X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=798bc0a070319dc846986535e4480d9e3442d349;hp=b26b1be656cda8a599ca2a00d8405fd45317ac9b;hb=8aa8608c2a30acc56c4bb4467309cef5089fb2bd;hpb=296534f23489e6d95ba7ce1bb35e8a2cbf9a5a9d diff --git a/src/pawns.cpp b/src/pawns.cpp index b26b1be6..798bc0a0 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -24,6 +24,7 @@ #include "bitcount.h" #include "pawns.h" #include "position.h" +#include "thread.h" namespace { @@ -62,33 +63,33 @@ namespace { // Weakness of our pawn shelter in front of the king by [distance from edge][rank] const Value ShelterWeakness[][RANK_NB] = { - { V(101), V(10), V(24), V(68), V(90), V( 95), V(102) }, - { V(105), V( 1), V(30), V(76), V(95), V(100), V(105) }, - { V( 99), V( 0), V(32), V(72), V(92), V(101), V(100) }, - { V( 94), V( 1), V(31), V(68), V(89), V( 98), V(106) } }; + { V( 99), V(23), V(24), V(54), V(85), V( 93), V(107) }, + { V(119), V( 2), V(28), V(72), V(96), V(104), V(114) }, + { V(103), V( 6), V(47), V(74), V(84), V(103), V( 94) }, + { V( 78), V(10), V(41), V(64), V(88), V( 92), V(115) } }; // Danger of enemy pawns moving toward our king by [type][distance from edge][rank] const Value StormDanger[][4][RANK_NB] = { - { { V( 0), V( 61), V( 128), V(47), V(27) }, - { V( 0), V( 66), V( 131), V(49), V(27) }, - { V( 0), V( 62), V( 126), V(52), V(23) }, - { V( 0), V( 63), V( 128), V(52), V(26) } }, - { { V(25), V( 33), V( 95), V(39), V(21) }, - { V(24), V( 33), V( 97), V(42), V(22) }, - { V(24), V( 33), V( 93), V(35), V(23) }, - { V(26), V( 27), V( 96), V(37), V(22) } }, - { { V( 0), V( 0), V( 80), V(14), V( 8) }, - { V( 0), V( 0), V( 163), V(28), V(12) }, - { V( 0), V( 0), V( 163), V(25), V(15) }, - { V( 0), V( 0), V( 161), V(24), V(14) } }, - { { V( 0), V(-300), V(-300), V(54), V(23) }, - { V( 0), V( 67), V( 128), V(46), V(24) }, - { V( 0), V( 64), V( 130), V(50), V(29) }, - { V( 0), V( 63), V( 127), V(51), V(24) } } }; + { { V( 0), V( 65), V( 125), V(37), V(30) }, + { V( 0), V( 57), V( 136), V(39), V(24) }, + { V( 0), V( 50), V( 114), V(45), V(29) }, + { V( 0), V( 58), V( 129), V(56), V(34) } }, + { { V(20), V( 45), V( 91), V(47), V(20) }, + { V(25), V( 23), V( 105), V(38), V(14) }, + { V(21), V( 37), V( 99), V(35), V(21) }, + { V(30), V( 18), V( 105), V(38), V(28) } }, + { { V( 0), V( 0), V( 81), V(13), V( 4) }, + { V( 0), V( 0), V( 169), V(30), V( 4) }, + { V( 0), V( 0), V( 166), V(24), V( 6) }, + { V( 0), V( 0), V( 164), V(24), V(11) } }, + { { V( 0), V(-289), V(-297), V(57), V(29) }, + { V( 0), V( 66), V( 136), V(43), V(16) }, + { V( 0), V( 66), V( 141), V(50), V(31) }, + { V( 0), V( 63), V( 126), V(52), V(23) } } }; // Max bonus for king safety. Corresponds to start position with all the pawns // in front of the king and no enemy pawn on the horizon. - const Value MaxSafetyBonus = V(261); + const Value MaxSafetyBonus = V(252); #undef S #undef V @@ -104,7 +105,7 @@ namespace { Bitboard b, p, doubled, connected; Square s; bool passed, isolated, opposed, phalanx, backward, unsupported, lever; - Score value = SCORE_ZERO; + Score score = SCORE_ZERO; const Square* pl = pos.list(Us); const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)]; @@ -143,12 +144,11 @@ namespace { lever = theirPawns & pawnAttacksBB[s]; // Test for backward pawn. - // If the pawn is passed, isolated, or connected it cannot be + // If the pawn is passed, isolated, connected or a lever it cannot be // backward. If there are friendly pawns behind on adjacent files - // or if it can capture an enemy pawn it cannot be backward either. - if ( (passed | isolated | connected) - || (ourPawns & pawn_attack_span(Them, s)) - || (pos.attacks_from(s, Us) & theirPawns)) + // it cannot be backward either. + if ( (passed | isolated | connected | lever) + || (ourPawns & pawn_attack_span(Them, s))) backward = false; else { @@ -174,37 +174,37 @@ namespace { // Score this pawn if (isolated) - value -= Isolated[opposed][f]; + score -= Isolated[opposed][f]; if (unsupported && !isolated) - value -= UnsupportedPawnPenalty; + score -= UnsupportedPawnPenalty; if (doubled) - value -= Doubled[f] / distance(s, frontmost_sq(Us, doubled)); + score -= Doubled[f] / distance(s, frontmost_sq(Us, doubled)); if (backward) - value -= Backward[opposed][f]; + score -= Backward[opposed][f]; if (connected) - value += Connected[opposed][phalanx][relative_rank(Us, s)]; + score += Connected[opposed][phalanx][relative_rank(Us, s)]; if (lever) - value += Lever[relative_rank(Us, s)]; + score += Lever[relative_rank(Us, s)]; } b = e->semiopenFiles[Us] ^ 0xFF; e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0; - return value; + return score; } } // namespace namespace Pawns { -/// init() initializes some tables used by evaluation. Instead of hard-coded -/// tables, when makes sense, we prefer to calculate them with a formula to -/// reduce independent parameters and to allow easier tuning and better insight. +/// Pawns::init() initializes some tables needed by evaluation. Instead of using +/// hard-coded tables, when makes sense, we prefer to calculate them with a formula +/// to reduce independent parameters and to allow easier tuning and better insight. void init() { @@ -220,20 +220,21 @@ void init() } -/// probe() takes a position as input, computes a Entry object, and returns a -/// pointer to it. The result is also stored in a hash table, so we don't have -/// to recompute everything when the same pawn structure occurs again. +/// Pawns::probe() looks up the current position's pawns configuration in +/// the pawns hash table. It returns a pointer to the Entry if the position +/// is found. Otherwise a new Entry is computed and stored there, so we don't +/// have to recompute all when the same pawns configuration occurs again. -Entry* probe(const Position& pos, Table& entries) { +Entry* probe(const Position& pos) { Key key = pos.pawn_key(); - Entry* e = entries[key]; + Entry* e = pos.this_thread()->pawnsTable[key]; if (e->key == key) return e; e->key = key; - e->value = evaluate(pos, e) - evaluate(pos, e); + e->score = evaluate(pos, e) - evaluate(pos, e); return e; } @@ -286,7 +287,7 @@ Score Entry::do_king_safety(const Position& pos, Square ksq) { Bitboard pawns = pos.pieces(Us, PAWN); if (pawns) - while (!(DistanceRingsBB[ksq][minKingPawnDistance[Us]++] & pawns)) {} + while (!(DistanceRingBB[ksq][minKingPawnDistance[Us]++] & pawns)) {} if (relative_rank(Us, ksq) > RANK_4) return make_score(0, -16 * minKingPawnDistance[Us]);