/*
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 "bitcount.h"
#include "pawns.h"
#include "position.h"
+#include "thread.h"
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
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<PAWN>(Us);
const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)];
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<PAWN>(s, Us) & theirPawns))
+ // it cannot be backward either.
+ if ( (passed | isolated | connected | lever)
+ || (ourPawns & pawn_attack_span(Them, s)))
backward = false;
else
{
// 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<Rank>(s, frontmost_sq(Us, doubled));
+ score -= Doubled[f] / distance<Rank>(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()
{
}
-/// 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<WHITE>(pos, e) - evaluate<BLACK>(pos, e);
+ e->score = evaluate<WHITE>(pos, e) - evaluate<BLACK>(pos, e);
return e;
}
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]);
projects / stockfish / blobdiff