yanis/dartsunfish
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Compare commits

merge into: yanis:master
Branches Tags
yanis:master yanis:splited_structure
...
pull from: yanis:splited_structure
Branches Tags
yanis:splited_structure yanis:master

2 Commits
master ... splited_st

Author SHA1 Message Date
DMK
c1188922c8 Stack at searcher 2021-08-20 10:55:48 +03:00
DMK
186870e770 Split singe file into set of src files 2021-08-01 21:13:25 +03:00
14 changed files with 1418 additions and 718 deletions
Expand all files Collapse all files

2
bin/dartsunfish.dart
View File

@@ -1,4 +1,4 @@
import 'package:dartsunfish/dartsunfish.dart' as dartsunfish; import 'package:dartsunfish/index.dart' as dartsunfish;
void main(List<String> arguments) { void main(List<String> arguments) {
dartsunfish.GameBot().playGame(); dartsunfish.GameBot().playGame();

715
lib/dartsunfish.dart
View File

@@ -1,715 +0,0 @@
import 'dart:io';
import 'dart:math';
import 'dart:developer' as dv;
///String extentions
extension CheckString on String {
bool get isSpace => trim().isEmpty || RegExp(r'/\s/').hasMatch(this);
bool get isUpper => !isSpace && toUpperCase() == this && this != '.';
bool get isLower => !isSpace && toLowerCase() == this && this != '.';
String get reversed => split('').reversed.join('');
String get swapCase =>
split('').map((x) => x.toUpperCase() == x ? x.toLowerCase() : x.toUpperCase()).toList().join('');
String get reversedAndSwapCased =>
split('').map((x) => x.toUpperCase() == x ? x.toLowerCase() : x.toUpperCase()).toList().reversed.join('');
}
// List of list extention
extension CheckListOfTuples on List {
bool doContains(newList) => newList.length == 2 && indexWhere((l) => l[0] == newList[0] && l[1] == newList[1]) > -1;
}
int getSeconds() {
return DateTime.now().millisecondsSinceEpoch ~/ 1000.toInt();
}
// //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// // Piece-Square tables. Tune these to change sunfish's behaviour
// //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/// TODO: add wizard
final piece = {'P': 100, 'N': 280, 'B': 320, 'R': 479, 'Q': 929, 'K': 60000};
///TODO: add 2 raws and 2 colums to each set AND Wizard pst
var pst = {
'P': [
0, 0, 0, 0, 0, 0, 0, 0, //
78, 83, 86, 73, 102, 82, 85, 90, //
7, 29, 21, 44, 40, 31, 44, 7, //
-17, 16, -2, 15, 14, 0, 15, -13, //
-26, 3, 10, 9, 6, 1, 0, -23, //
-22, 9, 5, -11, -10, -2, 3, -19, //
-31, 8, -7, -37, -36, -14, 3, -31, //
0, 0, 0, 0, 0, 0, 0, 0
], //
'N': [
-66, -53, -75, -75, -10, -55, -58, -70, //
-3, -6, 100, -36, 4, 62, -4, -14, //
10, 67, 1, 74, 73, 27, 62, -2, //
24, 24, 45, 37, 33, 41, 25, 17, //
-1, 5, 31, 21, 22, 35, 2, 0, //
-18, 10, 13, 22, 18, 15, 11, -14, //
-23, -15, 2, 0, 2, 0, -23, -20, //
-74, -23, -26, -24, -19, -35, -22, -69
], //
'B': [
-59, -78, -82, -76, -23, -107, -37, -50, //
-11, 20, 35, -42, -39, 31, 2, -22, //
-9, 39, -32, 41, 52, -10, 28, -14, //
25, 17, 20, 34, 26, 25, 15, 10, //
13, 10, 17, 23, 17, 16, 0, 7, //
14, 25, 24, 15, 8, 25, 20, 15, //
19, 20, 11, 6, 7, 6, 20, 16, //
-7, 2, -15, -12, -14, -15, -10, -10
], //
'R': [
35, 29, 33, 4, 37, 33, 56, 50, //
55, 29, 56, 67, 55, 62, 34, 60, //
19, 35, 28, 33, 45, 27, 25, 15, //
0, 5, 16, 13, 18, -4, -9, -6, //
-28, -35, -16, -21, -13, -29, -46, -30, //
-42, -28, -42, -25, -25, -35, -26, -46, //
-53, -38, -31, -26, -29, -43, -44, -53, //
-30, -24, -18, 5, -2, -18, -31, -32
], //
'Q': [
6, 1, -8, -104, 69, 24, 88, 26, //
14, 32, 60, -10, 20, 76, 57, 24, //
-2, 43, 32, 60, 72, 63, 43, 2, //
1, -16, 22, 17, 25, 20, -13, -6, //
-14, -15, -2, -5, -1, -10, -20, -22, //
-30, -6, -13, -11, -16, -11, -16, -27, //
-36, -18, 0, -19, -15, -15, -21, -38, //
-39, -30, -31, -13, -31, -36, -34, -42
], //
'K': [
4, 54, 47, -99, -99, 60, 83, -62, //
-32, 10, 55, 56, 56, 55, 10, 3, //
-62, 12, -57, 44, -67, 28, 37, -31, //
-55, 50, 11, -4, -19, 13, 0, -49, //
-55, -43, -52, -28, -51, -47, -8, -50, //
-47, -42, -43, -79, -64, -32, -29, -32, //
-4, 3, -14, -50, -57, -18, 13, 4, //
17, 30, -3, -14, 6, -1, 40, 18
], //
};
// recalculating Piece-Square raw into desk surrounded by 0-s
List<int> padrow(List<int> row, String k) {
var rowBody = <int>[for (int x in row) x + piece[k]!];
return [
0,
...rowBody,
0,
];
}
void setPst() {
pst.forEach((key, item) {
final innerItem = [...List.filled(20, 0)];
for (var i = 0; i < 8; i++) {
innerItem.addAll(padrow(item.getRange(i * 8, i * 8 + 8).toList(), key));
}
innerItem.addAll(List.filled(20, 0));
pst[key] = innerItem;
});
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Global constants
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Our board is represented as a 120 character string. The padding allows for
// fast detection of moves that don't stay within the board.
//TODO: Tune globals for 10x10 field
final A1 = 91, H1 = 98, A8 = 21, H8 = 28;
final initial = (' \n' // 0 - 9
' \n' // 10 - 19
' rnbqkbnr\n' // 20 - 29
' pppppppp\n' // 30 - 39
' ........\n' // 40 - 49
' ........\n' // 50 - 59
' ........\n' // 60 - 69
' ........\n' // 70 - 79
' PPPPPPPP\n' // 80 - 89
' RNBQKBNR\n' // 90 - 99
' \n' // 100 -109
' \n' // 110 -119
);
// Lists of possible moves for each piece type.
int N = -10, E = 1, S = 10, W = -1;
//TODO: add directions for Wizard
final Map<String?, List<int>> directions = {
'P': [N, N + N, N + W, N + E],
'N': [N + N + E, E + N + E, E + S + E, S + S + E, S + S + W, W + S + W, W + N + W, N + N + W],
'B': [N + E, S + E, S + W, N + W],
'R': [N, E, S, W],
'Q': [N, E, S, W, N + E, S + E, S + W, N + W],
'K': [N, E, S, W, N + E, S + E, S + W, N + W],
'.': []
};
// Mate value must be greater than 8*queen + 2*(rook+knight+bishop)
// King value is set to twice this value such that if the opponent is
// 8 queens up, but we got the king, we still exceed MATE_VALUE.
// When a MATE is detected, we'll set the score to MATE_UPPER - plies to get there
// E.g. Mate in 3 will be MATE_UPPER - 6
// TOD: replace mate with King capture event
final MATE_LOWER = piece['K']! - 10 * piece['Q']!;
final MATE_UPPER = piece['K']! + 10 * piece['Q']!;
// The table size is the maximum number of elements in the transposition table.
final TABLE_SIZE = 1e7;
// Constants for tuning search
final QS_LIMIT = 219, EVAL_ROUGHNESS = 13, DRAW_TEST = true;
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Chess logic
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
class Position {
Position(
this.board,
this.score,
this.wc,
this.bc,
this.ep,
this.kp,
);
String board;
int score;
List<bool> wc;
List<bool> bc;
int ep;
int kp;
/*
""" A state of a chess game
board -- a 120 char representation of the board
score -- the board evaluation
wc -- the castling rights, [west/queen side, east/king side]
bc -- the opponent castling rights, [west/king side, east/queen side]
ep - the en passant square
kp - the king passant square
""";
*/
Iterable<List<int>> gen_moves() sync* {
