mirror of
https://github.com/sockspls/badfish
synced 2025-04-29 16:23:09 +00:00

The one in evaluate_passed_pawns() is just a micro optimization, the other in evaluate_unstoppable_pawns() is indeed a fix, although almost unmeasurable in real games. Bugs report and fixes by Marek Kwiatkowski Signed-off-by: Marco Costalba <mcostalba@gmail.com>
1122 lines
43 KiB
C++
1122 lines
43 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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////
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//// Includes
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////
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#include <cassert>
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#include <cstring>
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#include "bitcount.h"
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#include "evaluate.h"
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#include "material.h"
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#include "pawns.h"
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#include "thread.h"
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#include "ucioption.h"
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////
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//// Local definitions
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////
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namespace {
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const int Sign[2] = { 1, -1 };
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// Evaluation grain size, must be a power of 2
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const int GrainSize = 8;
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// Evaluation weights, initialized from UCI options
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enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
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Score Weights[6];
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typedef Value V;
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#define S(mg, eg) make_score(mg, eg)
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// Internal evaluation weights. These are applied on top of the evaluation
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// weights read from UCI parameters. The purpose is to be able to change
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// the evaluation weights while keeping the default values of the UCI
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// parameters at 100, which looks prettier.
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//
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// Values modified by Joona Kiiski
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const Score WeightsInternal[] = {
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S(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
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};
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// Knight mobility bonus in middle game and endgame, indexed by the number
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// of attacked squares not occupied by friendly piecess.
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const Score KnightMobilityBonus[16] = {
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S(-38,-33), S(-25,-23), S(-12,-13), S( 0,-3),
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S( 12, 7), S( 25, 17), S( 31, 22), S(38, 27), S(38, 27)
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};
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// Bishop mobility bonus in middle game and endgame, indexed by the number
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// of attacked squares not occupied by friendly pieces. X-ray attacks through
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// queens are also included.
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const Score BishopMobilityBonus[16] = {
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S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12),
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S( 31, 26), S( 45, 40), S(57, 52), S(65, 60),
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S( 71, 65), S( 74, 69), S(76, 71), S(78, 73),
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S( 79, 74), S( 80, 75), S(81, 76), S(81, 76)
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};
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// Rook mobility bonus in middle game and endgame, indexed by the number
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// of attacked squares not occupied by friendly pieces. X-ray attacks through
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// queens and rooks are also included.
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const Score RookMobilityBonus[16] = {
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S(-20,-36), S(-14,-19), S(-8, -3), S(-2, 13),
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S( 4, 29), S( 10, 46), S(14, 62), S(19, 79),
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S( 23, 95), S( 26,106), S(27,111), S(28,114),
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S( 29,116), S( 30,117), S(31,118), S(32,118)
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};
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// Queen mobility bonus in middle game and endgame, indexed by the number
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// of attacked squares not occupied by friendly pieces.
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const Score QueenMobilityBonus[32] = {
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S(-10,-18), S(-8,-13), S(-6, -7), S(-3, -2), S(-1, 3), S( 1, 8),
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S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
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S( 16, 35), S(17, 35), S(18, 35), S(20, 35), S(20, 35), S(20, 35),
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S( 20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35),
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S( 20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35),
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S( 20, 35), S(20, 35)
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};
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// Pointers table to access mobility tables through piece type
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const Score* MobilityBonus[8] = { 0, 0, KnightMobilityBonus, BishopMobilityBonus,
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RookMobilityBonus, QueenMobilityBonus, 0, 0 };
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// Outpost bonuses for knights and bishops, indexed by square (from white's
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// point of view).
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const Value KnightOutpostBonus[64] = {
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// A B C D E F G H
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V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
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V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
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V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0), // 3
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V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0), // 4
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V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0), // 5
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V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0), // 6
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V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
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V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
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};
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const Value BishopOutpostBonus[64] = {
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// A B C D E F G H
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V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
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V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
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V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0), // 3
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V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0), // 4
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V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0), // 5
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V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0), // 6
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V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
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V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
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};
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// ThreatBonus[attacking][attacked] contains bonus according to which
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// piece type attacks which one.
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const Score ThreatBonus[8][8] = {
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{}, {},
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{ S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
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{ S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
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{ S(0, 0), S(-1, 29), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
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{ S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
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};
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// ThreatedByPawnPenalty[] contains a penalty according to which piece
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// type is attacked by an enemy pawn.
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const Score ThreatedByPawnPenalty[8] = {
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S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
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};
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#undef S
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// Bonus for unstoppable passed pawns
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const Value UnstoppablePawnValue = Value(0x500);
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// Rooks and queens on the 7th rank (modified by Joona Kiiski)
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const Score RookOn7thBonus = make_score(47, 98);
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const Score QueenOn7thBonus = make_score(27, 54);
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// Rooks on open files (modified by Joona Kiiski)
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const Score RookOpenFileBonus = make_score(43, 43);
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const Score RookHalfOpenFileBonus = make_score(19, 19);
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// Penalty for rooks trapped inside a friendly king which has lost the
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// right to castle.
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const Value TrappedRookPenalty = Value(180);
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// Penalty for a bishop on a7/h7 (a2/h2 for black) which is trapped by
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// enemy pawns.
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const Score TrappedBishopA7H7Penalty = make_score(300, 300);
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// Bitboard masks for detecting trapped bishops on a7/h7 (a2/h2 for black)
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const Bitboard MaskA7H7[2] = {
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((1ULL << SQ_A7) | (1ULL << SQ_H7)),
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((1ULL << SQ_A2) | (1ULL << SQ_H2))
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};
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// Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
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// a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
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// happen in Chess960 games.
