/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2018 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <algorithm> // For std::min
#include <cassert>
-#include <cstring>
-#include <algorithm>
+#include <cstring> // 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);
-
- // Scale factors used when one side has no more pawns
- const int NoPawnsSF[4] = { 6, 12, 32 };
-
- // Polynomial material balance parameters
- const Value RedundantQueenPenalty = Value(320);
- const Value RedundantRookPenalty = Value(554);
-
- const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 };
-
- const int QuadraticCoefficientsSameColor[][8] = {
- { 7, 7, 7, 7, 7, 7 }, { 39, 2, 7, 7, 7, 7 }, { 35, 271, -4, 7, 7, 7 },
- { 7, 25, 4, 7, 7, 7 }, { -27, -2, 46, 100, 56, 7 }, { 58, 29, 83, 148, -3, -25 } };
-
- const int QuadraticCoefficientsOppositeColor[][8] = {
- { 41, 41, 41, 41, 41, 41 }, { 37, 41, 41, 41, 41, 41 }, { 10, 62, 41, 41, 41, 41 },
- { 57, 64, 39, 41, 41, 41 }, { 50, 40, 23, -22, 41, 41 }, { 106, 101, 3, 151, 171, 41 } };
-
- // Endgame evaluation and scaling functions accessed direcly and not through
- // the function maps because correspond to more then one material hash key.
- Endgame<KmmKm> EvaluateKmmKm[] = { Endgame<KmmKm>(WHITE), Endgame<KmmKm>(BLACK) };
- Endgame<KXK> EvaluateKXK[] = { Endgame<KXK>(WHITE), Endgame<KXK>(BLACK) };
+ // Polynomial material imbalance parameters
+
+ const int QuadraticOurs[][PIECE_TYPE_NB] = {
+ // OUR PIECES
+ // pair pawn knight bishop rook queen
+ {1667 }, // Bishop pair
+ { 40, 0 }, // Pawn
+ { 32, 255, -3 }, // Knight OUR PIECES
+ { 0, 104, 4, 0 }, // Bishop
+ { -26, -2, 47, 105, -149 }, // Rook
+ {-189, 24, 117, 133, -134, -10 } // Queen
+ };
+
+ const 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
+ };
+
+ // 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) };
Endgame<KBPsK> ScaleKBPsK[] = { Endgame<KBPsK>(WHITE), Endgame<KBPsK>(BLACK) };
Endgame<KQKRPs> ScaleKQKRPs[] = { Endgame<KQKRPs>(WHITE), Endgame<KQKRPs>(BLACK) };
Endgame<KPsK> ScaleKPsK[] = { Endgame<KPsK>(WHITE), Endgame<KPsK>(BLACK) };
Endgame<KPKP> ScaleKPKP[] = { Endgame<KPKP>(WHITE), Endgame<KPKP>(BLACK) };
- // Helper templates used to detect a given material distribution
- template<Color Us> bool is_KXK(const Position& pos) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- return pos.non_pawn_material(Them) == VALUE_ZERO
- && pos.piece_count(Them, PAWN) == 0
- && pos.non_pawn_material(Us) >= RookValueMidgame;
+ // 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<Color Us> bool is_KBPsKs(const Position& pos) {
- return pos.non_pawn_material(Us) == BishopValueMidgame
- && pos.piece_count(Us, BISHOP) == 1
- && pos.piece_count(Us, PAWN) >= 1;
+ bool is_KBPsK(const Position& pos, Color us) {
+ return pos.non_pawn_material(us) == BishopValueMg
+ && pos.count<BISHOP>(us) == 1
+ && pos.count<PAWN >(us) >= 1;
}
- template<Color Us> bool is_KQKRPs(const Position& pos) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- return pos.piece_count(Us, PAWN) == 0
- && pos.non_pawn_material(Us) == QueenValueMidgame
- && pos.piece_count(Us, QUEEN) == 1
- && pos.piece_count(Them, ROOK) == 1
- && pos.piece_count(Them, PAWN) >= 1;
+ 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<ROOK>(~us) == 1
+ && pos.count<PAWN>(~us) >= 1;
}
-} // namespace
+ /// 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]) {
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
-/// MaterialInfoTable c'tor and d'tor allocate and free the space for Endgames
+ int bonus = 0;
-void MaterialInfoTable::init() { Base::init(); if (!funcs) funcs = new Endgames(); }
-MaterialInfoTable::~MaterialInfoTable() { delete funcs; }
+ // Second-degree polynomial material imbalance, by Tord Romstad
+ for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
+ {
+ if (!pieceCount[Us][pt1])
+ continue;
+ int v = 0;
-/// MaterialInfoTable::get_material_info() takes a position object as input,
-/// computes or looks up a MaterialInfo object, and returns a pointer to it.