// For each of our pieces, iterate through each possible 'ray' of moves,
// as defined in the 'directions' map. The rays are broken e.g. by
// captures or immediately in case of pieces such as knights.
//TODO: add limitation of 3 cells for Wizard
final charsList = board.split('');
for (var i = 0; i < board.length; i++) {
final p = charsList[i];
// yield ([i, 12]);
// }
// board.split('').asMap().forEach((i, p) sync* {
if (!p.isUpper) {
continue;
}
for (var d in directions[p]!) {
for (var j in count(i + d, d)) {
final q = board[j];
// Stay inside the board, and off friendly pieces
if (q.isSpace || q.isUpper) {
break;
}
// Pawn move, double move and capture
if (p == 'P' && [N, N + N].contains(d) && q != '.') {
break;
}
if (p == 'P' && d == (N + N) && (i < A1 + N || board[i + N] != '.')) {
break;
}
if (p == 'P' && [N + W, N + E].contains(d) && q == '.' && ![ep, kp, kp - 1, kp + 1].contains(j)) {
break;
}
// Move it
final res = [i, j];
yield (res);
// Stop crawlers from sliding, and sliding after captures
if ('PNK'.contains(p) || q.isLower) {
break;
}
// Castling, by sliding the rook next to the king
if (i == A1 && board[j + E] == 'K' && wc[0]) {
yield ([j + E, j + W]);
}
if (i == H1 && board[j + W] == 'K' && wc[1]) {
yield ([j + W, j + E]);
}
}
}
}
}
// String reversed(String subject) {
// return subject.split('').reversed.join();
// }
String swapCase(String subject) {
if (subject is! String || subject.isEmpty) {
return '';
}
String _swap(String l) {
if (l.toUpperCase() == l) {
return l.toLowerCase();
} else {
return l.toUpperCase();
}
}
var subjectChars = subject.split('');
return subjectChars.map((x) => _swap(x)).join();
}
Position rotate() {
''' Rotates the board, preserving enpassant ''';
return Position(board.reversedAndSwapCased, -score, bc, wc, ep > 0 ? 119 - ep : 0, kp > 0 ? 119 - kp : 0);
}
Position nullmove() {
''' Like rotate, but clears ep and kp ''';
return Position(board.reversedAndSwapCased, -score, bc, wc, 0, 0);
}
String put(String _str, int i, String p) {
final newStr = _str.substring(0, i) + p + _str.substring(i + 1);
return newStr;
}
// move piece due to the move scecification
Position movePiece(List<int> move) {
final i = move[0], j = move[1];
final p = board[i];
final q = board[j];
// Copy variables and reset ep and kp
var _board = board;
var _wc = wc, _bc = bc, _ep = 0, _kp = 0;
score = score + value(move);
// Actual move
board = put(_board, j, p);
board = put(board, i, '.');
// Castling rights, we move the rook or capture the opponent's
if (i == A1) {
_wc = [false, wc[1]];
}
if (i == H1) {
_wc = [wc[0], false];
}
if (j == A8) {
bc = [bc[0], false];
}
if (j == H8) {
bc = [false, bc[1]];
}
// Castling
if (p == 'K') {
_wc = [false, false];
if ((j - i).abs() == 2) {
kp = (i + j); //2
board = put(board, (j < i) ? A1 : H1, '.');
board = put(board, kp, 'R');
}
}
// Pawn promotion, double move and en passant capture
if (p == 'P') {
if (A8 <= j && j <= H8) {
board = put(board, j, 'Q');
}
if (j - i == 2 * N) {
ep = i + N;
}
if (j == ep) {
board = put(board, j + S, '.');
}
}
// We rotate the returned position, so it's ready for the next player
return Position(board, score, _wc, _bc, _ep, _kp).rotate();
}
// calculate score of the board position
int value(List<int> move) {
final i = move[0], j = move[1];
final p = board[i], q = board[j];
// Actual move
score = pst[p] != null ? pst[p]![j] - pst[p]![i] : 0;
// Capture
if (!q.isUpper) {
score += pst[q.toUpperCase()] != null ? pst[q.toUpperCase()]![119 - j] : 0;
}
// Castling check detection
if ((j - kp).abs() < 2) {
score += pst['K']![119 - j];
}
// Castling
if (p == 'K' && (i - j).abs() == 2) {
score += pst['R']![(i + j)]; //2]
score -= pst['R']![j < i ? A1 : H1];
}
// Special pawn stuff
if (p == 'P') {
if (A8 <= j && j <= H8) {
score += pst['Q']![j] - pst['P']![j];
}
if (j == ep) {
score += pst['P']![119 - (j + S)];
}
}
return score;
}
/// python counter immulation
Iterable<int> count(int firstval, int step) sync* {
var x = firstval;
while (true) {
yield (x);
x += step;
}
}
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Search logic
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// lower <= s(pos) <= upper
class Entry {
Entry(this.lower, this.upper);
int lower;
int upper;
}
class Searcher {
Searcher();
late Map<List, Entry> tpScore = {};
late Map<Position, List<int>?> tpMove = {};
late Set<Position> history;
int nodes = 0;
int bound(Position pos, int gamma, int depth, {bool root = true}) {
''' returns r where
s(pos) <= r < gamma if gamma > s(pos)
gamma <= r <= s(pos) if gamma <= s(pos)''';
nodes += 1;
// Depth <= 0 is QSearch. Here any position is searched as deeply as is needed for
// calmness, and from this point on there is no difference in behaviour depending on
// depth, so so there is no reason to keep different depths in the transposition table.
depth = max(depth, 0);
// Sunfish is a king-capture engine, so we should always check if we
// still have a king. Notice since this is the only termination check,
// the remaining code has to be comfortable with being mated, stalemated
// or able to capture the opponent king.
if (pos.score <= -MATE_LOWER) {
return -MATE_UPPER;
}
// We detect 3-fold captures by comparing against previously
// _actually played_ positions.
// Note that we need to do this before we look in the table, as the
// position may have been previously reached with a different score.
// This is what prevents a search instability.
// FIXME: This is not true, since other positions will be affected by
// the new values for all the drawn positions.
if (DRAW_TEST) {
if (!root && history.contains(pos)) {
return 0;
}
}
// Look in the table if we have already searched this position before.
// We also need to be sure, that the stored search was over the same
// nodes as the current search.
var entry = tpScore[[pos, depth, root]] ?? Entry(-MATE_UPPER, MATE_UPPER);
if (entry.lower >= gamma && (!root || tpMove[pos] != null)) {
return entry.lower;
}
if (entry.upper < gamma) {
return entry.upper;
}
// Here extensions may be added
// Such as 'if in_check: depth += 1'
// Generator of moves to search in order.
// This allows us to define the moves, but only calculate them if needed.
Iterable<List<dynamic>> moves() sync* {
// First try not moving at all. We only do this if there is at least one major
// piece left on the board, since otherwise zugzwangs are too dangerous.
// if (depth > 0 && !root && any(c in pos.board for c in 'RBNQ')){
if (depth > 0 && !root && pos.board.split('').any((c) => 'RBNQ'.contains(c))) {
// print('post 1st condition');
yield ([null, -1 * bound(pos.nullmove(), 1 - gamma, depth - 3, root: false)]);
}
// For QSearch we have a different kind of null-move, namely we can just stop
// and not capture anything else.
if (depth == 0) {
// print('post 2nd condition');
yield ([null, pos.score]);
}
// Then killer move. We search it twice, but the tp will fix things for us.