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const Score TrappedBishopA1H1Penalty = make_score(100, 100);
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// Bitboard masks for detecting trapped bishops on a1/h1 (a8/h8 for black)
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const Bitboard MaskA1H1[2] = {
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((1ULL << SQ_A1) | (1ULL << SQ_H1)),
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((1ULL << SQ_A8) | (1ULL << SQ_H8))
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};
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// The SpaceMask[color] contains the area of the board which is considered
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// by the space evaluation. In the middle game, each side is given a bonus
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// based on how many squares inside this area are safe and available for
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// friendly minor pieces.
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const Bitboard SpaceMask[2] = {
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(1ULL<<SQ_C2) | (1ULL<<SQ_D2) | (1ULL<<SQ_E2) | (1ULL<<SQ_F2) |
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(1ULL<<SQ_C3) | (1ULL<<SQ_D3) | (1ULL<<SQ_E3) | (1ULL<<SQ_F3) |
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(1ULL<<SQ_C4) | (1ULL<<SQ_D4) | (1ULL<<SQ_E4) | (1ULL<<SQ_F4),
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(1ULL<<SQ_C7) | (1ULL<<SQ_D7) | (1ULL<<SQ_E7) | (1ULL<<SQ_F7) |
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(1ULL<<SQ_C6) | (1ULL<<SQ_D6) | (1ULL<<SQ_E6) | (1ULL<<SQ_F6) |
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(1ULL<<SQ_C5) | (1ULL<<SQ_D5) | (1ULL<<SQ_E5) | (1ULL<<SQ_F5)
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};
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/// King danger constants and variables. The king danger scores are taken
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/// from the KingDangerTable[]. Various little "meta-bonuses" measuring
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/// the strength of the enemy attack are added up into an integer, which
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/// is used as an index to KingDangerTable[].
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// KingAttackWeights[] contains king attack weights by piece type
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const int KingAttackWeights[8] = { 0, 0, 2, 2, 3, 5 };
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// Bonuses for enemy's safe checks
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const int QueenContactCheckBonus = 3;
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const int QueenCheckBonus = 2;
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const int RookCheckBonus = 1;
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const int BishopCheckBonus = 1;
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const int KnightCheckBonus = 1;
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// InitKingDanger[] contains bonuses based on the position of the defending
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// king.
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const int InitKingDanger[64] = {
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2, 0, 2, 5, 5, 2, 0, 2,
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2, 2, 4, 8, 8, 4, 2, 2,
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7, 10, 12, 12, 12, 12, 10, 7,
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15, 15, 15, 15, 15, 15, 15, 15,
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15, 15, 15, 15, 15, 15, 15, 15,
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15, 15, 15, 15, 15, 15, 15, 15,
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15, 15, 15, 15, 15, 15, 15, 15,
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15, 15, 15, 15, 15, 15, 15, 15
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};
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// KingDangerTable[color][] contains the actual king danger weighted scores
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Score KingDangerTable[2][128];
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// Pawn and material hash tables, indexed by the current thread id.
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// Note that they will be initialized at 0 being global variables.
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MaterialInfoTable* MaterialTable[MAX_THREADS];
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PawnInfoTable* PawnTable[MAX_THREADS];
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// Sizes of pawn and material hash tables
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const int PawnTableSize = 16384;
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const int MaterialTableSize = 1024;
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// Function prototypes
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template<bool HasPopCnt>
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Value do_evaluate(const Position& pos, EvalInfo& ei);
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template<Color Us, bool HasPopCnt>
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void init_attack_tables(const Position& pos, EvalInfo& ei);
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template<Color Us, bool HasPopCnt>
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void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei);
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template<Color Us, bool HasPopCnt>
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void evaluate_king(const Position& pos, EvalInfo& ei);
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template<Color Us>
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void evaluate_threats(const Position& pos, EvalInfo& ei);
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template<Color Us, bool HasPopCnt>
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int evaluate_space(const Position& pos, EvalInfo& ei);
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template<Color Us>
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void evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
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void evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
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void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo& ei);
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void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei);
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inline Score apply_weight(Score v, Score weight);
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Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]);
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Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
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void init_safety();
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}
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////
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//// Functions
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////
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/// evaluate() is the main evaluation function. It always computes two
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/// values, an endgame score and a middle game score, and interpolates
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/// between them based on the remaining material.
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Value evaluate(const Position& pos, EvalInfo& ei) {
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return CpuHasPOPCNT ? do_evaluate<true>(pos, ei)
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: do_evaluate<false>(pos, ei);
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}
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namespace {
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template<bool HasPopCnt>
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Value do_evaluate(const Position& pos, EvalInfo& ei) {
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ScaleFactor factor[2];
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assert(pos.is_ok());
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assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
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assert(!pos.is_check());
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memset(&ei, 0, sizeof(EvalInfo));
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// Initialize by reading the incrementally updated scores included in the
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// position object (material + piece square tables)
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ei.value = pos.value();
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// Probe the material hash table
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ei.mi = MaterialTable[pos.thread()]->get_material_info(pos);
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ei.value += ei.mi->material_value();
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// If we have a specialized evaluation function for the current material
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// configuration, call it and return
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if (ei.mi->specialized_eval_exists())
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return ei.mi->evaluate(pos);
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// After get_material_info() call that modifies them
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factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
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factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
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// Probe the pawn hash table
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ei.pi = PawnTable[pos.thread()]->get_pawn_info(pos);
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ei.value += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
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// Initialize attack bitboards with pawns evaluation
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init_attack_tables<WHITE, HasPopCnt>(pos, ei);
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init_attack_tables<BLACK, HasPopCnt>(pos, ei);
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// Evaluate pieces
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evaluate_pieces_of_color<WHITE, HasPopCnt>(pos, ei);
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evaluate_pieces_of_color<BLACK, HasPopCnt>(pos, ei);
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// Kings. Kings are evaluated after all other pieces for both sides,
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// because we need complete attack information for all pieces when computing
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// the king safety evaluation.
