
+ return !pos.count(us)
+ && pos.non_pawn_material(us) == QueenValueMg
+ && pos.count(us) == 1
+ && pos.count(~us) == 1
+ && pos.count(~us) >= 1;
}
/// imbalance() calculates the imbalance by comparing the piece count of each
/// piece type for both colors.
-
template
int imbalance(const int pieceCount[][PIECE_TYPE_NB]) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- int pt1, pt2, pc, v;
- int value = 0;
+ int bonus = 0;
// Second-degree polynomial material imbalance by Tord Romstad
- for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
+ for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
{
- pc = pieceCount[Us][pt1];
- if (!pc)
+ if (!pieceCount[Us][pt1])
continue;
- v = LinearCoefficients[pt1];
+ int v = Linear[pt1];
- for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
- v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2]
- + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2];
+ for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
+ v += QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2]
+ + QuadraticTheirs[pt1][pt2] * pieceCount[Them][pt2];
- value += pc * v;
+ bonus += pieceCount[Us][pt1] * v;
}
- // Queen vs. 3 minors slightly favours the minors
- if (pieceCount[Us][QUEEN] == 1 && pieceCount[Them][QUEEN] == 0)
- {
- int n = pieceCount[Them][KNIGHT] - pieceCount[Us][KNIGHT];
- int b = pieceCount[Them][BISHOP] - pieceCount[Us][BISHOP];
-
- if ((n == 2 && b == 1) || (n == 1 && b == 2))
- value -= 66 * 16;
- }
-
- return value;
+ return bonus;
}
} // namespace
namespace Material {
-/// Material::probe() takes a position object as input, looks up a MaterialEntry
-/// object, and returns a pointer to it. If the material configuration is not
-/// already present in the table, it is computed and stored there, so we don't
-/// have to recompute everything when the same material configuration occurs again.
+/// 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
+/// have to recompute all when the same material configuration occurs again.
-Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
+Entry* probe(const Position& pos) {
Key key = pos.material_key();
- Entry* e = entries[key];
+ Entry* e = pos.this_thread()->materialTable[key];
- // If e->key matches the position's material hash key, it means that we
- // have analysed this material configuration before, and we can simply
- // return the information we found the last time instead of recomputing it.
if (e->key == key)
return e;
std::memset(e, 0, sizeof(Entry));
e->key = key;
e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL;
- e->gamePhase = game_phase(pos);
+ e->gamePhase = pos.game_phase();
// 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 (endgames.probe(key, e->evaluationFunction))
+ if (pos.this_thread()->endgames.probe(key, e->evaluationFunction))
return e;
- if (is_KXK(pos))
- {
- e->evaluationFunction = &EvaluateKXK[WHITE];
- return e;
- }
-
- if (is_KXK(pos))
- {
- e->evaluationFunction = &EvaluateKXK[BLACK];
- return e;
- }
+ for (Color c = WHITE; c <= BLACK; ++c)
+ if (is_KXK(pos, c))
+ {
+ e->evaluationFunction = &EvaluateKXK[c];
+ return e;
+ }
- // OK, we didn't find any special evaluation function for the current
- // material configuration. Is there a suitable scaling function?
- //
- // We face problems when there are several conflicting applicable
- // scaling functions and we need to decide which one to use.
+ // OK, we didn't find any special evaluation function for the current material
+ // configuration. Is there a suitable specialized scaling function?
EndgameBase* sf;
- if (endgames.probe(key, sf))
+ if (pos.this_thread()->endgames.probe(key, sf))
{
- e->scalingFunction[sf->color()] = sf;
+ e->scalingFunction[sf->strong_side()] = sf; // Only strong color assigned
return e;
}
- // Generic scaling functions that refer to more than one material
- // distribution. They should be probed after the specialized ones.
- // Note that these ones don't return after setting the function.