// Note, we don't have to check for legality, since we've already done it
// before. Also note that in QS the killer must be a capture, otherwise we
// will be non deterministic.
var killer = tpMove[pos];
if (killer != null && (depth > 0 || pos.value(killer) >= QS_LIMIT)) {
// print('post killer');
yield ([killer, -1 * bound(pos.movePiece(killer), 1 - gamma, depth - 1, root: false)]);
}
// Then all the other moves
var possibleMoves = pos.gen_moves().toList()
..sort((a, b) => pos.value(a).compareTo(pos.value(b)))
..toList(); //.reversed;
for (var move in possibleMoves.reversed) {
//pos.gen_moves().toList().sort((a, b) => a.value.compareto(b.value)).toList().reversed)) {
// for val, move in sorted(((pos.value(move), move) for move in pos.gen_moves()), reverse=true):
// If depth == 0 we only try moves with high intrinsic score (captures and
// promotions). Otherwise we do all moves.
if (depth > 0 || pos.value(move) >= QS_LIMIT) {
yield ([move, -1 * bound(pos.movePiece(move), 1 - gamma, depth - 1, root: false)]);
}
}
}
// Run through the moves, shortcutting when possible
var best = -MATE_UPPER;
for (var m in moves()) {
List<int>? move = m[0];
int score = m[1];
best = max(best, score);
// if (depth == 0){
// print([
// 'Depth',
// depth,
// 'Move',
// move != null ? UI.render(119 - move[0]) + UI.render(119 - move[1]) : 'No move',
// 'Score',
// score,
// 'Best',
// best,
// 'Gamma',
// gamma,
// 'STOP',
// best >= gamma
// ]);}
if (best >= gamma) {
// Clear before setting, so we always have a value
if (tpMove.length > TABLE_SIZE) {
tpMove.clear();
}
// Save the move for pv construction and killer heuristic
tpMove[pos] = move;
break;
}
}
// Stalemate checking is a bit tricky: Say we failed low, because
// we can't (legally) move and so the (real) score is -infty.
// At the next depth we are allowed to just return r, -infty <= r < gamma,
// which is normally fine.
// However, what if gamma = -10 and we don't have any legal moves?
// Then the score is actaully a draw and we should fail high!
// Thus, if best < gamma and best < 0 we need to double check what we are doing.
// This doesn't prevent sunfish from making a move that results in stalemate,
// but only if depth == 1, so that's probably fair enough.
// (Btw, at depth 1 we can also mate without realizing.)
if (best < gamma && best < 0 && depth > 0) {
bool is_dead(pos) {
return pos.value.any((m) => m >= MATE_LOWER);
}
// if (all(is_dead(pos.move(m)) for m in pos.gen_moves())){
if (pos.gen_moves().every((m) => is_dead(pos.movePiece(m)))) {
var in_check = is_dead(pos.nullmove());
best = in_check ? -MATE_UPPER : 0;
}
}
// Clear before setting, so we always have a value
if (tpScore.length > TABLE_SIZE) {
tpScore.clear();
}
// Table part 2
if (best >= gamma) {
tpScore[[pos, depth, root]] = Entry(best, entry.upper);
}
if (best < gamma) {
tpScore[[pos, depth, root]] = Entry(entry.lower, best);
}
return best;
}
Iterable<dynamic> search(Position pos, Set<Position> _history) sync* {
''' Iterative deepening MTD-bi search ''';
nodes = 0;
if (DRAW_TEST) {
history = _history;
// print('// Clearing table due to new history')
tpScore.clear();
}
// In finished games, we could potentially go far enough to cause a recursion
// limit exception. Hence we bound the ply.
for (var depth = 1; depth < 1000; depth++) {
// The inner loop is a binary search on the score of the position.
// Inv: lower <= score <= upper
// 'while lower != upper' would work, but play tests show a margin of 20 plays
// better.
var lower = -MATE_UPPER;
var upper = MATE_UPPER;
while (lower < upper - EVAL_ROUGHNESS) {
var gamma = (lower + upper + 1) ~/ 2;
var score = bound(pos, gamma, depth);
if (score >= gamma) lower = score;
if (score < gamma) upper = score;
}
// We want to make sure the move to play hasn't been kicked out of the table,
// So we make another call that must always fail high and thus produce a move.
// bound(pos, lower, depth);
// If the game hasn't finished we can retrieve our move from the
// transposition table.
yield ([
depth,
tpMove[pos],
tpScore[[pos, depth, true]]?.lower
]);
}
}
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// User interface
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
class UI {
static int parse(String? c) {
var fil = c![0].codeUnits.first - 'a'.codeUnits.first;
var rank = int.parse(c[1]) - 1;
return A1 + fil - 10 * rank;
}
static String render(int i) {
var rank = (i - A1) ~/ 10;
var fil = (i - A1) % 10;
return String.fromCharCodes([fil + 'a'.codeUnits.first]) + (-rank + 1).toString();
}
static void printBoard(Position pos) {
final uni_pieces = {
'R': '♜',
'N': '♞',
'B': '♝',
'Q': '♛',
'K': '♚',
'P': '♟',
'r': '♖',
'n': '♘',
'b': '♗',
'q': '♕',
'k': '♔',
'p': '♙',
'.': '·',
// ' ': ' '
};
print('');
final bordChars = pos.board.split('\n');
for (var i = 0; i < bordChars.length; i++) {
var row = bordChars[i];
if (!row.isSpace) {
var pieces = row.split('').map((e) => e = e.isSpace ? '' : uni_pieces[e]!);
print('${(10 - i)}${pieces.join(' ')}');
}
}
print(' a b c d e f g h \n\n');
}
}
class GameBot {
GameBot();
void gameMain() {
var hist = <Position>[
Position(initial, 0, [true, true], [true, true], 0, 0),
];
var searcher = Searcher();
while (true) {
UI.printBoard(hist.last);
if (hist.last.score <= -MATE_LOWER) {
print('You lost');
break;
}
// We query the user until she enters a (pseudo) legal move.
var move = <int>[];
final possibleMoves = hist.last.gen_moves().toList();
while (!possibleMoves.doContains(move)) {
var pattern = RegExp(
r'([a-h][1-8])' * 2,
caseSensitive: false,
multiLine: false,
);
print('Your move:');
var input = stdin.readLineSync();
var match = pattern.firstMatch(input.toString());
if (match != null) {
move = [UI.parse(match.group(1)), UI.parse(match.group(2))];
if (!possibleMoves.doContains(move)) {
print('Not valid move typed in. Try again');
}
} else {
// Inform the user when invalid input (e.g. "help") is entered
print('Please enter a move like g8f6');
}
}
try {
hist.add(hist.last.movePiece(move));
} catch (e) {
// print(e.toString());
}
// After our move we rotate the board and print it again.
// This allows us to see the effect of our move.
UI.printBoard(hist.last.rotate());
// print('${hist.last.score}');
if (hist.last.score <= -MATE_LOWER) {
print('You won');
break;
}
// Fire up the engine to look for a move.
var _depth = 0;
var score = 0;
var start = getSeconds();
/*
*/
for (var s in searcher.search(hist.last, hist.toSet())) {
_depth = s[0];
move = s[1];
score = s[2] ?? 0;
if (getSeconds() - start > 1) {
break;
}
}
if (score == MATE_UPPER) {
print('Checkmate!');
}
// The black player moves from a rotated position, so we have to
// 'back rotate' the move before printing it.
print('My move: ${UI.render(119 - move[0]) + UI.render(119 - move[1])}');
hist.add(hist.last.movePiece(move));
}
}
void playGame() {
dv.log('message');
setPst();
gameMain();
}
}

