/*
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
#include <algorithm>
#include <cassert>
+#include <cstring> // For std::memset
#include <iomanip>
#include <sstream>
#include "evaluate.h"
#include "material.h"
#include "pawns.h"
-#include "thread.h"
-#include "ucioption.h"
namespace {
// kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
// given color which attack a square in the kingRing of the enemy king. The
- // weights of the individual piece types are given by the variables
- // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
- // KnightAttackWeight in evaluate.cpp
+ // weights of the individual piece types are given by the elements in the
+ // KingAttackWeights array.
int kingAttackersWeight[COLOR_NB];
// kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
namespace Tracing {
- enum Terms { // First 8 entries are for PieceType
- PST = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB
+ enum Term { // First 8 entries are for PieceType
+ MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB
};
- Score terms[COLOR_NB][TERMS_NB];
- EvalInfo ei;
- ScaleFactor sf;
+ Score scores[COLOR_NB][TERMS_NB];
+
+ std::ostream& operator<<(std::ostream& os, Term idx);
double to_cp(Value v);
- void add_term(int idx, Score term_w, Score term_b = SCORE_ZERO);
- void format_row(std::stringstream& ss, const char* name, int idx);
+ void write(int idx, Color c, Score s);
+ void write(int idx, Score w, Score b = SCORE_ZERO);
std::string do_trace(const Position& pos);
}
- // Evaluation weights, initialized from UCI options
- enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
- struct Weight { int mg, eg; } Weights[6];
+ // Evaluation weights, indexed by evaluation term
+ enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety };
+ const struct Weight { int mg, eg; } Weights[] = {
+ {289, 344}, {233, 201}, {221, 273}, {46, 0}, {322, 0}
+ };
- typedef Value V;
+ #define V(v) Value(v)
#define S(mg, eg) make_score(mg, eg)
- // Internal evaluation weights. These are applied on top of the evaluation
- // weights read from UCI parameters. The purpose is to be able to change
- // the evaluation weights while keeping the default values of the UCI
- // parameters at 100, which looks prettier.
- //
- // Values modified by Joona Kiiski
- const Score WeightsInternal[] = {
- S(289, 344), S(233, 201), S(221, 273), S(46, 0), S(271, 0), S(307, 0)
- };
-
// MobilityBonus[PieceType][attacked] contains bonuses for middle and end
// game, indexed by piece type and number of attacked squares not occupied by
// friendly pieces.
S( 25, 41), S( 25, 41), S(25, 41), S(25, 41) }
};
- // Outpost[PieceType][Square] contains bonuses for knights and bishops outposts,
- // indexed by piece type and square (from white's point of view).
+ // Outpost[Bishop/Knight][Square] contains bonuses for knights and bishops
+ // outposts, indexed by piece type and square (from white's point of view).
const Value Outpost[][SQUARE_NB] = {
{// A B C D E F G H
V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
};
- // Threat[attacking][attacked] contains bonuses according to which piece
- // type attacks which one.
- const Score Threat[][PIECE_TYPE_NB] = {
- { S(0, 0), S( 7, 39), S(24, 49), S(24, 49), S(41,100), S(41,100) }, // Minor
- { S(0, 0), S(15, 39), S(15, 45), S(15, 45), S(15, 45), S(24, 49) } // Major
+ // Threat[defended/weak][minor/major attacking][attacked PieceType] contains
+ // bonuses according to which piece type attacks which one.
+ const Score Threat[][2][PIECE_TYPE_NB] = {
+ { { S(0, 0), S( 0, 0), S(19, 37), S(24, 37), S(44, 97), S(35,106) }, // Defended Minor
+ { S(0, 0), S( 0, 0), S( 9, 14), S( 9, 14), S( 7, 14), S(24, 48) } }, // Defended Major
+ { { S(0, 0), S( 0,32), S(33, 41), S(31, 50), S(41,100), S(35,104) }, // Weak Minor
+ { S(0, 0), S( 0,27), S(26, 57), S(26, 57), S(0 , 43), S(23, 51) } } // Weak Major
};
// ThreatenedByPawn[PieceType] contains a penalty according to which piece
// type is attacked by an enemy pawn.