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evaluate_king<WHITE, HasPopCnt>(pos, ei);
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evaluate_king<BLACK, HasPopCnt>(pos, ei);
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// Evaluate tactical threats, we need full attack info including king
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evaluate_threats<WHITE>(pos, ei);
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evaluate_threats<BLACK>(pos, ei);
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// Evaluate passed pawns, we need full attack info including king
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evaluate_passed_pawns<WHITE>(pos, ei);
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evaluate_passed_pawns<BLACK>(pos, ei);
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// If one side has only a king, check whether exsists any unstoppable passed pawn
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if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
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evaluate_unstoppable_pawns(pos, ei);
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Phase phase = ei.mi->game_phase();
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// Middle-game specific evaluation terms
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if (phase > PHASE_ENDGAME)
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{
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// Pawn storms in positions with opposite castling
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if ( square_file(pos.king_square(WHITE)) >= FILE_E
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&& square_file(pos.king_square(BLACK)) <= FILE_D)
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ei.value += make_score(ei.pi->queenside_storm_value(WHITE) - ei.pi->kingside_storm_value(BLACK), 0);
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else if ( square_file(pos.king_square(WHITE)) <= FILE_D
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&& square_file(pos.king_square(BLACK)) >= FILE_E)
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ei.value += make_score(ei.pi->kingside_storm_value(WHITE) - ei.pi->queenside_storm_value(BLACK), 0);
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// Evaluate space for both sides
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if (ei.mi->space_weight() > 0)
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{
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int s = evaluate_space<WHITE, HasPopCnt>(pos, ei) - evaluate_space<BLACK, HasPopCnt>(pos, ei);
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ei.value += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
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}
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}
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// Mobility
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ei.value += apply_weight(ei.mobility, Weights[Mobility]);
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// If we don't already have an unusual scale factor, check for opposite
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// colored bishop endgames, and use a lower scale for those
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if ( phase < PHASE_MIDGAME
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&& pos.opposite_colored_bishops()
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&& ( (factor[WHITE] == SCALE_FACTOR_NORMAL && eg_value(ei.value) > Value(0))
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|| (factor[BLACK] == SCALE_FACTOR_NORMAL && eg_value(ei.value) < Value(0))))
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{
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ScaleFactor sf;
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// Only the two bishops ?
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if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
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&& pos.non_pawn_material(BLACK) == BishopValueMidgame)
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{
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// Check for KBP vs KB with only a single pawn that is almost
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// certainly a draw or at least two pawns.
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bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
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sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
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}
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else
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// Endgame with opposite-colored bishops, but also other pieces. Still
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// a bit drawish, but not as drawish as with only the two bishops.
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sf = ScaleFactor(50);
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if (factor[WHITE] == SCALE_FACTOR_NORMAL)
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factor[WHITE] = sf;
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if (factor[BLACK] == SCALE_FACTOR_NORMAL)
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factor[BLACK] = sf;
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}
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// Interpolate between the middle game and the endgame score
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return Sign[pos.side_to_move()] * scale_by_game_phase(ei.value, phase, factor);
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}
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} // namespace
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/// init_eval() initializes various tables used by the evaluation function
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void init_eval(int threads) {
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|
|
assert(threads <= MAX_THREADS);
|
|
|
|
for (int i = 0; i < MAX_THREADS; i++)
|
|
{
|
|
if (i >= threads)
|
|
{
|
|
delete PawnTable[i];
|
|
delete MaterialTable[i];
|
|
PawnTable[i] = NULL;
|
|
MaterialTable[i] = NULL;
|
|
continue;
|
|
}
|
|
if (!PawnTable[i])
|
|
PawnTable[i] = new PawnInfoTable(PawnTableSize);
|
|
if (!MaterialTable[i])
|
|
MaterialTable[i] = new MaterialInfoTable(MaterialTableSize);
|
|
}
|
|
}
|
|
|
|
|
|
/// quit_eval() releases heap-allocated memory at program termination
|
|
|
|
void quit_eval() {
|
|
|
|
for (int i = 0; i < MAX_THREADS; i++)
|
|
{
|
|
delete PawnTable[i];
|
|
delete MaterialTable[i];
|
|
PawnTable[i] = NULL;
|
|
MaterialTable[i] = NULL;
|
|
}
|
|
}
|
|
|
|
|
|
/// read_weights() reads evaluation weights from the corresponding UCI parameters
|
|
|
|
void read_weights(Color us) {
|
|
|
|
// King safety is asymmetrical. Our king danger level is weighted by
|
|
// "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
|
|
const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
|
|
const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
|
|
|
|
Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
|
|
Weights[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
|
|
Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "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]);
|
|
|
|
// If running in analysis mode, make sure we use symmetrical king safety. We do this
|
|
// by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
|
|
if (get_option_value_bool("UCI_AnalyseMode"))
|
|
Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
|
|
|
|
init_safety();
|
|
}
|
|
|
|
|
|
namespace {
|
|
|
|
// init_attack_tables() initializes king bitboards for both sides adding
|
|
// pawn attacks. To be done before other evaluations.
