X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fpawns.cpp;h=96664e5c072835d37e854b90d4c6b18d50dad81c;hb=b4cb1a3a9e731015723924432293357fcdd203bc;hp=a09fe68337d8aa7ab3bbbd5f93dc86023e901fc1;hpb=ab29d8df678adb97e2bc40b04f13e4f17577ada0;p=stockfish
diff --git a/src/pawns.cpp b/src/pawns.cpp
index a09fe683..96664e5c 100644
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -1,18 +1,18 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ Copyright (C) 2008-2009 Marco Costalba
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
-
+
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
-
+
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
@@ -25,7 +25,9 @@
#include
#include
+#include "bitcount.h"
#include "pawns.h"
+#include "position.h"
////
@@ -36,100 +38,95 @@ namespace {
/// Constants and variables
- // Doubled pawn penalty by file, middle game.
+ // Doubled pawn penalty by file, middle game
const Value DoubledPawnMidgamePenalty[8] = {
- Value(20), Value(30), Value(34), Value(34),
- Value(34), Value(34), Value(30), Value(20)
+ Value(13), Value(20), Value(23), Value(23),
+ Value(23), Value(23), Value(20), Value(13)
};
- // Doubled pawn penalty by file, endgame.
+ // Doubled pawn penalty by file, endgame
const Value DoubledPawnEndgamePenalty[8] = {
- Value(35), Value(40), Value(40), Value(40),
- Value(40), Value(40), Value(40), Value(35)
+ Value(43), Value(48), Value(48), Value(48),
+ Value(48), Value(48), Value(48), Value(43)
};
- // Isolated pawn penalty by file, middle game.
+ // Isolated pawn penalty by file, middle game
const Value IsolatedPawnMidgamePenalty[8] = {
- Value(20), Value(30), Value(34), Value(34),
- Value(34), Value(34), Value(30), Value(20)
+ Value(25), Value(36), Value(40), Value(40),
+ Value(40), Value(40), Value(36), Value(25)
};
- // Isolated pawn penalty by file, endgame.
+ // Isolated pawn penalty by file, endgame
const Value IsolatedPawnEndgamePenalty[8] = {
- Value(35), Value(40), Value(40), Value(40),
- Value(40), Value(40), Value(40), Value(35)
+ Value(30), Value(35), Value(35), Value(35),
+ Value(35), Value(35), Value(35), Value(30)
};
- // Backward pawn penalty by file, middle game.
+ // Backward pawn penalty by file, middle game
const Value BackwardPawnMidgamePenalty[8] = {
- Value(16), Value(24), Value(27), Value(27),
- Value(27), Value(27), Value(24), Value(16)
+ Value(20), Value(29), Value(33), Value(33),
+ Value(33), Value(33), Value(29), Value(20)
};
- // Backward pawn penalty by file, endgame.
+ // Backward pawn penalty by file, endgame
const Value BackwardPawnEndgamePenalty[8] = {
- Value(28), Value(32), Value(32), Value(32),
- Value(32), Value(32), Value(32), Value(28)
+ Value(28), Value(31), Value(31), Value(31),
+ Value(31), Value(31), Value(31), Value(28)
};
- // Pawn chain membership bonus by file, middle game.
+ // Pawn chain membership bonus by file, middle game
const Value ChainMidgameBonus[8] = {
- Value(14), Value(16), Value(17), Value(18),
- Value(18), Value(17), Value(16), Value(14)
+ Value(11), Value(13), Value(13), Value(14),
+ Value(14), Value(13), Value(13), Value(11)
};
- // Pawn chain membership bonus by file, endgame.
+ // Pawn chain membership bonus by file, endgame
const Value ChainEndgameBonus[8] = {
- Value(16), Value(16), Value(16), Value(16),
- Value(16), Value(16), Value(16), Value(16)
+ Value(-1), Value(-1), Value(-1), Value(-1),
+ Value(-1), Value(-1), Value(-1), Value(-1)
};
- // Candidate passed pawn bonus by rank, middle game.
+ // Candidate passed pawn bonus by rank, middle game
const Value CandidateMidgameBonus[8] = {
- Value( 0), Value(12), Value(12), Value(20),
- Value(40), Value(90), Value( 0), Value( 0)
+ Value( 0), Value( 6), Value(6), Value(14),
+ Value(34), Value(83), Value(0), Value( 0)
};
- // Candidate passed pawn bonus by rank, endgame.