- const Score ThreatenedByPawn[] = {
- S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
+ const Score ThreatenedByPawn[PIECE_TYPE_NB] = {
+ S(0, 0), S(0, 0), S(87, 118), S(84, 122), S(114, 203), S(121, 217)
};
- // Hanging[side to move] contains a bonus for each enemy hanging piece
- const Score Hanging[2] = { S(23, 20) , S(35, 45) };
-
- #undef S
-
- const Score Tempo = make_score(24, 11);
- const Score RookOnPawn = make_score(10, 28);
- const Score RookOpenFile = make_score(43, 21);
- const Score RookSemiopenFile = make_score(19, 10);
- const Score BishopPawns = make_score( 8, 12);
- const Score MinorBehindPawn = make_score(16, 0);
- const Score TrappedRook = make_score(90, 0);
- const Score Unstoppable = make_score( 0, 20);
+ // Assorted bonuses and penalties used by evaluation
+ const Score KingOnOne = S( 2, 58);
+ const Score KingOnMany = S( 6,125);
+ const Score RookOnPawn = S( 7, 27);
+ const Score RookOnOpenFile = S(43, 21);
+ const Score RookOnSemiOpenFile = S(19, 10);
+ const Score BishopPawns = S( 8, 12);
+ const Score MinorBehindPawn = S(16, 0);
+ const Score TrappedRook = S(92, 0);
+ const Score Unstoppable = S( 0, 20);
+ const Score Hanging = S(31, 26);
+ const Score PawnAttackThreat = S(20, 20);
// Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
// a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
// happen in Chess960 games.
- const Score TrappedBishopA1H1 = make_score(50, 50);
+ const Score TrappedBishopA1H1 = S(50, 50);
+
+ #undef S
+ #undef V
// SpaceMask[Color] contains the area of the board which is considered
// by the space evaluation. In the middlegame, each side is given a bonus
// based on how many squares inside this area are safe and available for
// friendly minor pieces.
- const Bitboard SpaceMask[] = {
+ const Bitboard SpaceMask[COLOR_NB] = {
(FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB),
(FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB)
};
- // King danger constants and variables. The king danger scores are taken
- // from KingDanger[]. Various little "meta-bonuses" measuring the strength
+ // King danger constants and variables. The king danger scores are looked-up
+ // in KingDanger[]. Various little "meta-bonuses" measuring the strength
// of the enemy attack are added up into an integer, which is used as an
// index to KingDanger[].
//
// KingAttackWeights[PieceType] contains king attack weights by piece type
- const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
+ const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 7, 5, 4, 1 };
// Bonuses for enemy's safe checks
- const int QueenContactCheck = 24;
- const int RookContactCheck = 16;
- const int QueenCheck = 12;
- const int RookCheck = 8;
- const int BishopCheck = 2;
- const int KnightCheck = 3;
-
- // KingDanger[Color][attackUnits] contains the actual king danger weighted
- // scores, indexed by color and by a calculated integer number.
- Score KingDanger[COLOR_NB][128];
-
-
- // apply_weight() weighs score 'v' by weight 'w' trying to prevent overflow
- Score apply_weight(Score v, const Weight& w) {
- return make_score(mg_value(v) * w.mg / 256, eg_value(v) * w.eg / 256);
- }
-
-
- // weight_option() computes the value of an evaluation weight, by combining
- // two UCI-configurable weights (midgame and endgame) with an internal weight.
-
- Weight weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
-
- Weight w = { Options[mgOpt] * mg_value(internalWeight) / 100,
- Options[egOpt] * eg_value(internalWeight) / 100 };
- return w;
+ const int QueenContactCheck = 89;
+ const int RookContactCheck = 71;
+ const int QueenCheck = 50;
+ const int RookCheck = 37;
+ const int BishopCheck = 6;
+ const int KnightCheck = 14;
+
+ // KingDanger[attackUnits] contains the actual king danger weighted
+ // scores, indexed by a calculated integer number.