|
|
|
|
template<Color Us, bool HasPopCnt>
|
|
void init_attack_tables(const Position& pos, EvalInfo& ei) {
|
|
|
|
const Color Them = (Us == WHITE ? BLACK : WHITE);
|
|
|
|
Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
|
|
ei.kingZone[Us] = (b | (Us == WHITE ? b >> 8 : b << 8));
|
|
ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
|
|
b &= ei.attackedBy[Us][PAWN];
|
|
if (b)
|
|
ei.kingAttackersCount[Us] = count_1s_max_15<HasPopCnt>(b) / 2;
|
|
}
|
|
|
|
|
|
// evaluate_outposts() evaluates bishop and knight outposts squares
|
|
|
|
template<PieceType Piece, Color Us>
|
|
void evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
|
|
|
|
const Color Them = (Us == WHITE ? BLACK : WHITE);
|
|
|
|
// Initial bonus based on square
|
|
Value bonus = (Piece == BISHOP ? BishopOutpostBonus[relative_square(Us, s)]
|
|
: KnightOutpostBonus[relative_square(Us, s)]);
|
|
|
|
// Increase bonus if supported by pawn, especially if the opponent has
|
|
// no minor piece which can exchange the outpost piece
|
|
if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
|
|
{
|
|
if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
|
|
&& (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
|
|
bonus += bonus + bonus / 2;
|
|
else
|
|
bonus += bonus / 2;
|
|
}
|
|
ei.value += Sign[Us] * make_score(bonus, bonus);
|
|
}
|
|
|
|
|
|
// evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
|
|
|
|
template<PieceType Piece, Color Us, bool HasPopCnt>
|
|
void evaluate_pieces(const Position& pos, EvalInfo& ei, Bitboard no_mob_area) {
|
|
|
|
Bitboard b;
|
|
Square s, ksq;
|
|
int mob;
|
|
File f;
|
|
|
|
const Color Them = (Us == WHITE ? BLACK : WHITE);
|
|
const Square* ptr = pos.piece_list_begin(Us, Piece);
|
|
|
|
while ((s = *ptr++) != SQ_NONE)
|
|
{
|
|
// Find attacked squares, including x-ray attacks for bishops and rooks
|
|
if (Piece == KNIGHT || Piece == QUEEN)
|
|
b = pos.attacks_from<Piece>(s);
|
|
else if (Piece == BISHOP)
|
|
b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
|
|
else if (Piece == ROOK)
|
|
b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
|
|
else
|
|
assert(false);
|
|
|
|
// Update attack info
|
|
ei.attackedBy[Us][Piece] |= b;
|
|
|
|
// King attacks
|
|
if (b & ei.kingZone[Us])
|
|
{
|
|
ei.kingAttackersCount[Us]++;
|
|
ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
|
|
Bitboard bb = (b & ei.attackedBy[Them][KING]);
|
|
if (bb)
|
|
ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(bb);
|
|
}
|
|
|
|
// Mobility
|
|
mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(b & no_mob_area)
|
|
: count_1s<HasPopCnt>(b & no_mob_area));
|
|
|
|
ei.mobility += Sign[Us] * MobilityBonus[Piece][mob];
|
|
|
|
// Decrease score if we are attacked by an enemy pawn. Remaining part
|
|
// of threat evaluation must be done later when we have full attack info.
|
|
if (bit_is_set(ei.attackedBy[Them][PAWN], s))
|
|
ei.value -= Sign[Us] * ThreatedByPawnPenalty[Piece];
|
|
|
|
// Bishop and knight outposts squares
|
|
if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Us))
|
|
evaluate_outposts<Piece, Us>(pos, ei, s);
|
|
|
|
// Special patterns: trapped bishops on a7/h7/a2/h2
|
|
// and trapped bishops on a1/h1/a8/h8 in Chess960.
|
|
if (Piece == BISHOP)
|
|
{
|
|
if (bit_is_set(MaskA7H7[Us], s))
|
|
evaluate_trapped_bishop_a7h7(pos, s, Us, ei);
|
|
|
|
if (Chess960 && bit_is_set(MaskA1H1[Us], s))
|
|
evaluate_trapped_bishop_a1h1(pos, s, Us, ei);
|
|
}
|
|
|
|
// Queen or rook on 7th rank
|
|
if ( (Piece == ROOK || Piece == QUEEN)
|
|
&& relative_rank(Us, s) == RANK_7
|
|
&& relative_rank(Us, pos.king_square(Them)) == RANK_8)
|
|
{
|
|
ei.value += Sign[Us] * (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
|
|
}
|
|
|
|
// Special extra evaluation for rooks
|
|
if (Piece == ROOK)
|
|
{
|
|
// Open and half-open files
|
|
f = square_file(s);
|
|
if (ei.pi->file_is_half_open(Us, f))
|
|
{
|
|
if (ei.pi->file_is_half_open(Them, f))
|
|
ei.value += Sign[Us] * RookOpenFileBonus;
|
|
else
|
|
ei.value += Sign[Us] * RookHalfOpenFileBonus;
|
|
}
|
|
|
|
// Penalize rooks which are trapped inside a king. Penalize more if
|
|
// king has lost right to castle.