7
lib/index.dart Normal file
View File

@@ -0,0 +1,7 @@
export 'src/dartsunfish.dart';
export 'src/extentions.dart';
export 'src/globals.dart';
export 'src/helpers.dart';
export 'src/position.dart';
export 'src/searcher.dart';
export 'src/ui.dart';

86
lib/src/dartsunfish.dart Normal file
View File

@@ -0,0 +1,86 @@
import 'dart:io';
import 'package:dartsunfish/index.dart';
class GameBot {
GameBot();
void gameMain() {
var hist = <Position>[
Position(initial, 0, [true, true], [true, true], 0, 0),
];
var searcher = Searcher();
while (true) {
UI.printBoard(hist.last);
if (hist.last.score <= -MATE_LOWER) {
print('You lost');
break;
}
// We query the user until she enters a (pseudo) legal move.
var move = <int>[];
var score = 0;
final possibleMoves = hist.last.generateMoves().toList();
while (!possibleMoves.doContains(move)) {
var pattern = RegExp(
r'([a-h][1-8])' * 2,
caseSensitive: false,
multiLine: false,
);
print('Your move:');
var input = stdin.readLineSync();
var match = pattern.firstMatch(input.toString());
if (match != null) {
move = [UI.parse(match.group(1)), UI.parse(match.group(2))];
if (!possibleMoves.doContains(move)) {
print('Not valid move typed in. Try again');
}
} else {
// Inform the user when invalid input (e.g. "help") is entered
print('Please enter a move like g8f6');
}
}
try {
hist.add(hist.last.movePiece(move));
} catch (e) {
// print(e.toString());
}
// After our move we rotate the board and print it again.
// This allows us to see the effect of our move.
UI.printBoard(hist.last.rotate());
// print('${hist.last.score}');
if (hist.last.score <= -MATE_LOWER) {
print('You won');
break;
}
/*
*/
// Fire up the engine to look for a move.
// var _depth = 0;
var start = getSeconds();
for (var s in searcher.search(hist.last, hist.toSet())) {
// _depth = s[0];
move = s[0];
score = s[1] ?? 0;
if (getSeconds() - start > 1) {
break;
}
}
if (score == MATE_UPPER) {
print('Checkmate!');
}
// The black player moves from a rotated position, so we have to
// 'back rotate' the move before printing it.
print('My move: ${UI.render(119 - move[0]) + UI.render(119 - move[1])}');
hist.add(hist.last.movePiece(move));
}
}
void playGame() {
setPst();
gameMain();
}
}