+ Score KingDanger[512];
+
+ // apply_weight() weighs score 's' by weight 'w' trying to prevent overflow
+ Score apply_weight(Score s, const Weight& w) {
+ return make_score(mg_value(s) * w.mg / 256, eg_value(s) * w.eg / 256);
}
template<Color Us>
void init_eval_info(const Position& pos, EvalInfo& ei) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
const Square Down = (Us == WHITE ? DELTA_S : DELTA_N);
ei.pinnedPieces[Us] = pos.pinned_pieces(Us);
-
- Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
+ Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
// Init king safety tables only if we are going to use them
- if (pos.count<QUEEN>(Us) && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
+ if (pos.non_pawn_material(Us) >= QueenValueMg)
{
ei.kingRing[Them] = b | shift_bb<Down>(b);
b &= ei.attackedBy[Us][PAWN];
}
- // evaluate_outposts() evaluates bishop and knight outpost squares
+ // evaluate_outpost() evaluates bishop and knight outpost squares
template<PieceType Pt, Color Us>
- Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
+ Score evaluate_outpost(const Position& pos, const EvalInfo& ei, Square s) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
bonus += bonus / 2;
}
- return make_score(bonus, bonus);
+ return make_score(bonus * 2, bonus / 2);
}
if (Pt == BISHOP || Pt == KNIGHT)
{
- // Penalty for bishop with same colored pawns
- if (Pt == BISHOP)
- score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
-
- // Bishop and knight outposts squares
+ // Bonus for outpost square
if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
- score += evaluate_outpost
s<Pt, Us>(pos, ei, s);
+ score += evaluate_outpost<Pt, Us>(pos, ei, s);
- // Bishop or knight behind a pawn
+ // Bonus when behind a pawn
if ( relative_rank(Us, s) < RANK_5
&& (pos.pieces(PAWN) & (s + pawn_push(Us))))
score += MinorBehindPawn;
+
+ // Penalty for pawns on same color square of bishop
+ if (Pt == BISHOP)
+ score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
+
+ // An important Chess960 pattern: A cornered bishop blocked by a friendly
+ // pawn diagonally in front of it is a very serious problem, especially
+ // when that pawn is also blocked.
+ if ( Pt == BISHOP
+ && pos.is_chess960()
+ && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+ {
+ Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
+ if (pos.piece_on(s + d) == make_piece(Us, PAWN))
+ score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
+ : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
+ : TrappedBishopA1H1;
+ }
}
if (Pt == ROOK)
{
- // Rook piece attacking enemy pawns on the same rank/file
+ // Bonus for aligning with enemy pawns on the same rank/file
if (relative_rank(Us, s) >= RANK_5)
{
- Bitboard pawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
- if (pawns)
- score += popcount<Max15>(pawns) * RookOnPawn;
+ Bitboard alignedPawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
+ if (alignedPawns)
+ score += popcount<Max15>(alignedPawns) * RookOnPawn;
}
- // Give a bonus for a rook on a open or semi-open file
+ // Bonus when on an open or semi-open file
if (ei.pi->semiopen_file(Us, file_of(s)))
- score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOpenFile : RookSemiopenFile;
-
- if (mob > 3 || ei.pi->semiopen_file(Us, file_of(s)))
- continue;
-
- Square ksq = pos.king_square(Us);
+ score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOnOpenFile : RookOnSemiOpenFile;
- // Penalize rooks which are trapped by a king. Penalize more if the
- // king has lost its castling capability.
- if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
- && (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
- && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
- score -= (TrappedRook - make_score(mob * 8, 0)) * (1 + !pos.can_castle(Us));
- }
+ // Penalize when trapped by the king, even more if king cannot castle
+ if (mob <= 3 && !ei.pi->semiopen_file(Us, file_of(s)))
+ {
+ Square ksq = pos.king_square(Us);
- // An important Chess960 pattern: A cornered bishop blocked by a friendly
- // pawn diagonally in front of it is a very serious problem, especially
- // when that pawn is also blocked.
- if ( Pt == BISHOP
- && pos.is_chess960()
- && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
- {
- Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
- if (pos.piece_on(s + d) == make_piece(Us, PAWN))
- score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
- : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
- : TrappedBishopA1H1;
+ if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
+ && (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
+ && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
+ score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us));
+ }
}
}
if (Trace)
- Tracing::terms[Us][Pt] = score;
+ Tracing::write(Pt, Us, score);
+ // Recursively call evaluate_pieces() of next piece type until KING excluded
return score - evaluate_pieces<NextPt, Them, Trace>(pos, ei, mobility, mobilityArea);
}
| ei.attackedBy[Us][QUEEN]);
// Initialize the 'attackUnits' variable, which is used later on as an
- // index to the KingDanger[] array. The initial value is based on the
+ // index into the KingDanger[] array. The initial value is based on the
// number and types of the enemy's attacking pieces, the number of
// attacked and undefended squares around our king and the quality of
// the pawn shelter (current 'score' value).