|
|
if (mob > 6 || ei.pi->file_is_half_open(Us, f))
|
|
continue;
|
|
|
|
ksq = pos.king_square(Us);
|
|
|
|
if ( square_file(ksq) >= FILE_E
|
|
&& square_file(s) > square_file(ksq)
|
|
&& (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
|
|
{
|
|
// Is there a half-open file between the king and the edge of the board?
|
|
if (!ei.pi->has_open_file_to_right(Us, square_file(ksq)))
|
|
ei.value -= Sign[Us] * make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
|
|
: (TrappedRookPenalty - mob * 16), 0);
|
|
}
|
|
else if ( square_file(ksq) <= FILE_D
|
|
&& square_file(s) < square_file(ksq)
|
|
&& (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
|
|
{
|
|
// Is there a half-open file between the king and the edge of the board?
|
|
if (!ei.pi->has_open_file_to_left(Us, square_file(ksq)))
|
|
ei.value -= Sign[Us] * make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
|
|
: (TrappedRookPenalty - mob * 16), 0);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
// evaluate_threats<>() assigns bonuses according to the type of attacking piece
|
|
// and the type of attacked one.
|
|
|
|
template<Color Us>
|
|
void evaluate_threats(const Position& pos, EvalInfo& ei) {
|
|
|
|
const Color Them = (Us == WHITE ? BLACK : WHITE);
|
|
|
|
Bitboard b;
|
|
Score bonus = make_score(0, 0);
|
|
|
|
// Enemy pieces not defended by a pawn and under our attack
|
|
Bitboard weakEnemies = pos.pieces_of_color(Them)
|
|
& ~ei.attackedBy[Them][PAWN]
|
|
& ei.attackedBy[Us][0];
|
|
if (!weakEnemies)
|
|
return;
|
|
|
|
// Add bonus according to type of attacked enemy pieces and to the
|
|
// type of attacking piece, from knights to queens. Kings are not
|
|
// considered because are already special handled in king evaluation.
|
|
for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
|
|
{
|
|
b = ei.attackedBy[Us][pt1] & weakEnemies;
|
|
if (b)
|
|
for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
|
|
if (b & pos.pieces(pt2))
|
|
bonus += ThreatBonus[pt1][pt2];
|
|
}
|
|
ei.value += Sign[Us] * bonus;
|
|
}
|
|
|
|
|
|
// evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
|
|
// pieces of a given color.
|
|
|
|
template<Color Us, bool HasPopCnt>
|
|
void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei) {
|
|
|
|
const Color Them = (Us == WHITE ? BLACK : WHITE);
|
|
|
|
// Do not include in mobility squares protected by enemy pawns or occupied by our pieces
|
|
const Bitboard no_mob_area = ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
|
|
|
|
evaluate_pieces<KNIGHT, Us, HasPopCnt>(pos, ei, no_mob_area);
|
|
evaluate_pieces<BISHOP, Us, HasPopCnt>(pos, ei, no_mob_area);
|
|
evaluate_pieces<ROOK, Us, HasPopCnt>(pos, ei, no_mob_area);
|
|
evaluate_pieces<QUEEN, Us, HasPopCnt>(pos, ei, no_mob_area);
|
|
|
|
// Sum up all attacked squares
|
|
ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
|
|
| ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
|
|
| ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
|
|
}
|
|
|
|
|
|
// evaluate_king<>() assigns bonuses and penalties to a king of a given color
|
|
|
|
template<Color Us, bool HasPopCnt>
|
|
void evaluate_king(const Position& pos, EvalInfo& ei) {
|
|
|
|
const Color Them = (Us == WHITE ? BLACK : WHITE);
|
|
|
|
Bitboard undefended, b, b1, b2, safe;
|
|
bool sente;
|
|
int attackUnits, shelter = 0;
|
|
const Square ksq = pos.king_square(Us);
|
|
|
|
// King shelter
|
|
if (relative_rank(Us, ksq) <= RANK_4)
|
|
{
|
|
shelter = ei.pi->get_king_shelter(pos, Us, ksq);
|
|
ei.value += Sign[Us] * make_score(shelter, 0);
|
|
}
|
|
|
|
// King safety. This is quite complicated, and is almost certainly far
|
|
// from optimally tuned.
|
|
if ( pos.piece_count(Them, QUEEN) >= 1
|
|
&& ei.kingAttackersCount[Them] >= 2
|
|
&& pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame
|
|
&& ei.kingAdjacentZoneAttacksCount[Them])
|
|
{
|
|
// Is it the attackers turn to move?
|
|
sente = (Them == pos.side_to_move());
|
|
|
|
// Find the attacked squares around the king which has no defenders
|
|
// apart from the king itself
|
|
undefended = ei.attacked_by(Them) & ei.attacked_by(Us, KING);
|
|
undefended &= ~( ei.attacked_by(Us, PAWN) | ei.attacked_by(Us, KNIGHT)
|
|
| ei.attacked_by(Us, BISHOP) | ei.attacked_by(Us, ROOK)
|
|
| ei.attacked_by(Us, QUEEN));
|
|
|
|
// Initialize the 'attackUnits' variable, which is used later on as an
|
|
// index to the KingDangerTable[] 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, the square of the
|
|
// king, and the quality of the pawn shelter.
|
|
attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
|
|
+ 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended))
|
|
+ InitKingDanger[relative_square(Us, ksq)]
|
|
- shelter / 32;
|
|
|
|
// Analyse enemy's safe queen contact checks. First find undefended
|
|
// squares around the king attacked by enemy queen...
