mirror of
https://github.com/sockspls/badfish
synced 2025-04-30 16:53:09 +00:00
48b0d41220
Avoid indirect calling of piece_of_color_and_type(c, PAWN) and its alias pawns(c) in the pawn evaluation loop, but use the pawns bitboards accessed only once before entering the loop. Also explicitly mark functions as static to better self-document. No functional change. Signed-off-by: Marco Costalba <mcostalba@gmail.com>
387 lines
13 KiB
C++
387 lines
13 KiB
C++
/*
|
|
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
|
|
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
|
|
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 <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
|
|
////
|
|
//// Includes
|
|
////
|
|
|
|
#include <cassert>
|
|
|
|
#include "bitcount.h"
|
|
#include "pawns.h"
|
|
#include "position.h"
|
|
|
|
|
|
////
|
|
//// Local definitions
|
|
////
|
|
|
|
namespace {
|
|
|
|
/// Constants and variables
|
|
|
|
// Doubled pawn penalty by file, middle game.
|
|
const Value DoubledPawnMidgamePenalty[8] = {
|
|
Value(13), Value(20), Value(23), Value(23),
|
|
Value(23), Value(23), Value(20), Value(13)
|
|
};
|
|
|
|
// Doubled pawn penalty by file, endgame.
|
|
const Value DoubledPawnEndgamePenalty[8] = {
|
|
Value(43), Value(48), Value(48), Value(48),
|
|
Value(48), Value(48), Value(48), Value(43)
|
|
};
|
|
|
|
// Isolated pawn penalty by file, middle game.
|
|
const Value IsolatedPawnMidgamePenalty[8] = {
|
|
Value(25), Value(36), Value(40), Value(40),
|
|
Value(40), Value(40), Value(36), Value(25)
|
|
};
|
|
|
|
// Isolated pawn penalty by file, endgame.
|
|
const Value IsolatedPawnEndgamePenalty[8] = {
|
|
Value(30), Value(35), Value(35), Value(35),
|
|
Value(35), Value(35), Value(35), Value(30)
|
|
};
|
|
|
|
// Backward pawn penalty by file, middle game.
|
|
const Value BackwardPawnMidgamePenalty[8] = {
|
|
Value(20), Value(29), Value(33), Value(33),
|
|
Value(33), Value(33), Value(29), Value(20)
|
|
};
|
|
|
|
// Backward pawn penalty by file, endgame.
|
|
const Value BackwardPawnEndgamePenalty[8] = {
|
|
Value(28), Value(31), Value(31), Value(31),
|
|
Value(31), Value(31), Value(31), Value(28)
|
|
};
|
|
|
|
// Pawn chain membership bonus by file, middle game.
|
|
const Value ChainMidgameBonus[8] = {
|
|
Value(11), Value(13), Value(13), Value(14),
|
|
Value(14), Value(13), Value(13), Value(11)
|
|
};
|
|
|
|
// Pawn chain membership bonus by file, endgame.
|
|
const Value ChainEndgameBonus[8] = {
|
|
Value(-1), Value(-1), Value(-1), Value(-1),
|
|
Value(-1), Value(-1), Value(-1), Value(-1)
|
|
};
|
|
|
|
// Candidate passed pawn bonus by rank, middle game.
|
|
const Value CandidateMidgameBonus[8] = {
|
|
Value( 0), Value( 6), Value(6), Value(14),
|
|
Value(34), Value(83), Value(0), Value( 0)
|
|
};
|
|
|
|
// Candidate passed pawn bonus by rank, endgame.