- attackUnits = std::min(20, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
- + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
- + 2 * (ei.pinnedPieces[Us] != 0)
- - mg_value(score) / 32;
+ attackUnits = std::min(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
+ + 8 * ei.kingAdjacentZoneAttacksCount[Them]
+ + 25 * popcount<Max15>(undefended)
+ + 11 * (ei.pinnedPieces[Us] != 0)
+ - mg_value(score) * 31 / 256
+ - !pos.count<QUEEN>(Them) * 60;
// Analyse the enemy's safe queen contact checks. Firstly, find the
- // undefended squares around the king that are attacked by the enemy's
- // queen...
+ // undefended squares around the king reachable by the enemy queen...
b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
if (b)
{
// ...and then remove squares not supported by another enemy piece
- b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
- | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
+ b &= ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
+ | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK];
if (b)
- attackUnits += QueenContactCheck
- * popcount<Max15>(b)
- * (Them == pos.side_to_move() ? 2 : 1);
+ attackUnits += QueenContactCheck * popcount<Max15>(b);
}
// Analyse the enemy's safe rook contact checks. Firstly, find the
- // undefended squares around the king that are attacked by the enemy's
- // rooks...
+ // undefended squares around the king reachable by the enemy rooks...
b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
// Consider only squares where the enemy's rook gives check
| ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
if (b)
- attackUnits += RookContactCheck
- * popcount<Max15>(b)
- * (Them == pos.side_to_move() ? 2 : 1);
+ attackUnits += RookContactCheck * popcount<Max15>(b);
}
// Analyse the enemy's safe distance checks for sliders and knights
- safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
+ safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them));
- b1 = pos.attacks_from<ROOK>(ksq) & safe;
+ b1 = pos.attacks_from<ROOK >(ksq) & safe;
b2 = pos.attacks_from<BISHOP>(ksq) & safe;
// Enemy queen safe checks
if (b)
attackUnits += KnightCheck * popcount<Max15>(b);
- // To index KingDanger[] attackUnits must be in [0, 99] range
- attackUnits = std::min(99, std::max(0, attackUnits));
-
// Finally, extract the king danger score from the KingDanger[]
// array and subtract the score from evaluation.
- score -= KingDanger[Us == Search::RootColor][attackUnits];
+ score -= KingDanger[std::max(std::min(attackUnits, 399), 0)];
}
if (Trace)
- Tracing::terms[Us][KING] = score;
+ Tracing::write(KING, Us, score);
return score;
}
template<Color Us, bool Trace>
Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Square Up = (Us == WHITE ? DELTA_N : DELTA_S);
+ const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE);
+ const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
+ const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
+ const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+
+ enum { Defended, Weak };
+ enum { Minor, Major };
- Bitboard b, weakEnemies;
+ Bitboard b, weak, defended;
Score score = SCORE_ZERO;
+ // Non-pawn enemies defended by a pawn
+ defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN))
+ & ei.attackedBy[Them][PAWN];
+
+ // Add a bonus according to the kind of attacking pieces
+ if (defended)
+ {
+ b = defended & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+ while (b)
+ score += Threat[Defended][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
+
+ b = defended & (ei.attackedBy[Us][ROOK]);
+ while (b)
+ score += Threat[Defended][Major][type_of(pos.piece_on(pop_lsb(&b)))];
+ }
+
// Enemies not defended by a pawn and under our attack
- weakEnemies = pos.pieces(Them)
- & ~ei.attackedBy[Them][PAWN]
- & ei.attackedBy[Us][ALL_PIECES];
+ weak = pos.pieces(Them)
+ & ~ei.attackedBy[Them][PAWN]
+ & ei.attackedBy[Us][ALL_PIECES];
- // Add a bonus according if the attacking pieces are minor or major
- if (weakEnemies)
+ // Add a bonus according to the kind of attacking pieces
+ if (weak)
{
- b = weakEnemies & (ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
- if (b)