|
|
b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.pieces_of_color(Them);
|
|
if (b)
|
|
{
|
|
// ...then remove squares not supported by another enemy piece
|
|
b &= ( ei.attacked_by(Them, PAWN) | ei.attacked_by(Them, KNIGHT)
|
|
| ei.attacked_by(Them, BISHOP) | ei.attacked_by(Them, ROOK));
|
|
if (b)
|
|
attackUnits += QueenContactCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
|
|
}
|
|
|
|
// Analyse enemy's safe distance checks for sliders and knights
|
|
safe = ~(pos.pieces_of_color(Them) | ei.attacked_by(Us));
|
|
|
|
b1 = pos.attacks_from<ROOK>(ksq) & safe;
|
|
b2 = pos.attacks_from<BISHOP>(ksq) & safe;
|
|
|
|
// Enemy queen safe checks
|
|
b = (b1 | b2) & ei.attacked_by(Them, QUEEN);
|
|
if (b)
|
|
attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b);
|
|
|
|
// Enemy rooks safe checks
|
|
b = b1 & ei.attacked_by(Them, ROOK);
|
|
if (b)
|
|
attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b);
|
|
|
|
// Enemy bishops safe checks
|
|
b = b2 & ei.attacked_by(Them, BISHOP);
|
|
if (b)
|
|
attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b);
|
|
|
|
// Enemy knights safe checks
|
|
b = pos.attacks_from<KNIGHT>(ksq) & ei.attacked_by(Them, KNIGHT) & safe;
|
|
if (b)
|
|
attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b);
|
|
|
|
// To index KingDangerTable[] attackUnits must be in [0, 99] range
|
|
attackUnits = Min(99, Max(0, attackUnits));
|
|
|
|
// Finally, extract the king danger score from the KingDangerTable[]
|
|
// array and subtract the score from evaluation. Set also ei.kingDanger[]
|
|
// value that will be used for pruning because this value can sometimes
|
|
// be very big, and so capturing a single attacking piece can therefore
|
|
// result in a score change far bigger than the value of the captured piece.
|
|
ei.value -= Sign[Us] * KingDangerTable[Us][attackUnits];
|
|
ei.kingDanger[Us] = mg_value(KingDangerTable[Us][attackUnits]);
|
|
}
|
|
}
|
|
|
|
|
|
// evaluate_passed_pawns<>() evaluates the passed pawns of the given color
|
|
|
|
template<Color Us>
|
|
void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
|
|
|
|
const Color Them = (Us == WHITE ? BLACK : WHITE);
|
|
|
|
Bitboard squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
|
|
Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(Us);
|
|
|
|
while (b)
|
|
{
|
|
Square s = pop_1st_bit(&b);
|
|
|
|
assert(pos.pawn_is_passed(Us, s));
|
|
|
|
int r = int(relative_rank(Us, s) - RANK_2);
|
|
int tr = r * (r - 1);
|
|
|
|
// Base bonus based on rank
|
|
Value mbonus = Value(20 * tr);
|
|
Value ebonus = Value(10 + r * r * 10);
|
|
|
|
if (tr)
|
|
{
|
|
Square blockSq = s + pawn_push(Us);
|
|
|
|
// Adjust bonus based on kings proximity
|
|
ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * tr);
|
|
ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * 1 * tr);
|
|
ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * tr);
|
|
|
|
// If the pawn is free to advance, increase bonus
|
|
if (pos.square_is_empty(blockSq))
|
|
{
|
|
squaresToQueen = squares_in_front_of(Us, s);
|
|
defendedSquares = squaresToQueen & ei.attacked_by(Us);
|
|
|
|
// 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 ( (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them))
|
|
&& (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<ROOK>(s)))
|
|
unsafeSquares = squaresToQueen;
|
|
else
|
|
unsafeSquares = squaresToQueen & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
|
|
|
|
// If there aren't enemy attacks or pieces along the path to queen give
|
|
// huge bonus. Even bigger if we protect the pawn's path.
|
|
if (!unsafeSquares)
|
|
ebonus += Value(tr * (squaresToQueen == defendedSquares ? 17 : 15));
|
|
else
|
|
// OK, there are enemy attacks or pieces (but not pawns). Are those
|
|
// squares which are attacked by the enemy also attacked by us ?
|
|
// If yes, big bonus (but smaller than when there are no enemy attacks),
|
|
// if no, somewhat smaller bonus.
|
|
ebonus += Value(tr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
|
|
|
|
// At last, add a small bonus when there are no *friendly* pieces
|
|
// in the pawn's path.
|
|
if (!(squaresToQueen & pos.pieces_of_color(Us)))
|
|
ebonus += Value(tr);
|
|
}
|
|
} // tr != 0
|
|
|
|
// Increase the bonus if the passed pawn is supported by a friendly pawn
|
|
// on the same rank and a bit smaller if it's on the previous rank.
|
|
supportingPawns = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
|
|
if (supportingPawns & rank_bb(s))
|
|
ebonus += Value(r * 20);
|
|
else if (supportingPawns & rank_bb(s - pawn_push(Us)))
|
|
ebonus += Value(r * 12);
|
|
|
|
// Rook pawns are a special case: They are sometimes worse, and
|
|
// sometimes better than other passed pawns. It is difficult to find
|
|
// good rules for determining whether they are good or bad. For now,
|
|
// we try the following: Increase the value for rook pawns if the
|
|
// other side has no pieces apart from a knight, and decrease the
|
|
// value if the other side has a rook or queen.