|
|
const Value CandidateEndgameBonus[8] = {
|
|
Value( 0), Value( 13), Value(13), Value(29),
|
|
Value(68), Value(166), Value( 0), Value( 0)
|
|
};
|
|
|
|
// Pawn storm tables for positions with opposite castling:
|
|
const int QStormTable[64] = {
|
|
0, 0, 0, 0, 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,-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 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 };
|
|
|
|
// Pawn storm lever bonuses by file
|
|
const int StormLeverBonus[8] = { -8, -8, -13, 0, 0, -13, -8, -8 };
|
|
|
|
}
|
|
|
|
|
|
////
|
|
//// Functions
|
|
////
|
|
|
|
/// Constructor
|
|
|
|
PawnInfoTable::PawnInfoTable(unsigned numOfEntries) {
|
|
|
|
size = numOfEntries;
|
|
entries = new PawnInfo[size];
|
|
if (entries == NULL)
|
|
{
|
|
std::cerr << "Failed to allocate " << (numOfEntries * sizeof(PawnInfo))
|
|
<< " bytes for pawn hash table." << std::endl;
|
|
Application::exit_with_failure();
|
|
}
|
|
}
|
|
|
|
|
|
/// Destructor
|
|
|
|
PawnInfoTable::~PawnInfoTable() {
|
|
delete [] entries;
|
|
}
|
|
|
|
|
|
/// PawnInfoTable::get_pawn_info() takes a position object as input, computes
|
|
/// 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) {
|
|
|
|
assert(pos.is_ok());
|
|
|
|
Key key = pos.get_pawn_key();
|
|
int index = int(key & (size - 1));
|
|
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 == key)
|
|
return pi;
|
|
|
|
// Clear the PawnInfo object, and set the key
|
|
pi->clear();
|
|
pi->key = key;
|
|
|
|
Value mgValue[2] = {Value(0), Value(0)};
|
|
Value egValue[2] = {Value(0), Value(0)};
|
|
|
|
// Loop through the pawns for both colors
|
|
for (Color us = WHITE; us <= BLACK; us++)
|
|
{
|
|
Color them = opposite_color(us);
|
|
Bitboard ourPawns = pos.pawns(us);
|
|
Bitboard theirPawns = pos.pawns(them);
|
|
Bitboard pawns = ourPawns;
|
|
int bonus;
|
|
|
|
// Initialize pawn storm scores by giving bonuses for open files
|
|
for (File f = FILE_A; f <= FILE_H; f++)
|
|
if (Position::file_is_half_open(ourPawns, f))
|
|
{
|
|
pi->ksStormValue[us] += KStormOpenFileBonus[f];
|
|
pi->qsStormValue[us] += QStormOpenFileBonus[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) == piece_of_color_and_type(us, PAWN));
|
|
|
|
// The file containing the pawn is not half open
|
|
pi->halfOpenFiles[us] &= ~(1 << f);
|
|
|
|
// Passed, isolated or doubled pawn?
|
|
passed = Position::pawn_is_passed(theirPawns, us, s);
|
|
isolated = Position::pawn_is_isolated(ourPawns, s);
|
|
doubled = Position::pawn_is_doubled(ourPawns, us, s);
|
|
|
|
// 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
|
|
bonus = KStormTable[relative_square(us, s)];
|
|
if (f >= FILE_F)
|
|
{
|
|
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] += 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)));
|
|
|
|
// Test for backward pawn
|
|
//
|
|
// If the pawn is passed, isolated, or member of a pawn chain
|
|
// 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.
|
|
if ( passed
|
|
|| isolated
|
|
|| chain
|
|
|| (pos.pawn_attacks(us, s) & theirPawns)
|
|
|| (ourPawns & behind_bb(us, r) & neighboring_files_bb(f)))
|
|
backward = false;
|
|
else
|
|
{
|
|
// We now know that there are no friendly pawns beside or behind this
|
|
// 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;
|
|
if (us == WHITE)
|
|
{
|
|
for (b = pos.pawn_attacks(us, s); !(b & (ourPawns | theirPawns)); b <<= 8);
|
|
backward = (b | (b << 8)) & theirPawns;
|
|
}
|
|
else
|
|
{
|
|
for (b = pos.pawn_attacks(us, s); !(b & (ourPawns | theirPawns)); b >>= 8);
|
|
backward = (b | (b >> 8)) & theirPawns;
|
|
}
|
|
}
|
|
|
|
// Test for candidate passed pawn
|
|
candidate = !passed
|
|
&& Position::file_is_half_open(theirPawns, 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 (isolated)
|
|
{
|
|
mv -= IsolatedPawnMidgamePenalty[f];
|
|
ev -= IsolatedPawnEndgamePenalty[f];
|
|
if (Position::file_is_half_open(theirPawns, f))
|
|
{
|
|
mv -= IsolatedPawnMidgamePenalty[f] / 2;
|
|
ev -= IsolatedPawnEndgamePenalty[f] / 2;
|
|
}
|
|
}
|
|
if (doubled)
|
|
{
|
|
mv -= DoubledPawnMidgamePenalty[f];
|
|
ev -= DoubledPawnEndgamePenalty[f];
|
|
}
|
|
if (backward)
|
|
{
|
|
mv -= BackwardPawnMidgamePenalty[f];
|
|
ev -= BackwardPawnEndgamePenalty[f];
|
|
if (Position::file_is_half_open(theirPawns, f))
|
|
{
|
|
mv -= BackwardPawnMidgamePenalty[f] / 2;
|
|
ev -= BackwardPawnEndgamePenalty[f] / 2;
|
|
}
|
|
}
|
|
if (chain)
|
|
{
|
|
mv += ChainMidgameBonus[f];
|
|
ev += ChainEndgameBonus[f];
|
|
}
|
|
if (candidate)
|
|
{
|
|
mv += CandidateMidgameBonus[relative_rank(us, s)];
|
|
ev += 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)
|
|
|
|
pi->mgValue = int16_t(mgValue[WHITE] - mgValue[BLACK]);
|
|
pi->egValue = int16_t(egValue[WHITE] - egValue[BLACK]);
|
|
return pi;
|
|
}
|