- score += Threat[0][type_of(pos.piece_on(lsb(b)))];
+ b = weak & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+ while (b)
+ score += Threat[Weak][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
- b = weakEnemies & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]);
+ b = weak & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]);
+ while (b)
+ score += Threat[Weak][Major][type_of(pos.piece_on(pop_lsb(&b)))];
+
+ b = weak & ~ei.attackedBy[Them][ALL_PIECES];
if (b)
- score += Threat[1][type_of(pos.piece_on(lsb(b)))];
+ score += Hanging * popcount<Max15>(b);
- b = weakEnemies & ~ei.attackedBy[Them][ALL_PIECES];
+ b = weak & ei.attackedBy[Us][KING];
if (b)
- score += more_than_one(b) ? Hanging[Us != pos.side_to_move()] * popcount<Max15>(b)
- : Hanging[Us == pos.side_to_move()];
+ score += more_than_one(b) ? KingOnMany : KingOnOne;
}
+ // Add bonus for safe pawn pushes which attacks an enemy piece
+ b = pos.pieces(Us, PAWN) & ~TRank7BB;
+ b = shift_bb<Up>(b | (shift_bb<Up>(b & TRank2BB) & ~pos.pieces()));
+
+ b &= ~pos.pieces()
+ & ~ei.attackedBy[Them][PAWN]
+ & (ei.attackedBy[Us][PAWN] | ~ei.attackedBy[Them][ALL_PIECES]);
+
+ b = (shift_bb<Left>(b) | shift_bb<Right>(b))
+ & pos.pieces(Them)
+ & ~ei.attackedBy[Us][PAWN];
+
+ if (b)
+ score += popcount<Max15>(b) * PawnAttackThreat;
+
if (Trace)
- Tracing::terms[Us][Tracing::THREAT] = score;
+ Tracing::write(Tracing::THREAT, Us, score);
return score;
}
Square blockSq = s + pawn_push(Us);
// Adjust bonus based on the king's proximity
- ebonus += square_distance(pos.king_square(Them), blockSq) * 5 * rr
- - square_distance(pos.king_square(Us ), blockSq) * 2 * rr;
+ ebonus += distance(pos.king_square(Them), blockSq) * 5 * rr
+ - distance(pos.king_square(Us ), blockSq) * 2 * rr;
// If blockSq is not the queening square then consider also a second push
if (relative_rank(Us, blockSq) != RANK_8)
- ebonus -= square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr;
+ ebonus -= distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr;
// If the pawn is free to advance, then increase the bonus
if (pos.empty(blockSq))
{
- squaresToQueen = forward_bb(Us, s);
-
- // If there is an enemy rook or queen attacking the pawn from behind,
- // add all X-ray attacks by the rook or queen. Otherwise consider only
- // the squares in the pawn's path attacked or occupied by the enemy.
- if ( unlikely(forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
- && (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
- unsafeSquares = squaresToQueen;
- else
- unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
-
- if ( unlikely(forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN))
- && (forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
- defendedSquares = squaresToQueen;
- else
- defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
+ // If there is a rook or queen attacking/defending the pawn from behind,
+ // consider all the squaresToQueen. Otherwise consider only the squares
+ // in the pawn's path attacked or occupied by the enemy.
+ defendedSquares = unsafeSquares = squaresToQueen = forward_bb(Us, s);
+
+ Bitboard bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
+
+ if (!(pos.pieces(Us) & bb))
+ defendedSquares &= ei.attackedBy[Us][ALL_PIECES];
+
+ if (!(pos.pieces(Them) & bb))
+ unsafeSquares &= ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them);
// If there aren't any enemy attacks, assign a big bonus. Otherwise
// assign a smaller bonus if the block square isn't attacked.
mbonus += k * rr, ebonus += k * rr;
}
+ else if (pos.pieces(Us) & blockSq)
+ mbonus += rr * 3 + r * 2 + 3, ebonus += rr + r * 2;
} // rr != 0
if (pos.count<PAWN>(Us) < pos.count<PAWN>(Them))
}
if (Trace)
- Tracing::terms[Us][Tracing::PASSED] = apply_weight(score, Weights[PassedPawns]);
+ Tracing::write(Tracing::PASSED, Us, apply_weight(score, Weights[PassedPawns]));
// Add the scores to the middlegame and endgame eval
return apply_weight(score, Weights[PassedPawns]);
}
- // evaluate_unstoppable_pawns() scores the most advanced among the passed and
- // candidate pawns. In case opponent has no pieces but pawns, this is somewhat
- // related to the possibility that pawns are unstoppable.