+ // Candidate passed pawn bonus by rank, endgame
const Value CandidateEndgameBonus[8] = {
- Value( 0), Value(24), Value(24), Value(40),
- Value(80), Value(180), Value(0), Value( 0)
+ Value( 0), Value( 13), Value(13), Value(29),
+ Value(68), Value(166), Value( 0), Value( 0)
};
- // Evaluate pawn storms?
- const bool EvaluatePawnStorms = true;
-
- // Pawn storm tables for positions with opposite castling:
+ // Pawn storm tables for positions with opposite castling
const int QStormTable[64] = {
0, 0, 0, 0, 0, 0, 0, 0,
- -22,-22,-22,-13,-4, 0, 0, 0,
- -4, -9, -9, -9,-4, 0, 0, 0,
- 9, 18, 22, 18, 9, 0, 0, 0,
- 22, 31, 31, 22, 0, 0, 0, 0,
- 31, 40, 40, 31, 0, 0, 0, 0,
- 31, 40, 40, 31, 0, 0, 0, 0,
+ -22,-22,-22,-14,-6, 0, 0, 0,
+ -6,-10,-10,-10,-6, 0, 0, 0,
+ 4, 12, 16, 12, 4, 0, 0, 0,
+ 16, 23, 23, 16, 0, 0, 0, 0,
+ 23, 31, 31, 23, 0, 0, 0, 0,
+ 23, 31, 31, 23, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
};
-
+
const int KStormTable[64] = {
- 0, 0, 0, 0, 0, 0, 0, 0,
- 0, 0, 0,-4,-13,-22,-27,-27,
- 0, 0, 0,-4, -9,-13,-18,-18,
- 0, 0, 0, 0, 9, 9, 9, 9,
- 0, 0, 0, 0, 9, 18, 27, 27,
- 0, 0, 0, 0, 9, 27, 40, 36,
- 0, 0, 0, 0, 0, 31, 40, 31,
- 0, 0, 0, 0, 0, 0, 0, 0
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0,-10,-19,-28,-33,-33,
+ 0, 0, 0,-10,-15,-19,-24,-24,
+ 0, 0, 0, 0, 1, 1, 1, 1,
+ 0, 0, 0, 0, 1, 10, 19, 19,
+ 0, 0, 0, 0, 1, 19, 31, 27,
+ 0, 0, 0, 0, 0, 22, 31, 22,
+ 0, 0, 0, 0, 0, 0, 0, 0
};
- // Pawn storm open file bonuses by file:
- const int KStormOpenFileBonus[8] = {
- 45, 45, 30, 0, 0, 0, 0, 0
- };
+ // Pawn storm open file bonuses by file
+ const int16_t KStormOpenFileBonus[8] = { 31, 31, 18, 0, 0, 0, 0, 0 };
+ const int16_t QStormOpenFileBonus[8] = { 0, 0, 0, 0, 0, 26, 42, 26 };
- const int QStormOpenFileBonus[8] = {
- 0, 0, 0, 0, 0, 30, 45, 30
- };
+ // Pawn storm lever bonuses by file
+ const int StormLeverBonus[8] = { -8, -8, -13, 0, 0, -13, -8, -8 };
}
@@ -144,13 +141,12 @@ PawnInfoTable::PawnInfoTable(unsigned numOfEntries) {
size = numOfEntries;
entries = new PawnInfo[size];
- if (entries == NULL)
+ if (!entries)
{
std::cerr << "Failed to allocate " << (numOfEntries * sizeof(PawnInfo))
<< " bytes for pawn hash table." << std::endl;
- exit(EXIT_FAILURE);
+ Application::exit_with_failure();
}
- clear();
}
@@ -161,30 +157,32 @@ PawnInfoTable::~PawnInfoTable() {
}
-/// PawnInfoTable::clear() clears the pawn hash table by setting all
-/// entries to 0.
+/// PawnInfo::clear() resets to zero the PawnInfo entry. Note that
+/// kingSquares[] is initialized to SQ_NONE instead.
+
+void PawnInfo::clear() {
-void PawnInfoTable::clear() {
- memset(entries, 0, size * sizeof(PawnInfo));
+ memset(this, 0, sizeof(PawnInfo));
+ kingSquares[WHITE] = kingSquares[BLACK] = SQ_NONE;
}
/// PawnInfoTable::get_pawn_info() takes a position object as input, computes
-/// a PawnInfo object, and returns a pointer to it. The result is also
+/// a PawnInfo 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.
-PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
+PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) {
assert(pos.is_ok());
Key key = pos.get_pawn_key();
int index = int(key & (size - 1));
- PawnInfo *pi = entries + index;
+ PawnInfo* pi = entries + index;
- // If pi->key matches the position's pawn hash key, it means that we
- // have analysed this pawn structure before, and we can simply return the
- // information we found the last time instead of recomputing it
+ // If pi->key matches the position's pawn hash key, it means that we
+ // have analysed this pawn structure before, and we can simply return
+ // the information we found the last time instead of recomputing it.
if (pi->key == key)
return pi;
@@ -204,91 +202,96 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
Bitboard pawns = ourPawns;
// Initialize pawn storm scores by giving bonuses for open files
- if (EvaluatePawnStorms)
- for(File f = FILE_A; f <= FILE_H; f++)
- if(pos.file_is_half_open(us, f))
- {
- pi->ksStormValue[us] += KStormOpenFileBonus[f];
- pi->qsStormValue[us] += QStormOpenFileBonus[f];
- }
+ for (File f = FILE_A; f <= FILE_H; f++)
+ if (!(pawns & file_bb(f)))
+ {
+ pi->ksStormValue[us] += KStormOpenFileBonus[f];
+ pi->qsStormValue[us] += QStormOpenFileBonus[f];
+ pi->halfOpenFiles[us] |= (1 << f);
+ }
// Loop through all pawns of the current color and score each pawn
while (pawns)
{
- bool passed, doubled, isolated, backward, chain, candidate;
Square s = pop_1st_bit(&pawns);
File f = square_file(s);
Rank r = square_rank(s);
- assert(pos.piece_on(s) == pawn_of_color(us));
-
- // The file containing the pawn is not half open
- pi->halfOpenFiles[us] &= ~(1 << f);
+ assert(pos.piece_on(s) == piece_of_color_and_type(us, PAWN));
// Passed, isolated or doubled pawn?
- passed = pos.pawn_is_passed(us, s);
- isolated = pos.pawn_is_isolated(us, s);
- doubled = pos.pawn_is_doubled(us, s);
+ bool passed = Position::pawn_is_passed(theirPawns, us, s);
+ bool isolated = Position::pawn_is_isolated(ourPawns, s);
+ bool doubled = Position::pawn_is_doubled(ourPawns, us, s);
- if (EvaluatePawnStorms)
+ // We calculate kingside and queenside pawn storm
+ // scores for both colors. These are used when evaluating
+ // middle game positions with opposite side castling.
+ //
+ // Each pawn is given a base score given by a piece square table
+ // (KStormTable[] or QStormTable[]). Pawns which seem to have good
+ // chances of creating an open file by exchanging itself against an
+ // enemy pawn on an adjacent file gets an additional bonus.
+
+ // Kingside pawn storms
+ int bonus = KStormTable[relative_square(us, s)];
+ if (f >= FILE_F)
{
- // We calculate kingside and queenside pawn storm scores
- // for both colors. These are used when evaluating middle
- // game positions with opposite side castling.
- //
- // Each pawn is given a base score given by a piece square table
- // (KStormTable[] or QStormTable[]). This score is increased if
- // there are enemy pawns on adjacent files in front of the pawn.
- // This is because we want to be able to open files against the
- // enemy king, and to avoid blocking the pawn structure (e.g. white
- // pawns on h6, g5, black pawns on h7, g6, f7).
-
- // Kingside and queenside pawn storms
- int KBonus = KStormTable[relative_square(us, s)];
- int QBonus = QStormTable[relative_square(us, s)];
- bool outPost = (KBonus > 0 && (outpost_mask(us, s) & theirPawns));
- bool passed = (QBonus > 0 && (passed_pawn_mask(us, s) & theirPawns));
-
- switch (f) {
-
- case FILE_A:
- QBonus += passed * QBonus / 2;
- break;
-
- case FILE_B:
- QBonus += passed * (QBonus / 2 + QBonus / 4);
- break;
-
- case FILE_C:
- QBonus += passed * QBonus / 2;
- break;
-
- case FILE_F:
- KBonus += outPost * KBonus / 4;
- break;
-
- case FILE_G:
- KBonus += outPost * (KBonus / 2 + KBonus / 4);
- break;
-
- case FILE_H:
- KBonus += outPost * KBonus / 2;
- break;
-
- default:
- break;
+ Bitboard b = outpost_mask(us, s) & theirPawns & (FileFBB | FileGBB | FileHBB);
+ while (b)
+ {
+ Square s2 = pop_1st_bit(&b);
+ if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2)))
+ {
+ // The enemy pawn has no pawn beside itself, which makes it
+ // particularly vulnerable. Big bonus, especially against a
+ // weakness on the rook file.