|
|
if (square_file(s) == FILE_A || square_file(s) == FILE_H)
|
|
{
|
|
if (pos.non_pawn_material(Them) <= KnightValueMidgame)
|
|
ebonus += ebonus / 4;
|
|
else if (pos.pieces(ROOK, QUEEN, Them))
|
|
ebonus -= ebonus / 4;
|
|
}
|
|
|
|
// Add the scores for this pawn to the middle game and endgame eval
|
|
ei.value += Sign[Us] * apply_weight(make_score(mbonus, ebonus), Weights[PassedPawns]);
|
|
|
|
} // while
|
|
}
|
|
|
|
|
|
// evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides
|
|
|
|
void evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
|
|
|
|
int movesToGo[2] = {0, 0};
|
|
Square pawnToGo[2] = {SQ_NONE, SQ_NONE};
|
|
|
|
for (Color c = WHITE; c <= BLACK; c++)
|
|
{
|
|
// Skip evaluation if other side has non-pawn pieces
|
|
if (pos.non_pawn_material(opposite_color(c)))
|
|
continue;
|
|
|
|
Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(c);
|
|
|
|
while (b)
|
|
{
|
|
Square s = pop_1st_bit(&b);
|
|
Square queeningSquare = relative_square(c, make_square(square_file(s), RANK_8));
|
|
int d = square_distance(s, queeningSquare)
|
|
- int(relative_rank(c, s) == RANK_2) // Double pawn push
|
|
- square_distance(pos.king_square(opposite_color(c)), queeningSquare)
|
|
+ int(c != pos.side_to_move());
|
|
|
|
// Do we protect the path to queening ?
|
|
bool pathDefended = (ei.attacked_by(c) & squares_in_front_of(c, s)) == squares_in_front_of(c, s);
|
|
|
|
if (d < 0 || pathDefended)
|
|
{
|
|
int mtg = RANK_8 - relative_rank(c, s) - int(relative_rank(c, s) == RANK_2);
|
|
int blockerCount = count_1s_max_15(squares_in_front_of(c, s) & pos.occupied_squares());
|
|
mtg += blockerCount;
|
|
d += blockerCount;
|
|
if ((d < 0 || pathDefended) && (!movesToGo[c] || movesToGo[c] > mtg))
|
|
{
|
|
movesToGo[c] = mtg;
|
|
pawnToGo[c] = s;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Neither side has an unstoppable passed pawn?
|
|
if (!(movesToGo[WHITE] | movesToGo[BLACK]))
|
|
return;
|
|
|
|
// Does only one side have an unstoppable passed pawn?
|
|
if (!movesToGo[WHITE] || !movesToGo[BLACK])
|
|
{
|
|
Color winnerSide = movesToGo[WHITE] ? WHITE : BLACK;
|
|
ei.value += make_score(0, Sign[winnerSide] * (UnstoppablePawnValue - Value(0x40 * movesToGo[winnerSide])));
|
|
}
|
|
else
|
|
{ // Both sides have unstoppable pawns! Try to find out who queens
|
|
// first. We begin by transforming 'movesToGo' to the number of
|
|
// plies until the pawn queens for both sides.
|
|
movesToGo[WHITE] *= 2;
|
|
movesToGo[BLACK] *= 2;
|
|
movesToGo[pos.side_to_move()]--;
|
|
|
|
Color winnerSide = movesToGo[WHITE] < movesToGo[BLACK] ? WHITE : BLACK;
|
|
Color loserSide = opposite_color(winnerSide);
|
|
|
|
// If one side queens at least three plies before the other, that side wins
|
|
if (movesToGo[winnerSide] <= movesToGo[loserSide] - 3)
|
|
ei.value += Sign[winnerSide] * make_score(0, UnstoppablePawnValue - Value(0x40 * (movesToGo[winnerSide]/2)));
|
|
|
|
// If one side queens one ply before the other and checks the king or attacks
|
|
// the undefended opponent's queening square, that side wins. To avoid cases
|
|
// where the opponent's king could move somewhere before first pawn queens we
|
|
// consider only free paths to queen for both pawns.
|
|
else if ( !(squares_in_front_of(WHITE, pawnToGo[WHITE]) & pos.occupied_squares())
|
|
&& !(squares_in_front_of(BLACK, pawnToGo[BLACK]) & pos.occupied_squares()))
|
|
{
|
|
assert(movesToGo[loserSide] - movesToGo[winnerSide] == 1);
|
|
|
|
Square winnerQSq = relative_square(winnerSide, make_square(square_file(pawnToGo[winnerSide]), RANK_8));
|
|
Square loserQSq = relative_square(loserSide, make_square(square_file(pawnToGo[loserSide]), RANK_8));
|
|
|
|
Bitboard b = pos.occupied_squares();
|
|
clear_bit(&b, pawnToGo[winnerSide]);
|
|
clear_bit(&b, pawnToGo[loserSide]);
|
|
b = queen_attacks_bb(winnerQSq, b);
|
|
|
|
if ( (b & pos.pieces(KING, loserSide))
|
|
||(bit_is_set(b, loserQSq) && !bit_is_set(ei.attacked_by(loserSide), loserQSq)))
|
|
ei.value += Sign[winnerSide] * make_score(0, UnstoppablePawnValue - Value(0x40 * (movesToGo[winnerSide]/2)));
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
// evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7
|
|
// (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty
|
|
// if it is.