-
- Score evaluate_unstoppable_pawns(const Position& pos, Color us, const EvalInfo& ei) {
-
- Bitboard b = ei.pi->passed_pawns(us) | ei.pi->candidate_pawns(us);
-
- if (!b || pos.non_pawn_material(~us))
- return SCORE_ZERO;
-
- return Unstoppable * int(relative_rank(us, frontmost_sq(us, b)));
- }
-
-
// evaluate_space() computes the space evaluation for a given side. The
// space evaluation is a simple bonus based on the number of safe squares
// available for minor pieces on the central four files on ranks 2--4. Safe
// squares one, two or three squares behind a friendly pawn are counted
- // twice. Finally, the space bonus is scaled by a weight taken from the
- // material hash table. The aim is to improve play on game opening.
+ // twice. Finally, the space bonus is multiplied by a weight. The aim is to
+ // improve play on game opening.
template<Color Us>
- int evaluate_space(const Position& pos, const EvalInfo& ei) {
+ Score evaluate_space(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
// Count safe + (behind & safe) with a single popcount
- return popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
+ int bonus = popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
+ int weight = pos.count<KNIGHT>(Us) + pos.count<BISHOP>(Us)
+ + pos.count<KNIGHT>(Them) + pos.count<BISHOP>(Them);
+
+ return make_score(bonus * weight * weight, 0);
}
EvalInfo ei;
Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
- Thread* thisThread = pos.this_thread();
// Initialize score by reading the incrementally updated scores included
- // in the position object (material + piece square tables) and adding a
- // Tempo bonus. Score is computed from the point of view of white.
- score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
+ // in the position object (material + piece square tables).
+ // Score is computed from the point of view of white.
+ score = pos.psq_score();
// Probe the material hash table
- ei.mi = Material::probe(pos, thisThread->materialTable, thisThread->endgames);
- score += ei.mi->material_value();
+ ei.mi = Material::probe(pos);
+ score += ei.mi->imbalance();
// If we have a specialized evaluation function for the current material
// configuration, call it and return.
return ei.mi->evaluate(pos);
// Probe the pawn hash table
- ei.pi = Pawns::probe(pos, thisThread->pawnsTable);
- score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
+ ei.pi = Pawns::probe(pos);
+ score += apply_weight(ei.pi->pawns_score(), Weights[PawnStructure]);
// Initialize attack and king safety bitboards
init_eval_info<WHITE>(pos, ei);
score += evaluate_passed_pawns<WHITE, Trace>(pos, ei)
- evaluate_passed_pawns<BLACK, Trace>(pos, ei);
- // If one side has only a king, score for potential unstoppable pawns
- if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
- score += evaluate_unstoppable_pawns(pos, WHITE, ei)
- - evaluate_unstoppable_pawns(pos, BLACK, ei);
+ // If both sides have only pawns, score for potential unstoppable pawns
+ if (!pos.non_pawn_material(WHITE) && !pos.non_pawn_material(BLACK))
+ {
+ Bitboard b;
+ if ((b = ei.pi->passed_pawns(WHITE)) != 0)
+ score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable;
+
+ if ((b = ei.pi->passed_pawns(BLACK)) != 0)
+ score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable;
+ }
- // Evaluate space for both sides, only in middlegame
- if (ei.mi->space_weight())
+ // Evaluate space for both sides, only during opening
+ if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 2 * QueenValueMg + 4 * RookValueMg + 2 * KnightValueMg)
{
- int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
- score += apply_weight(s * ei.mi->space_weight(), Weights[Space]);
+ Score s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
+ score += apply_weight(s, Weights[Space]);
}
// Scale winning side if position is more drawish than it appears
- ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
- : ei.mi->scale_factor(pos, BLACK);
+ Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK;
+ ScaleFactor sf = ei.mi->scale_factor(pos, strongSide);
- // If we don't already have an unusual scale factor, check for opposite
- // colored bishop endgames, and use a lower scale for those.
+ // If we don't already have an unusual scale factor, check for certain
+ // types of endgames, and use a lower scale for those.
if ( ei.mi->game_phase() < PHASE_MIDGAME
- && pos.opposite_bishops()
&& (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
{
- // Ignoring any pawns, do both sides only have a single bishop and no
- // other pieces?
