/*
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
+ Copyright (C) 2015-2019 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 <cstring> // For std::memset
#include "material.h"
+#include "thread.h"
using namespace std;
namespace {
- // Polynomial material balance parameters
+ // Polynomial material imbalance parameters
- // pair pawn knight bishop rook queen
- const int LinearCoefficients[6] = { 1852, -162, -1122, -183, 249, -154 };
-
- const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = {
+ constexpr int QuadraticOurs[][PIECE_TYPE_NB] = {
+ // OUR PIECES
// pair pawn knight bishop rook queen
- { 0 }, // Bishop pair
- { 39, 2 }, // Pawn
- { 35, 271, -4 }, // Knight
- { 0, 105, 4, 0 }, // Bishop
- { -27, -2, 46, 100, -141 }, // Rook
- {-177, 25, 129, 142, -137, 0 } // Queen
+ {1438 }, // Bishop pair
+ { 40, 38 }, // Pawn
+ { 32, 255, -62 }, // Knight OUR PIECES
+ { 0, 104, 4, 0 }, // Bishop
+ { -26, -2, 47, 105, -208 }, // Rook
+ {-189, 24, 117, 133, -134, -6 } // Queen
};
- const int QuadraticCoefficientsOppositeColor[][PIECE_TYPE_NB] = {
+ constexpr int QuadraticTheirs[][PIECE_TYPE_NB] = {
// THEIR PIECES
// pair pawn knight bishop rook queen
{ 0 }, // Bishop pair
- { 37, 0 }, // Pawn
- { 10, 62, 0 }, // Knight OUR PIECES
- { 57, 64, 39, 0 }, // Bishop
- { 50, 40, 23, -22, 0 }, // Rook
- { 98, 105, -39, 141, 274, 0 } // Queen
+ { 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<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.count<PAWN>(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<Color Us> bool is_KBPsKs(const Position& pos) {
- return pos.non_pawn_material(Us) == BishopValueMg
- && pos.count<BISHOP>(Us) == 1
- && pos.count<PAWN >(Us) >= 1;
+ bool is_KBPsK(const Position& pos, Color us) {
+ return pos.non_pawn_material(us) == BishopValueMg
+ && pos.count<PAWN >(us) >= 1;
}
- template<Color Us> bool is_KQKRPs(const Position& pos) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- return !pos.count<PAWN>(Us)
- && pos.non_pawn_material(Us) == QueenValueMg
- && pos.count<QUEEN>(Us) == 1
- && pos.count<ROOK>(Them) == 1
- && pos.count<PAWN>(Them) >= 1;
+ bool is_KQKRPs(const Position& pos, Color us) {
+ return !pos.count<PAWN>(us)
+ && pos.non_pawn_material(us) == QueenValueMg
+ && pos.count<ROOK>(~us) == 1
+ && 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]) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr 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)
+ // Second-degree polynomial material imbalance, by Tord Romstad
+ 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 = 0;
- 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;
}
- 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);
+
+ Value npm_w = pos.non_pawn_material(WHITE);
+ Value npm_b = pos.non_pawn_material(BLACK);
+ Value npm = 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));
// 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 ((e->evaluationFunction = Endgames::probe<Value>(key)) != nullptr)
return e;
- if (is_KXK<WHITE>(pos))
- {
- e->evaluationFunction = &EvaluateKXK[WHITE];
- return e;
- }
-
- if (is_KXK<BLACK>(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.
- EndgameBase<ScaleFactor>* sf;
+ // OK, we didn't find any special evaluation function for the current material
+ // configuration. Is there a suitable specialized scaling function?
+ const auto* sf = Endgames::probe<ScaleFactor>(key);
- if (endgames.probe(key, sf))
+ if (sf)
{
- e->scalingFunction[sf->color()] = sf;
+ e->scalingFunction[sf->strongSide] = 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<WHITE>(pos))
- e->scalingFunction[WHITE] = &ScaleKBPsK[WHITE];
-
- if (is_KBPsKs<BLACK>(pos))
- e->scalingFunction[BLACK] = &ScaleKBPsK[BLACK];
-
- if (is_KQKRPs<WHITE>(pos))
- e->scalingFunction[WHITE] = &ScaleKQKRPs[WHITE];
-
- else if (is_KQKRPs<BLACK>(pos))
- e->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 && pos.pieces(PAWN))
+ if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board
{
if (!pos.count<PAWN>(BLACK))
{
assert(pos.count<PAWN>(WHITE) >= 2);
+
e->scalingFunction[WHITE] = &ScaleKPsK[WHITE];
}
else if (!pos.count<PAWN>(WHITE))
{
assert(pos.count<PAWN>(BLACK) >= 2);
+
e->scalingFunction[BLACK] = &ScaleKPsK[BLACK];
}
else if (pos.count<PAWN>(WHITE) == 1 && pos.count<PAWN>(BLACK) == 1)
}
}
- // 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<PAWN>(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 : 14);
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 : 12);
-
- if (pos.count<PAWN>(WHITE) == 1 && npm_w - npm_b <= BishopValueMg)
- e->factor[WHITE] = (uint8_t) SCALE_FACTOR_ONEPAWN;
-
- if (pos.count<PAWN>(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<KNIGHT>(WHITE) + pos.count<BISHOP>(WHITE)
- + pos.count<KNIGHT>(BLACK) + pos.count<BISHOP>(BLACK);
-
- e->spaceWeight = make_score(minorPieceCount * minorPieceCount, 0);
- }
+ e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW :
+ npm_w <= BishopValueMg ? 4 : 14);
// 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
{ 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);
+ e->value = int16_t((imbalance<WHITE>(pieceCount) - imbalance<BLACK>(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
projects / stockfish / blobdiff