81
lib/src/extentions.dart Normal file
View File

@@ -0,0 +1,81 @@
///String extentions
extension CheckString on String {
bool get isSpace => trim().isEmpty || RegExp(r'/\s/').hasMatch(this);
bool get isUpper => !isSpace && toUpperCase() == this && this != '.';
bool get isLower => !isSpace && toLowerCase() == this && this != '.';
String get reversed => split('').reversed.join('');
String get swapCase =>
split('').map((x) => x.toUpperCase() == x ? x.toLowerCase() : x.toUpperCase()).toList().join('');
String get reversedAndSwapCased =>
split('').map((x) => x.toUpperCase() == x ? x.toLowerCase() : x.toUpperCase()).toList().reversed.join('');
}
// List of list extention
extension CheckListOfTuples on List {
bool doContains(newList) => newList.length == 2 && indexWhere((l) => l[0] == newList[0] && l[1] == newList[1]) > -1;
}
extension CompareIretables<E> on Iterable<E> {
bool isEqual(Iterable newList) {
if (newList is! Iterable) return false;
if (newList.length != length || runtimeType != newList.runtimeType) {
return false;
}
for (var i = 0; i < length; i++) {
if (elementAt(i) is Iterable) {
print('In iterrable ${(elementAt(i) as Iterable).isEqual(newList.elementAt(i) as Iterable)}');
if ((elementAt(i) as Iterable).isEqual(newList.elementAt(i) as Iterable) == false) return false;
} else if (elementAt(i).runtimeType != newList.elementAt(i).runtimeType || elementAt(i) != newList.elementAt(i)) {
return false;
}
}
return true;
}
Iterable<T> mapIndexed<T>(T Function(E e, int i) f) {
var i = 0;
return map((e) => f(e, i++));
}
void forEachIndexed(void Function(E e, int i) f) {
var i = 0;
forEach((e) => f(e, i++));
}
}
extension XDartMap on Map {
T? get<T>(Object? key, {Object? or}) {
var tempMap = this;
var result = or;
if (key == null) {
return null;
} else {
for (final item in tempMap.keys) {
if (item.toString() == key.toString()) {
result = tempMap[item];
break;
}
}
if (result != null) {
return result as T;
} else {
return null;
}
}
}
bool isEqual(Map newMap) {
if (newMap is! Map) return false;
if (!keys.isEqual(newMap.keys)) return false;
for (var key in keys) {
if (this[key] is Iterable) {
if ((this[key] as Iterable).isEqual(newMap[key] as Iterable) == false) {
return false;
}
} else if (this[key] != newMap[key]) {
return false;
}
}
return true;
}
}

145
lib/src/globals.dart Normal file
View File

@@ -0,0 +1,145 @@
// //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// // Piece-Square tables. Tune these to change sunfish's behaviour
// //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/// TODO: add wizard
final piece = {'P': 100, 'N': 280, 'B': 320, 'R': 479, 'Q': 929, 'K': 60000};
///TODO: add 2 raws and 2 colums to each set AND Wizard pst
var pst = {
'P': [
0, 0, 0, 0, 0, 0, 0, 0, //
78, 83, 86, 73, 102, 82, 85, 90, //
7, 29, 21, 44, 40, 31, 44, 7, //
-17, 16, -2, 15, 14, 0, 15, -13, //
-26, 3, 10, 9, 6, 1, 0, -23, //
-22, 9, 5, -11, -10, -2, 3, -19, //
-31, 8, -7, -37, -36, -14, 3, -31, //
0, 0, 0, 0, 0, 0, 0, 0
], //
'N': [
-66, -53, -75, -75, -10, -55, -58, -70, //
-3, -6, 100, -36, 4, 62, -4, -14, //
10, 67, 1, 74, 73, 27, 62, -2, //
24, 24, 45, 37, 33, 41, 25, 17, //
-1, 5, 31, 21, 22, 35, 2, 0, //
-18, 10, 13, 22, 18, 15, 11, -14, //
-23, -15, 2, 0, 2, 0, -23, -20, //
-74, -23, -26, -24, -19, -35, -22, -69
], //
'B': [
-59, -78, -82, -76, -23, -107, -37, -50, //
-11, 20, 35, -42, -39, 31, 2, -22, //
-9, 39, -32, 41, 52, -10, 28, -14, //
25, 17, 20, 34, 26, 25, 15, 10, //
13, 10, 17, 23, 17, 16, 0, 7, //
14, 25, 24, 15, 8, 25, 20, 15, //
19, 20, 11, 6, 7, 6, 20, 16, //
-7, 2, -15, -12, -14, -15, -10, -10
], //
'R': [
35, 29, 33, 4, 37, 33, 56, 50, //
55, 29, 56, 67, 55, 62, 34, 60, //
19, 35, 28, 33, 45, 27, 25, 15, //
0, 5, 16, 13, 18, -4, -9, -6, //
-28, -35, -16, -21, -13, -29, -46, -30, //
-42, -28, -42, -25, -25, -35, -26, -46, //
-53, -38, -31, -26, -29, -43, -44, -53, //
-30, -24, -18, 5, -2, -18, -31, -32
], //
'Q': [
6, 1, -8, -104, 69, 24, 88, 26, //
14, 32, 60, -10, 20, 76, 57, 24, //
-2, 43, 32, 60, 72, 63, 43, 2, //
1, -16, 22, 17, 25, 20, -13, -6, //
-14, -15, -2, -5, -1, -10, -20, -22, //
-30, -6, -13, -11, -16, -11, -16, -27, //
-36, -18, 0, -19, -15, -15, -21, -38, //
-39, -30, -31, -13, -31, -36, -34, -42
], //
'K': [
4, 54, 47, -99, -99, 60, 83, -62, //
-32, 10, 55, 56, 56, 55, 10, 3, //
-62, 12, -57, 44, -67, 28, 37, -31, //
-55, 50, 11, -4, -19, 13, 0, -49, //
-55, -43, -52, -28, -51, -47, -8, -50, //
-47, -42, -43, -79, -64, -32, -29, -32, //
-4, 3, -14, -50, -57, -18, 13, 4, //
17, 30, -3, -14, 6, -1, 40, 18
], //
};
// recalculating Piece-Square raw into desk surrounded by 0-s
List<int> padrow(List<int> row, String k) {
var rowBody = <int>[for (int x in row) x + piece[k]!];
return [
0,
...rowBody,
0,
];
}
void setPst() {
pst.forEach((key, item) {
final innerItem = [...List.filled(20, 0)];
for (var i = 0; i < 8; i++) {
innerItem.addAll(padrow(item.getRange(i * 8, i * 8 + 8).toList(), key));
}
innerItem.addAll(List.filled(20, 0));
pst[key] = innerItem;
});
}
int getSeconds() {
return DateTime.now().millisecondsSinceEpoch ~/ 1000.toInt();
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Global constants
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Our board is represented as a 120 character string. The padding allows for
// fast detection of moves that don't stay within the board.
//TODO: Tune globals for 10x10 field
final A1 = 91, H1 = 98, A8 = 21, H8 = 28;
final initial = (' \n' // 0 - 9
' \n' // 10 - 19
' rnbqkbnr\n' // 20 - 29
' pppppppp\n' // 30 - 39
' ........\n' // 40 - 49
' ........\n' // 50 - 59
' ........\n' // 60 - 69
' ........\n' // 70 - 79
' PPPPPPPP\n' // 80 - 89
' RNBQKBNR\n' // 90 - 99
' \n' // 100 -109
' \n' // 110 -119
);
// Lists of possible moves for each piece type.
int N = -10, E = 1, S = 10, W = -1;
//TODO: add directions for Wizard
final Map<String?, List<int>> directions = {
'P': [N, N + N, N + W, N + E],
'N': [N + N + E, E + N + E, E + S + E, S + S + E, S + S + W, W + S + W, W + N + W, N + N + W],
'B': [N + E, S + E, S + W, N + W],
'R': [N, E, S, W],
'Q': [N, E, S, W, N + E, S + E, S + W, N + W],
'K': [N, E, S, W, N + E, S + E, S + W, N + W],
'.': []
};
// Mate value must be greater than 8*queen + 2*(rook+knight+bishop)
// King value is set to twice this value such that if the opponent is
// 8 queens up, but we got the king, we still exceed MATE_VALUE.
// When a MATE is detected, we'll set the score to MATE_UPPER - plies to get there
// E.g. Mate in 3 will be MATE_UPPER - 6
// TOD: replace mate with King capture event
final MATE_LOWER = piece['K']! - 10 * piece['Q']!;
final MATE_UPPER = piece['K']! + 10 * piece['Q']!;
// The table size is the maximum number of elements in the transposition table.
final TABLE_SIZE = 1e7;
// Constants for tuning search
final QS_LIMIT = 219, EVAL_ROUGHNESS = 13, DRAW_TEST = true;