+ if (square_file(s2) == FILE_H)
+ bonus += 4*StormLeverBonus[f] - 8*square_distance(s, s2);
+ else
+ bonus += 2*StormLeverBonus[f] - 4*square_distance(s, s2);
+ } else
+ // There is at least one enemy pawn beside the enemy pawn we look
+ // at, which means that the pawn has somewhat better chances of
+ // defending itself by advancing. Smaller bonus.
+ bonus += StormLeverBonus[f] - 2*square_distance(s, s2);
}
- pi->ksStormValue[us] += KBonus;
- pi->qsStormValue[us] += QBonus;
}
+ pi->ksStormValue[us] += bonus;
+
+ // Queenside pawn storms
+ bonus = QStormTable[relative_square(us, s)];
+ if (f <= FILE_C)
+ {
+ Bitboard b = outpost_mask(us, s) & theirPawns & (FileABB | FileBBB | FileCBB);
+ while (b)
+ {
+ Square s2 = pop_1st_bit(&b);
+ if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2)))
+ {
+ // The enemy pawn has no pawn beside itself, which makes it
+ // particularly vulnerable. Big bonus, especially against a
+ // weakness on the rook file.
+ if (square_file(s2) == FILE_A)
+ bonus += 4*StormLeverBonus[f] - 16*square_distance(s, s2);
+ else
+ bonus += 2*StormLeverBonus[f] - 8*square_distance(s, s2);
+ } else
+ // There is at least one enemy pawn beside the enemy pawn we look
+ // at, which means that the pawn has somewhat better chances of
+ // defending itself by advancing. Smaller bonus.
+ bonus += StormLeverBonus[f] - 4*square_distance(s, s2);
+ }
+ }
+ pi->qsStormValue[us] += bonus;
// Member of a pawn chain (but not the backward one)? We could speed up
// the test a little by introducing an array of masks indexed by color
// and square for doing the test, but because everything is hashed,
// it probably won't make any noticable difference.
- chain = ourPawns
- & neighboring_files_bb(f)
- & (rank_bb(r) | rank_bb(r - (us == WHITE ? 1 : -1)));
+ bool chain = ourPawns
+ & neighboring_files_bb(f)
+ & (rank_bb(r) | rank_bb(r - (us == WHITE ? 1 : -1)));
// Test for backward pawn
//
@@ -296,6 +299,7 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
// it cannot be backward. If can capture an enemy pawn or if
// there are friendly pawns behind on neighboring files it cannot
// be backward either.
+ bool backward;
if ( passed
|| isolated
|| chain
@@ -308,80 +312,72 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
// pawn on neighboring files. We now check whether the pawn is
// backward by looking in the forward direction on the neighboring
// files, and seeing whether we meet a friendly or an enemy pawn first.
- Bitboard b;
+ Bitboard b = pos.pawn_attacks(us, s);
if (us == WHITE)
{
- for (b = pos.pawn_attacks(us, s); !(b & (ourPawns | theirPawns)); b <<= 8);
+ for ( ; !(b & (ourPawns | theirPawns)); b <<= 8);
backward = (b | (b << 8)) & theirPawns;
}
else
{
- for (b = pos.pawn_attacks(us, s); !(b & (ourPawns | theirPawns)); b >>= 8);
+ for ( ; !(b & (ourPawns | theirPawns)); b >>= 8);
backward = (b | (b >> 8)) & theirPawns;
}
}
// Test for candidate passed pawn
+ bool candidate;
candidate = !passed
- && pos.file_is_half_open(them, f)
- && ( count_1s_max_15(neighboring_files_bb(f) & (behind_bb(us, r) | rank_bb(r)) & ourPawns)
- - count_1s_max_15(neighboring_files_bb(f) & in_front_bb(us, r) & theirPawns)
- >= 0);
+ && !(theirPawns & file_bb(f))
+ && ( count_1s_max_15(neighboring_files_bb(f) & (behind_bb(us, r) | rank_bb(r)) & ourPawns)
+ - count_1s_max_15(neighboring_files_bb(f) & in_front_bb(us, r) & theirPawns)
+ >= 0);
// In order to prevent doubled passed pawns from receiving a too big
// bonus, only the frontmost passed pawn on each file is considered as
// a true passed pawn.