- if ( pos.non_pawn_material(WHITE) == BishopValueMg
- && pos.non_pawn_material(BLACK) == BishopValueMg)
+ if (pos.opposite_bishops())
{
- // Check for KBP vs KB with only a single pawn that is almost
- // certainly a draw or at least two pawns.
- bool one_pawn = (pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK) == 1);
- sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
- }
- else
+ // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
+ // is almost a draw, in case of KBP vs KB is even more a draw.
+ if ( pos.non_pawn_material(WHITE) == BishopValueMg
+ && pos.non_pawn_material(BLACK) == BishopValueMg)
+ sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(32) : ScaleFactor(8);
+
// Endgame with opposite-colored bishops, but also other pieces. Still
// a bit drawish, but not as drawish as with only the two bishops.
- sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
+ else
+ sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
+ }
+ // Endings where weaker side can place his king in front of the opponent's
+ // pawns are drawish.
+ else if ( abs(eg_value(score)) <= BishopValueEg
+ && ei.pi->pawn_span(strongSide) <= 1
+ && !pos.pawn_passed(~strongSide, pos.king_square(~strongSide)))
+ sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(56) : ScaleFactor(38);
}
// Interpolate between a middlegame and a (scaled by 'sf') endgame score
v /= int(PHASE_MIDGAME);
- // In case of tracing add all single evaluation contributions for both white and black
+ // In case of tracing add all single evaluation terms for both white and black
if (Trace)
{
- Tracing::add_term(Tracing::PST, pos.psq_score());
- Tracing::add_term(Tracing::IMBALANCE, ei.mi->material_value());
- Tracing::add_term(PAWN, ei.pi->pawns_value());
- Tracing::add_term(Tracing::MOBILITY, apply_weight(mobility[WHITE], Weights[Mobility])
- , apply_weight(mobility[BLACK], Weights[Mobility]));
- Score w = ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei);
- Score b = ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei);
- Tracing::add_term(Tracing::SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
- Tracing::add_term(Tracing::TOTAL, score);
- Tracing::ei = ei;
- Tracing::sf = sf;
+ Tracing::write(Tracing::MATERIAL, pos.psq_score());
+ Tracing::write(Tracing::IMBALANCE, ei.mi->imbalance());
+ Tracing::write(PAWN, ei.pi->pawns_score());
+ Tracing::write(Tracing::MOBILITY, apply_weight(mobility[WHITE], Weights[Mobility])
+ , apply_weight(mobility[BLACK], Weights[Mobility]));
+ Tracing::write(Tracing::SPACE, apply_weight(evaluate_space<WHITE>(pos, ei), Weights[Space])
+ , apply_weight(evaluate_space<BLACK>(pos, ei), Weights[Space]));
+ Tracing::write(Tracing::TOTAL, score);
}
- return pos.side_to_move() == WHITE ? v : -v;
+ return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo;
}
- // Tracing function definitions
+ // Tracing functions
double Tracing::to_cp(Value v) { return double(v) / PawnValueEg; }
- void Tracing::add_term(int idx, Score wScore, Score bScore) {
+ void Tracing::write(int idx, Color c, Score s) { scores[c][idx] = s; }
- terms[WHITE][idx] = wScore;
- terms[BLACK][idx] = bScore;
+ void Tracing::write(int idx, Score w, Score b) {
+ scores[WHITE][idx] = w, scores[BLACK][idx] = b;
}
- void Tracing::format_row(std::stringstream& ss, const char* name, int idx) {
-
- Score wScore = terms[WHITE][idx];
- Score bScore = terms[BLACK][idx];
-
- switch (idx) {
- case PST: case IMBALANCE: case PAWN: case TOTAL:
- ss << std::setw(20) << name << " | --- --- | --- --- | "
- << std::setw(5) << to_cp(mg_value(wScore - bScore)) << " "
- << std::setw(5) << to_cp(eg_value(wScore - bScore)) << " \n";
- break;
- default:
- ss << std::setw(20) << name << " | " << std::noshowpos
- << std::setw(5) << to_cp(mg_value(wScore)) << " "
- << std::setw(5) << to_cp(eg_value(wScore)) << " | "
- << std::setw(5) << to_cp(mg_value(bScore)) << " "