29
lib/src/helpers.dart Normal file
View File

@@ -0,0 +1,29 @@
/// python counter immulation
Iterable<int> count(int firstval, int step) sync* {
var x = firstval;
while (true) {
yield (x);
x += step;
}
}
String reversed(String subject) {
return subject.split('').reversed.join();
}
String swapCase(String subject) {
if (subject is! String || subject.isEmpty) {
return '';
}
String _swap(String l) {
if (l.toUpperCase() == l) {
return l.toLowerCase();
} else {
return l.toUpperCase();
}
}
var subjectChars = subject.split('');
return subjectChars.map((x) => _swap(x)).join();
}

178
lib/src/position.dart Normal file
View File

@@ -0,0 +1,178 @@
import 'dart:math';
import 'package:dartsunfish/index.dart';
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Chess logic
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
class Position {
Position(
this.board,
this.score,
this.wc,
this.bc,
this.ep,
this.kp,
);
String board;
int score, ep, kp;
List<bool> wc, bc;
/*
""" A state of a chess game
board -- a 120 char representation of the board
score -- the board evaluation
wc -- the castling rights, [west/queen side, east/king side]
bc -- the opponent castling rights, [west/king side, east/queen side]
ep - the en passant square
kp - the king passant square
""";
*/
Iterable<List<int>> generateMoves() sync* {
// For each of our pieces, iterate through each possible 'ray' of moves,
// as defined in the 'directions' map. The rays are broken e.g. by
// captures or immediately in case of pieces such as knights.
/// TODO: add limitation of 3 cells for Wizard
// Split boadr string into list of chars
final charsList = board.split('');
// Iterate over list of chars
for (var i = 0; i < charsList.length; i++) {
final p = charsList[i];
if (!p.isUpper) {
continue;
}
for (var d in directions[p]!) {
for (var j in count(i + d, d)) {
final q = board[j];
// Stay inside the board, and off friendly pieces
if (q.isSpace || q.isUpper) {
break;
}
// Pawn move, double move and capture
if (p == 'P' && [N, N + N].contains(d) && q != '.') {
break;
}
if (p == 'P' && d == (N + N) && (i < A1 + N || board[i + N] != '.')) {
break;
}
if (p == 'P' && [N + W, N + E].contains(d) && q == '.' && ![ep, kp, kp - 1, kp + 1].contains(j)) {
break;
}
// Move it
final res = [i, j];
yield (res);
// Stop crawlers from sliding, and sliding after captures
if ('PNK'.contains(p) || q.isLower) {
break;
}
// Castling, by sliding the rook next to the king
if (i == A1 && board[j + E] == 'K' && wc[0]) {
yield ([j + E, j + W]);
}
if (i == H1 && board[j + W] == 'K' && wc[1]) {
yield ([j + W, j + E]);
}
}
}
}
}
Position rotate() {
''' Rotates the board, preserving enpassant ''';
return Position(board.reversedAndSwapCased, -score, bc, wc, ep > 0 ? 119 - ep : 0, kp > 0 ? 119 - kp : 0);
}
Position nullmove() {
''' Like rotate, but clears ep and kp ''';
return Position(board.reversedAndSwapCased, -score, bc, wc, 0, 0);
}
String put(String _str, int i, String p) {
final newStr = _str.substring(0, i) + p + _str.substring(i + 1);
return newStr;
}
// move piece due to the move scecification
Position movePiece(List<int> move) {
final i = move[0], j = move[1];
final p = board[i];
final q = board[j];
// Copy variables and reset ep and kp
var _board = board;
var _wc = wc, _bc = bc, _ep = 0, _kp = 0;
score = score + value(move);
// Actual move
board = put(_board, j, p);
board = put(board, i, '.');
// Castling rights, we move the rook or capture the opponent's
if (i == A1) {
_wc = [false, wc[1]];
}
if (i == H1) {
_wc = [wc[0], false];
}
if (j == A8) {
bc = [bc[0], false];
}
if (j == H8) {
bc = [false, bc[1]];
}
// Castling
if (p == 'K') {
_wc = [false, false];
if ((j - i).abs() == 2) {
kp = (i + j); //2
board = put(board, (j < i) ? A1 : H1, '.');
board = put(board, kp, 'R');
}
}
// Pawn promotion, double move and en passant capture
if (p == 'P') {
if (A8 <= j && j <= H8) {
board = put(board, j, 'Q');
}
if (j - i == 2 * N) {
ep = i + N;
}
if (j == ep) {
board = put(board, j + S, '.');
}
}
// We rotate the returned position, so it's ready for the next player
return Position(board, score, _wc, _bc, _ep, _kp).rotate();
}
// calculate score of the board position
int value(List<int> move) {
final i = move[0], j = move[1];
final p = board[i], q = board[j];
// Actual move
score = pst[p] != null ? pst[p]![j] - pst[p]![i] : 0;
// Capture
if (!q.isUpper) {
score += pst[q.toUpperCase()] != null ? pst[q.toUpperCase()]![119 - j] : 0;
}
// Castling check detection
if ((j - kp).abs() < 2) {
score += pst['K']![119 - j];
}
// Castling
if (p == 'K' && (i - j).abs() == 2) {
score += pst['R']![(i + j)]; //2]
score -= pst['R']![j < i ? A1 : H1];
}
// Special pawn stuff
if (p == 'P') {
if (A8 <= j && j <= H8) {
score += pst['Q']![j] - pst['P']![j];
}
if (j == ep) {
score += pst['P']![119 - (j + S)];
}
}
return score;
}
}