-/// If the material configuration is not already present in the table, it
-/// is stored there, so we don't have to recompute everything when the
-/// same material configuration occurs again.
+ for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
+ v += QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2]
+ + QuadraticTheirs[pt1][pt2] * pieceCount[Them][pt2];
-MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) const {
+ bonus += pieceCount[Us][pt1] * v;
+ }
- Key key = pos.get_material_key();
- MaterialInfo* mi = probe(key);
+ return bonus;
+ }
- // If mi->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 (mi->key == key)
- return mi;
+} // namespace
- // Initialize MaterialInfo entry
- memset(mi, 0, sizeof(MaterialInfo));
- mi->key = key;
- mi->factor[WHITE] = mi->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL;
+namespace Material {
- // Store game phase
- mi->gamePhase = MaterialInfoTable::game_phase(pos);
+/// 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.
- // 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.
- if ((mi->evaluationFunction = funcs->get<Value>(key)) != NULL)
- return mi;
+Entry* probe(const Position& pos) {
- if (is_KXK<WHITE>(pos))
- {
- mi->evaluationFunction = &EvaluateKXK[WHITE];
- return mi;
- }
+ Key key = pos.material_key();
+ Entry* e = pos.this_thread()->materialTable[key];
- if (is_KXK<BLACK>(pos))
- {
- mi->evaluationFunction = &EvaluateKXK[BLACK];
- return mi;
- }
+ if (e->key == key)
+ return e;
- if (!pos.pieces(PAWN) && !pos.pieces(ROOK) && !pos.pieces(QUEEN))
- {
- // Minor piece endgame with at least one minor piece per side and
- // no pawns. Note that the case KmmK is already handled by KXK.
- assert((pos.pieces(KNIGHT, WHITE) | pos.pieces(BISHOP, WHITE)));
- assert((pos.pieces(KNIGHT, BLACK) | pos.pieces(BISHOP, BLACK)));
+ std::memset(e, 0, sizeof(Entry));
+ e->key = key;
+ e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL;
+
+ 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));
+
+ // Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME]
+ e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit));
- if ( pos.piece_count(WHITE, BISHOP) + pos.piece_count(WHITE, KNIGHT) <= 2
- && pos.piece_count(BLACK, BISHOP) + pos.piece_count(BLACK, KNIGHT) <= 2)
+ // 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)
+ return e;
+
+ for (Color c = WHITE; c <= BLACK; ++c)
+ if (is_KXK(pos, c))
{
- mi->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()];
- return mi;
+ 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<ScaleFactor>* sf;
- if ((sf = funcs->get<ScaleFactor>(key)) != NULL)
+ if ((sf = pos.this_thread()->endgames.probe<ScaleFactor>(key)) != nullptr)
{
- mi->scalingFunction[sf->color()] = sf;
- return mi;
+ e->scalingFunction[sf->strongSide] = sf; // Only strong color assigned
+ return e;
}
- // Generic scaling functions that refer to more then one material
- // distribution. Should be probed after the specialized ones.
- // Note that these ones don't return after setting the function.