|
|
|
|
void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo &ei) {
|
|
|
|
assert(square_is_ok(s));
|
|
assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
|
|
|
|
Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6);
|
|
Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8);
|
|
|
|
if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN)
|
|
&& pos.see(s, b6) < 0
|
|
&& pos.see(s, b8) < 0)
|
|
{
|
|
ei.value -= Sign[us] * TrappedBishopA7H7Penalty;
|
|
}
|
|
}
|
|
|
|
|
|
// evaluate_trapped_bishop_a1h1() determines whether a bishop on a1/h1
|
|
// (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for
|
|
// black), and assigns a penalty if it is. This pattern can obviously
|
|
// only occur in Chess960 games.
|
|
|
|
void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei) {
|
|
|
|
Piece pawn = piece_of_color_and_type(us, PAWN);
|
|
Square b2, b3, c3;
|
|
|
|
assert(Chess960);
|
|
assert(square_is_ok(s));
|
|
assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
|
|
|
|
if (square_file(s) == FILE_A)
|
|
{
|
|
b2 = relative_square(us, SQ_B2);
|
|
b3 = relative_square(us, SQ_B3);
|
|
c3 = relative_square(us, SQ_C3);
|
|
}
|
|
else
|
|
{
|
|
b2 = relative_square(us, SQ_G2);
|
|
b3 = relative_square(us, SQ_G3);
|
|
c3 = relative_square(us, SQ_F3);
|
|
}
|
|
|
|
if (pos.piece_on(b2) == pawn)
|
|
{
|
|
Score penalty;
|
|
|
|
if (!pos.square_is_empty(b3))
|
|
penalty = 2 * TrappedBishopA1H1Penalty;
|
|
else if (pos.piece_on(c3) == pawn)
|
|
penalty = TrappedBishopA1H1Penalty;
|
|
else
|
|
penalty = TrappedBishopA1H1Penalty / 2;
|
|
|
|
ei.value -= Sign[us] * penalty;
|
|
}
|
|
}
|
|
|
|
|
|
// 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.
|
|
template<Color Us, bool HasPopCnt>
|
|
int evaluate_space(const Position& pos, EvalInfo& ei) {
|
|
|
|
const Color Them = (Us == WHITE ? BLACK : WHITE);
|
|
|
|
// Find the safe squares for our pieces inside the area defined by
|
|
// SpaceMask[us]. A square is unsafe if it is attacked by an enemy
|
|
// pawn, or if it is undefended and attacked by an enemy piece.
|
|
Bitboard safe = SpaceMask[Us]
|
|
& ~pos.pieces(PAWN, Us)
|
|
& ~ei.attacked_by(Them, PAWN)
|
|
& (ei.attacked_by(Us) | ~ei.attacked_by(Them));
|
|
|
|
// Find all squares which are at most three squares behind some friendly pawn
|
|
Bitboard behind = pos.pieces(PAWN, Us);
|
|
behind |= (Us == WHITE ? behind >> 8 : behind << 8);
|
|
behind |= (Us == WHITE ? behind >> 16 : behind << 16);
|
|
|
|
return count_1s_max_15<HasPopCnt>(safe) + count_1s_max_15<HasPopCnt>(behind & safe);
|
|
}
|
|
|
|
|
|
// apply_weight() applies an evaluation weight to a value trying to prevent overflow
|
|
|
|
inline Score apply_weight(Score v, Score w) {
|
|
return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, (int(eg_value(v)) * eg_value(w)) / 0x100);
|
|
}
|
|
|
|
|
|
// scale_by_game_phase() interpolates between a middle game and an endgame score,
|
|
// based on game phase. It also scales the return value by a ScaleFactor array.
|
|
|
|
Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]) {
|
|
|
|
assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
|
|
assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
|
|
assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
|
|
|
|
Value eg = eg_value(v);
|
|
ScaleFactor f = sf[eg > Value(0) ? WHITE : BLACK];
|
|
Value ev = Value((eg * f) / SCALE_FACTOR_NORMAL);
|
|
|
|
int result = (mg_value(v) * ph + ev * (128 - ph)) / 128;
|
|
return Value(result & ~(GrainSize - 1));
|
|
}
|
|
|
|
|
|
// weight_option() computes the value of an evaluation weight, by combining
|
|
// two UCI-configurable weights (midgame and endgame) with an internal weight.
|
|
|
|
Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
|
|
|
|
// Scale option value from 100 to 256
|
|
int mg = get_option_value_int(mgOpt) * 256 / 100;
|
|
int eg = get_option_value_int(egOpt) * 256 / 100;
|
|
|
|
return apply_weight(make_score(mg, eg), internalWeight);
|
|
}
|
|
|
|
// init_safety() initizes the king safety evaluation, based on UCI
|
|
// parameters. It is called from read_weights().
|
|
|
|
void init_safety() {
|
|
|
|
const Value MaxSlope = Value(30);
|
|
const Value Peak = Value(1280);
|
|
Value t[100];
|
|
|
|
// First setup the base table
|
|
for (int i = 0; i < 100; i++)
|
|
{
|
|
t[i] = Value(int(0.4 * i * i));
|
|
|
|
if (i > 0)
|
|
t[i] = Min(t[i], t[i - 1] + MaxSlope);
|
|
|
|
t[i] = Min(t[i], Peak);
|
|
}
|
|
|
|
// Then apply the weights and get the final KingDangerTable[] array
|
|
for (Color c = WHITE; c <= BLACK; c++)
|
|
for (int i = 0; i < 100; i++)
|
|
KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
|
|
}
|
|
}
|