220
lib/src/searcher.dart Normal file
View File

@@ -0,0 +1,220 @@
import 'dart:io';
import 'dart:math';
import 'package:dartsunfish/index.dart';
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Search logic
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// lower <= s(pos) <= upper
class Entry {
Entry(this.lower, this.upper);
int lower;
int upper;
}
class Searcher {
Searcher();
late Map<Set, Entry> tpScore = {};
late Map<Position, List<int>?> tpMove = {};
late Set<Position> history = <Position>{};
int nodes = 0;
int bound(Position pos, int gamma, int depth, {bool root = true}) {
''' returns r where
s(pos) <= r < gamma if gamma > s(pos)
gamma <= r <= s(pos) if gamma <= s(pos)''';
nodes += 1;
// Depth <= 0 is QSearch. Here any position is searched as deeply as is needed for
// calmness, and from this point on there is no difference in behaviour depending on
// depth, so so there is no reason to keep different depths in the transposition table.
depth = max(depth, 0);
// Sunfish is a king-capture engine, so we should always check if we
// still have a king. Notice since this is the only termination check,
// the remaining code has to be comfortable with being mated, stalemated
// or able to capture the opponent king.
if (pos.score <= -MATE_LOWER) {
return -MATE_UPPER;
}
// We detect 3-fold captures by comparing against previously
// _actually played_ positions.
// Note that we need to do this before we look in the table, as the
// position may have been previously reached with a different score.
// This is what prevents a search instability.
// FIXME: This is not true, since other positions will be affected by
// the new values for all the drawn positions.
if (DRAW_TEST) {
// print('Nit root ${!root} * ${history.contains(pos)} ${pos.score}');
if (history.contains(pos) && !root) {
return 0;
}
}
// Look in the table if we have already searched this position before.
// We also need to be sure, that the stored search was over the same
// nodes as the current search.
var entry = tpScore.get<Entry>({pos, depth, root}, or: Entry(-MATE_UPPER, MATE_UPPER)); // as Entry;
if (entry!.lower >= gamma && (!root || tpMove.get<List<int>>(pos, or: <int>[])!.isNotEmpty)) {
return entry.lower;
}
if (entry.upper < gamma) {
return entry.upper;
}
// Here extensions may be added
// Such as 'if in_check: depth += 1'
// Generator of moves to search in order.
// This allows us to define the moves, but only calculate them if needed.
Iterable<List<dynamic>> moves() sync* {
// First try not moving at all. We only do this if there is at least one major
// piece left on the board, since otherwise zugzwangs are too dangerous.
// if (depth > 0 && !root && any(c in pos.board for c in 'RBNQ')){
if (depth > 0 && !root && pos.board.split('').any((c) => 'RBNQ'.contains(c))) {
// print('Bound in moves1');
yield ([null, -bound(pos.nullmove(), 1 - gamma, depth - 3, root: false)]);
}
// For QSearch we have a different kind of null-move, namely we can just stop
// and not capture anything else.
if (depth == 0) {
yield ([null, pos.score]);
}
// Then killer move. We search it twice, but the tp will fix things for us.
// Note, we don't have to check for legality, since we've already done it
// before. Also note that in QS the killer must be a capture, otherwise we
// will be non deterministic.
var killer = tpMove.get<List<int>>(pos, or: <int>[]);
if (killer!.isNotEmpty && (depth > 0 || pos.value(killer) >= QS_LIMIT)) {
// print('Bound in moves2 killer');
yield ([killer, -bound(pos.movePiece(killer), 1 - gamma, depth - 1, root: false)]);
}
// Then all the other moves
var possibleMoves = pos.generateMoves().toList()
..sort((a, b) => pos.value(a).compareTo(pos.value(b)))
..toList(); //.reversed;
for (var move in possibleMoves.reversed) {
//pos.generateMoves().toList().sort((a, b) => a.value.compareto(b.value)).toList().reversed)) {
// for val, move in sorted(((pos.value(move), move) for move in pos.generateMoves()), reverse=true):
// If depth == 0 we only try moves with high intrinsic score (captures and
// promotions). Otherwise we do all moves.
if (depth > 0 || pos.value(move) >= QS_LIMIT) {
// print('Bound in moves3');
yield ([move, -bound(pos.movePiece(move), 1 - gamma, depth - 1, root: false)]);
}
}
}
// Run through the moves, shortcutting when possible
var best = -MATE_UPPER;
for (var m in moves()) {
List<int>? move = m[0];
int score = m[1];
best = max(best, score);
// if (depth == 0){
// }
if (best >= gamma) {
// Clear before setting, so we always have a value
if (tpMove.length > TABLE_SIZE) {
tpMove.clear();
}
// Save the move for pv construction and killer heuristic
tpMove[pos] = move;
// print([
// 'Depth',
// depth,
// 'Move',
// move != null ? UI.render(119 - move[0]) + UI.render(119 - move[1]) : 'No move',
// 'Score',
// score,
// 'Best',
// best,
// 'Gamma',
// gamma,
// 'STOP',
// best >= gamma
// ]);
break;
}
}
// Stalemate checking is a bit tricky: Say we failed low, because
// we can't (legally) move and so the (real) score is -infty.
// At the next depth we are allowed to just return r, -infty <= r < gamma,
// which is normally fine.
// However, what if gamma = -10 and we don't have any legal moves?
// Then the score is actaully a draw and we should fail high!
// Thus, if best < gamma and best < 0 we need to double check what we are doing.
// This doesn't prevent sunfish from making a move that results in stalemate,
// but only if depth == 1, so that's probably fair enough.
// (Btw, at depth 1 we can also mate without realizing.)
if (best < gamma && best < 0 && depth > 0) {
bool is_dead(Position pos) {
return pos.generateMoves().any((m) => pos.value(m) >= MATE_LOWER);
}
// if (all(is_dead(pos.move(m)) for m in pos.generateMoves())){
if (pos.generateMoves().every((m) => is_dead(pos.movePiece(m)))) {
var in_check = is_dead(pos.nullmove());
best = in_check ? -MATE_UPPER : 0;
}
}
// Clear before setting, so we always have a value
if (tpScore.length > TABLE_SIZE) {
tpScore.clear();
}
// Table part 2
if (best >= gamma) {
tpScore[{pos, depth, root}] = Entry(best, entry.upper);
}
if (best < gamma) {
tpScore[{pos, depth, root}] = Entry(entry.lower, best);
}
return best;
}
Iterable<dynamic> search(Position pos, Set<Position> _history) sync* {
''' Iterative deepening MTD-bi search ''';
nodes = 0;
if (DRAW_TEST) {
history = _history;
// Clearing table due to new history
tpScore.clear();
}
// In finished games, we could potentially go far enough to cause a recursion
// limit exception. Hence we bound the ply.
for (var depth = 1; depth < 100; depth++) {
// The inner loop is a binary search on the score of the position.
// Inv: lower <= score <= upper
// 'while lower != upper' would work, but play tests show a margin of 20 plays
// better.
var lower = -MATE_UPPER;
var upper = MATE_UPPER;
/*
*/
while (lower < upper - EVAL_ROUGHNESS) {
var gamma = (lower + upper + 1) ~/ 2;
// print([lower, upper, gamma, lower < upper - EVAL_ROUGHNESS]);
var score = bound(pos, gamma, depth);
print('Call in while');
if (score >= gamma) lower = score;
if (score < gamma) upper = score;
}
// We want to make sure the move to play hasn't been kicked out of the table,
// So we make another call that must always fail high and thus produce a move.
bound(pos, lower, depth);
print('Call finally');
// If the game hasn't finished we can retrieve our move from the
// transposition table.
yield ([
// depth,
tpMove.get<List<int>>(pos),
tpScore.get<Entry>({pos, depth, true})?.lower
]);
}
}
}