if (passed && (ourPawns & squares_in_front_of(us, s)))
- {
- // candidate = true;
passed = false;
- }
// Score this pawn
- Value mv = Value(0), ev = Value(0);
+ if (passed)
+ set_bit(&(pi->passedPawns), s);
+
if (isolated)
{
- mv -= IsolatedPawnMidgamePenalty[f];
- ev -= IsolatedPawnEndgamePenalty[f];
- if (pos.file_is_half_open(them, f))
+ mgValue[us] -= IsolatedPawnMidgamePenalty[f];
+ egValue[us] -= IsolatedPawnEndgamePenalty[f];
+ if (!(theirPawns & file_bb(f)))
{
- mv -= IsolatedPawnMidgamePenalty[f] / 2;
- ev -= IsolatedPawnEndgamePenalty[f] / 2;
+ mgValue[us] -= IsolatedPawnMidgamePenalty[f] / 2;
+ egValue[us] -= IsolatedPawnEndgamePenalty[f] / 2;
}
}
if (doubled)
{
- mv -= DoubledPawnMidgamePenalty[f];
- ev -= DoubledPawnEndgamePenalty[f];
+ mgValue[us] -= DoubledPawnMidgamePenalty[f];
+ egValue[us] -= DoubledPawnEndgamePenalty[f];
}
if (backward)
{
- mv -= BackwardPawnMidgamePenalty[f];
- ev -= BackwardPawnEndgamePenalty[f];
- if (pos.file_is_half_open(them, f))
+ mgValue[us] -= BackwardPawnMidgamePenalty[f];
+ egValue[us] -= BackwardPawnEndgamePenalty[f];
+ if (!(theirPawns & file_bb(f)))
{
- mv -= BackwardPawnMidgamePenalty[f] / 2;
- ev -= BackwardPawnEndgamePenalty[f] / 2;
+ mgValue[us] -= BackwardPawnMidgamePenalty[f] / 2;
+ egValue[us] -= BackwardPawnEndgamePenalty[f] / 2;
}
}
if (chain)
{
- mv += ChainMidgameBonus[f];
- ev += ChainEndgameBonus[f];
+ mgValue[us] += ChainMidgameBonus[f];
+ egValue[us] += ChainEndgameBonus[f];
}
if (candidate)
{
- mv += CandidateMidgameBonus[relative_rank(us, s)];
- ev += CandidateEndgameBonus[relative_rank(us, s)];
+ mgValue[us] += CandidateMidgameBonus[relative_rank(us, s)];
+ egValue[us] += CandidateEndgameBonus[relative_rank(us, s)];
}
-
- mgValue[us] += mv;
- egValue[us] += ev;
-
- // If the pawn is passed, set the square of the pawn in the passedPawns
- // bitboard
- if (passed)
- set_bit(&(pi->passedPawns), s);
} // while(pawns)
} // for(colors)
@@ -389,3 +385,21 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
pi->egValue = int16_t(egValue[WHITE] - egValue[BLACK]);
return pi;
}
+
+
+/// PawnInfo::updateShelter calculates and caches king shelter. It is called
+/// only when king square changes, about 20% of total get_king_shelter() calls.
+int PawnInfo::updateShelter(const Position& pos, Color c, Square ksq) {
+
+ unsigned shelter = 0;
+ Bitboard pawns = pos.pawns(c) & this_and_neighboring_files_bb(ksq);
+ unsigned r = ksq & (7 << 3);
+ for (int i = 1, k = (c ? -8 : 8); i < 4; i++)
+ {
+ r += k;
+ shelter += BitCount8Bit[(pawns >> r) & 0xFF] * (128 >> i);
+ }
+ kingSquares[c] = ksq;
+ kingShelters[c] = shelter;
+ return shelter;
+}