- if (is_KBPsKs<WHITE>(pos))
- mi->scalingFunction[WHITE] = &ScaleKBPsK[WHITE];
-
- if (is_KBPsKs<BLACK>(pos))
- mi->scalingFunction[BLACK] = &ScaleKBPsK[BLACK];
-
- if (is_KQKRPs<WHITE>(pos))
- mi->scalingFunction[WHITE] = &ScaleKQKRPs[WHITE];
-
- else if (is_KQKRPs<BLACK>(pos))
- mi->scalingFunction[BLACK] = &ScaleKQKRPs[BLACK];
+ // 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_KBPsK(pos, c))
+ e->scalingFunction[c] = &ScaleKBPsK[c];
- Value npm_w = pos.non_pawn_material(WHITE);
- Value npm_b = pos.non_pawn_material(BLACK);
+ else if (is_KQKRPs(pos, c))
+ e->scalingFunction[c] = &ScaleKQKRPs[c];
+ }
- if (npm_w + npm_b == VALUE_ZERO)
+ if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board
{
- if (pos.piece_count(BLACK, PAWN) == 0)
+ if (!pos.count<PAWN>(BLACK))
{
- assert(pos.piece_count(WHITE, PAWN) >= 2);
- mi->scalingFunction[WHITE] = &ScaleKPsK[WHITE];
+ assert(pos.count<PAWN>(WHITE) >= 2);
+
+ e->scalingFunction[WHITE] = &ScaleKPsK[WHITE];
}
- else if (pos.piece_count(WHITE, PAWN) == 0)
+ else if (!pos.count<PAWN>(WHITE))
{
- assert(pos.piece_count(BLACK, PAWN) >= 2);
- mi->scalingFunction[BLACK] = &ScaleKPsK[BLACK];
+ assert(pos.count<PAWN>(BLACK) >= 2);
+
+ e->scalingFunction[BLACK] = &ScaleKPsK[BLACK];
}
- else if (pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1)
+ else if (pos.count<PAWN>(WHITE) == 1 && pos.count<PAWN>(BLACK) == 1)
{
// This is a special case because we set scaling functions
// for both colors instead of only one.
- mi->scalingFunction[WHITE] = &ScaleKPKP[WHITE];
- mi->scalingFunction[BLACK] = &ScaleKPKP[BLACK];
+ e->scalingFunction[WHITE] = &ScaleKPKP[WHITE];
+ e->scalingFunction[BLACK] = &ScaleKPKP[BLACK];
}
}
- // No pawns makes it difficult to win, even with a material advantage
- if (pos.piece_count(WHITE, PAWN) == 0 && npm_w - npm_b <= BishopValueMidgame)
- {
- mi->factor[WHITE] = uint8_t
- (npm_w == npm_b || npm_w < RookValueMidgame ? 0 : NoPawnsSF[std::min(pos.piece_count(WHITE, BISHOP), 2)]);
- }
+ // 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<PAWN>(WHITE) && npm_w - npm_b <= BishopValueMg)
+ e->factor[WHITE] = uint8_t(npm_w < RookValueMg ? SCALE_FACTOR_DRAW :
+ npm_b <= BishopValueMg ? 4 : 14);
- if (pos.piece_count(BLACK, PAWN) == 0 && npm_b - npm_w <= BishopValueMidgame)
- {
- mi->factor[BLACK] = uint8_t
- (npm_w == npm_b || npm_b < RookValueMidgame ? 0 : NoPawnsSF[std::min(pos.piece_count(BLACK, BISHOP), 2)]);
- }
+ if (!pos.count<PAWN>(BLACK) && npm_b - npm_w <= BishopValueMg)
+ e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW :
+ npm_w <= BishopValueMg ? 4 : 14);
- // Compute the space weight
- if (npm_w + npm_b >= 2 * QueenValueMidgame + 4 * RookValueMidgame + 2 * KnightValueMidgame)
- {
- int minorPieceCount = pos.piece_count(WHITE, KNIGHT) + pos.piece_count(WHITE, BISHOP)
- + pos.piece_count(BLACK, KNIGHT) + pos.piece_count(BLACK, BISHOP);
+ if (pos.count<PAWN>(WHITE) == 1 && npm_w - npm_b <= BishopValueMg)
+ e->factor[WHITE] = (uint8_t) SCALE_FACTOR_ONEPAWN;
- mi->spaceWeight = minorPieceCount * minorPieceCount;
- }
+ if (pos.count<PAWN>(BLACK) == 1 && npm_b - npm_w <= BishopValueMg)
+ e->factor[BLACK] = (uint8_t) SCALE_FACTOR_ONEPAWN;
// Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder
- // for the bishop pair "extended piece", this allow us to be more flexible
+ // for the bishop pair "extended piece", which allows us to be more flexible
// in defining bishop pair bonuses.