- << std::setw(5) << to_cp(eg_value(bScore)) << " | "
- << std::setw(5) << to_cp(mg_value(wScore - bScore)) << " "
- << std::setw(5) << to_cp(eg_value(wScore - bScore)) << " \n";
- }
+ std::ostream& Tracing::operator<<(std::ostream& os, Term t) {
+
+ double wScore[] = { to_cp(mg_value(scores[WHITE][t])), to_cp(eg_value(scores[WHITE][t])) };
+ double bScore[] = { to_cp(mg_value(scores[BLACK][t])), to_cp(eg_value(scores[BLACK][t])) };
+
+ if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL)
+ os << " --- --- | --- --- | ";
+ else
+ os << std::setw(5) << wScore[MG] << " " << std::setw(5) << wScore[EG] << " | "
+ << std::setw(5) << bScore[MG] << " " << std::setw(5) << bScore[EG] << " | ";
+
+ os << std::setw(5) << wScore[MG] - bScore[MG] << " "
+ << std::setw(5) << wScore[EG] - bScore[EG] << " \n";
+
+ return os;
}
std::string Tracing::do_trace(const Position& pos) {
- std::memset(terms, 0, sizeof(terms));
+ std::memset(scores, 0, sizeof(scores));
Value v = do_evaluate<true>(pos);
v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
std::stringstream ss;
ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
- << " Eval term | White | Black | Total \n"
- << " | MG EG | MG EG | MG EG \n"
- << "---------------------+-------------+-------------+-------------\n";
-
- format_row(ss, "Material, PST, Tempo", PST);
- format_row(ss, "Material imbalance", IMBALANCE);
- format_row(ss, "Pawns", PAWN);
- format_row(ss, "Knights", KNIGHT);
- format_row(ss, "Bishops", BISHOP);
- format_row(ss, "Rooks", ROOK);
- format_row(ss, "Queens", QUEEN);
- format_row(ss, "Mobility", MOBILITY);
- format_row(ss, "King safety", KING);
- format_row(ss, "Threats", THREAT);
- format_row(ss, "Passed pawns", PASSED);
- format_row(ss, "Space", SPACE);
-
- ss << "---------------------+-------------+-------------+-------------\n";
- format_row(ss, "Total", TOTAL);
+ << " Eval term | White | Black | Total \n"
+ << " | MG EG | MG EG | MG EG \n"
+ << "----------------+-------------+-------------+-------------\n"
+ << " Material | " << Term(MATERIAL)
+ << " Imbalance | " << Term(IMBALANCE)
+ << " Pawns | " << Term(PAWN)
+ << " Knights | " << Term(KNIGHT)
+ << " Bishop | " << Term(BISHOP)
+ << " Rooks | " << Term(ROOK)
+ << " Queens | " << Term(QUEEN)
+ << " Mobility | " << Term(MOBILITY)
+ << " King safety | " << Term(KING)
+ << " Threats | " << Term(THREAT)
+ << " Passed pawns | " << Term(PASSED)
+ << " Space | " << Term(SPACE)
+ << "----------------+-------------+-------------+-------------\n"
+ << " Total | " << Term(TOTAL);
ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";
}
- /// init() computes evaluation weights from the corresponding UCI parameters
- /// and setup king tables.
+ /// init() computes evaluation weights, usually at startup
void init() {
- Weights[Mobility] = weight_option("Mobility (Midgame)", "Mobility (Endgame)", WeightsInternal[Mobility]);
- Weights[PawnStructure] = weight_option("Pawn Structure (Midgame)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
- Weights[PassedPawns] = weight_option("Passed Pawns (Midgame)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
- Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
- Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
- Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
-
- const double MaxSlope = 30;
+ const double MaxSlope = 8.7;
const double Peak = 1280;
+ double t = 0.0;
- for (int t = 0, i = 1; i < 100; ++i)
+ for (int i = 1; i < 400; ++i)
{
- t = int(std::min(Peak, std::min(0.4 * i * i, t + MaxSlope)));
-
- KingDanger[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
- KingDanger[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
+ t = std::min(Peak, std::min(0.027 * i * i, t + MaxSlope));
+ KingDanger[i] = apply_weight(make_score(int(t), 0), Weights[KingSafety]);
}
}
projects / stockfish / blobdiff