- if (is_KBPsKs(pos))
- e->scalingFunction[WHITE] = &ScaleKBPsK[WHITE];
-
- if (is_KBPsKs(pos))
- e->scalingFunction[BLACK] = &ScaleKBPsK[BLACK];
-
- if (is_KQKRPs(pos))
- e->scalingFunction[WHITE] = &ScaleKQKRPs[WHITE];
+ // 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)
+ {
+ if (is_KBPsKs(pos, c))
+ e->scalingFunction[c] = &ScaleKBPsK[c];
- else if (is_KQKRPs(pos))
- e->scalingFunction[BLACK] = &ScaleKQKRPs[BLACK];
+ else if (is_KQKRPs(pos, c))
+ e->scalingFunction[c] = &ScaleKQKRPs[c];
+ }
Value npm_w = pos.non_pawn_material(WHITE);
Value npm_b = pos.non_pawn_material(BLACK);
- if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN))
+ if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board
{
if (!pos.count(BLACK))
{
assert(pos.count(WHITE) >= 2);
+
e->scalingFunction[WHITE] = &ScaleKPsK[WHITE];
}
else if (!pos.count(WHITE))
{
assert(pos.count(BLACK) >= 2);
+
e->scalingFunction[BLACK] = &ScaleKPsK[BLACK];
}
else if (pos.count(WHITE) == 1 && pos.count(BLACK) == 1)
@@ -224,14 +194,16 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
}
}
- // No pawns makes it difficult to win, even with a material advantage. This
- // catches some trivial draws like KK, KBK and KNK and gives a very drawish
- // scale factor for cases such as KRKBP and KmmKm (except for KBBKN).
+ // Zero or just one pawn makes it difficult to win, even with a small material
+ // advantage. This catches some trivial draws like KK, KBK and KNK and gives a
+ // drawish scale factor for cases such as KRKBP and KmmKm (except for KBBKN).
if (!pos.count(WHITE) && npm_w - npm_b <= BishopValueMg)
- e->factor[WHITE] = uint8_t(npm_w < RookValueMg ? SCALE_FACTOR_DRAW : npm_b <= BishopValueMg ? 4 : 12);
+ e->factor[WHITE] = uint8_t(npm_w < RookValueMg ? SCALE_FACTOR_DRAW :
+ npm_b <= BishopValueMg ? 4 : 12);
if (!pos.count(BLACK) && npm_b - npm_w <= BishopValueMg)
- e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW : npm_w <= BishopValueMg ? 4 : 12);
+ e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW :
+ npm_w <= BishopValueMg ? 4 : 12);
if (pos.count(WHITE) == 1 && npm_w - npm_b <= BishopValueMg)
e->factor[WHITE] = (uint8_t) SCALE_FACTOR_ONEPAWN;
@@ -239,40 +211,17 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
if (pos.count(BLACK) == 1 && npm_b - npm_w <= BishopValueMg)
e->factor[BLACK] = (uint8_t) SCALE_FACTOR_ONEPAWN;
- // Compute the space weight
- if (npm_w + npm_b >= 2 * QueenValueMg + 4 * RookValueMg + 2 * KnightValueMg)
- {
- int minorPieceCount = pos.count(WHITE) + pos.count(WHITE)
- + pos.count(BLACK) + pos.count(BLACK);
-
- e->spaceWeight = make_score(minorPieceCount * minorPieceCount, 0);
- }
-
// Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder
// for the bishop pair "extended piece", which allows us to be more flexible
// in defining bishop pair bonuses.
- const int pieceCount[COLOR_NB][PIECE_TYPE_NB] = {
+ const int PieceCount[COLOR_NB][PIECE_TYPE_NB] = {
{ pos.count(WHITE) > 1, pos.count(WHITE), pos.count(WHITE),
pos.count(WHITE) , pos.count(WHITE), pos.count(WHITE) },
{ pos.count(BLACK) > 1, pos.count(BLACK), pos.count(BLACK),
pos.count(BLACK) , pos.count(BLACK), pos.count(BLACK) } };
- e->value = (int16_t)((imbalance(pieceCount) - imbalance(pieceCount)) / 16);
+ e->value = int16_t((imbalance(PieceCount) - imbalance(PieceCount)) / 16);
return e;
}
-
-/// Material::game_phase() calculates the phase given the current
-/// position. Because the phase is strictly a function of the material, it
-/// is stored in MaterialEntry.
-
-Phase game_phase(const Position& pos) {
-
- Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK);
-
- return npm >= MidgameLimit ? PHASE_MIDGAME
- : npm <= EndgameLimit ? PHASE_ENDGAME
- : Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit));
-}
-
} // namespace Material