- const int pieceCount[2][8] = {
- { pos.piece_count(WHITE, BISHOP) > 1, pos.piece_count(WHITE, PAWN), pos.piece_count(WHITE, KNIGHT),
- pos.piece_count(WHITE, BISHOP) , pos.piece_count(WHITE, ROOK), pos.piece_count(WHITE, QUEEN) },
- { pos.piece_count(BLACK, BISHOP) > 1, pos.piece_count(BLACK, PAWN), pos.piece_count(BLACK, KNIGHT),
- pos.piece_count(BLACK, BISHOP) , pos.piece_count(BLACK, ROOK), pos.piece_count(BLACK, QUEEN) } };
-
- mi->value = int16_t((imbalance<WHITE>(pieceCount) - imbalance<BLACK>(pieceCount)) / 16);
- return mi;
-}
-
-
-/// MaterialInfoTable::imbalance() calculates imbalance comparing piece count of each
-/// piece type for both colors.
-
-template<Color Us>
-int MaterialInfoTable::imbalance(const int pieceCount[][8]) {
-
- const Color Them = (Us == WHITE ? BLACK : WHITE);
-
- int pt1, pt2, pc, v;
- int value = 0;
-
- // Redundancy of major pieces, formula based on Kaufman's paper
- // "The Evaluation of Material Imbalances in Chess"
- if (pieceCount[Us][ROOK] > 0)
- value -= RedundantRookPenalty * (pieceCount[Us][ROOK] - 1)
- + RedundantQueenPenalty * pieceCount[Us][QUEEN];
-
- // Second-degree polynomial material imbalance by Tord Romstad
- for (pt1 = PIECE_TYPE_NONE; pt1 <= QUEEN; pt1++)
- {
- pc = pieceCount[Us][pt1];
- if (!pc)
- continue;
-
- v = LinearCoefficients[pt1];
-
- for (pt2 = PIECE_TYPE_NONE; pt2 <= pt1; pt2++)
- v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2]
- + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2];
-
- value += pc * v;
- }
- return value;
+ const int PieceCount[COLOR_NB][PIECE_TYPE_NB] = {
+ { pos.count<BISHOP>(WHITE) > 1, pos.count<PAWN>(WHITE), pos.count<KNIGHT>(WHITE),
+ pos.count<BISHOP>(WHITE) , pos.count<ROOK>(WHITE), pos.count<QUEEN >(WHITE) },
+ { pos.count<BISHOP>(BLACK) > 1, pos.count<PAWN>(BLACK), pos.count<KNIGHT>(BLACK),
+ pos.count<BISHOP>(BLACK) , pos.count<ROOK>(BLACK), pos.count<QUEEN >(BLACK) } };
+
+ e->value = int16_t((imbalance<WHITE>(PieceCount) - imbalance<BLACK>(PieceCount)) / 16);
+ return e;
}
-
-/// MaterialInfoTable::game_phase() calculates the phase given the current
-/// position. Because the phase is strictly a function of the material, it
-/// is stored in MaterialInfo.
-
-Phase MaterialInfoTable::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
projects / stockfish / blobdiff