50
lib/src/ui.dart Normal file
View File

@@ -0,0 +1,50 @@
import 'package:dartsunfish/index.dart';
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// User interface
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
class UI {
static int parse(String? c) {
var fil = c![0].codeUnits.first - 'a'.codeUnits.first;
var rank = int.parse(c[1]) - 1;
return A1 + fil - 10 * rank;
}
static String render(int i) {
var rank = (i - A1) ~/ 10;
var fil = (i - A1) % 10;
return String.fromCharCodes([fil + 'a'.codeUnits.first]) + (-rank + 1).toString();
}
static void printBoard(Position pos) {
final uni_pieces = {
'R': '♜',
'N': '♞',
'B': '♝',
'Q': '♛',
'K': '♚',
'P': '♟',
'r': '♖',
'n': '♘',
'b': '♗',
'q': '♕',
'k': '♔',
'p': '♙',
'.': '·',
};
print('');
final bordRows = pos.board.split('\n');
for (var i = 0; i < bordRows.length; i++) {
var row = bordRows[i].split('');
var pieces = row.map((e) => e.isSpace ? '' : uni_pieces.get(e, or: e));
if (!row.every((element) => element.isSpace)) {
print('${(10 - i)}${pieces.join(' ')}');
}
}
print(' a b c d e f g h');
print(' \n\n');
}
// for i, row in enumerate(pos.board.split()):
// print(' ', 8-i, ' '.join(uni_pieces.get(p, p) for p in row))
}

132
lib/tester.dart Normal file
View File

@@ -0,0 +1,132 @@
import 'dart:convert';
import 'package:dartsunfish/src/extentions.dart';
class MyItem {
int id;
String name;
MyItem({
required this.id,
required this.name,
});
MyItem copyWith({
int? id,
String? name,
}) {
return MyItem(
id: id ?? this.id,
name: name ?? this.name,
);
}
Map<String, dynamic> toMap() {
return {
'id': id,
'name': name,
};
}
factory MyItem.fromMap(Map<String, dynamic> map) {
return MyItem(
id: map['id'],
name: map['name'],
);
}
String toJson() => json.encode(toMap());
factory MyItem.fromJson(String source) => MyItem.fromMap(json.decode(source));
@override
String toString() => 'MyItem(id: $id, name: $name)';
@override
bool operator ==(Object other) {
if (identical(this, other)) return true;
return other is MyItem && other.id == id && other.name == name;
}
@override
int get hashCode => id.hashCode ^ name.hashCode;
}
void main(List<String> args) {
final someList = List.generate(
10,
(i) => {
{i, 's'}: 'See item $i'
});
bool root = true;
final someSet = Set.from(List<MyItem>.generate(10, (index) => MyItem(id: index, name: 'name $index')).toSet());
print(someSet.contains(MyItem(id: 2, name: 'name 2')) && !root);
print(someList);
final first = someList[0].get({0, 's'});
print('I found $first');
final someMap = {
{1, 'S1'}: 'See item 1',
{2, 'S2'}: 'See item 1'
};
var s1 = {
1,
'S1',
22.23,
['q', 12]
};
var s2 = {
1,
'S1',
22.23,
['q', 12]
};
var s3 = {
1: 'S1',
22.23: ['q', 12]
};
var s4 = {
1: 'S1',
22.23: ['q', 12]
};
print('Equality test gives ${s1.isEqual(s2)}');
print('Equality test gives ${s3.isEqual(s4)}');
print(someMap.get({1, 'S2'}, or: 'Oops'));
var ff = someList.firstWhere((element) => element.get({1, 's'}) != null, orElse: () => someList[0]);
// print('In map ${someMap.entries.toList()}');
print('In map $ff');
for (var i in List.generate(10, (index) => index + 1)) {
print('III = $i');
}
Iterator<String> getStringIterator(String s) => s.runes.map((r) => String.fromCharCode(r)).iterator;
final str = 'Hello, World';
final strList = str.split('');
strList.forEachIndexed((e, i) {
if (e != 'o') {
print('See $e');
} else {
return;
}
});
final strIter = getStringIterator(str);
for (var i = 0; i < str.runes.length; i++) {
strIter.moveNext();
print('In map ${strIter.current}');
print('And ${String.fromCharCode(str.runes.elementAt(i))}');
}
}

7
pubspec.lock
View File

@@ -78,6 +78,13 @@ packages:
url: "https://pub.dartlang.org" url: "https://pub.dartlang.org"
source: hosted source: hosted
version: "3.0.1" version: "3.0.1"
equatable:
dependency: "direct main"
description:
name: equatable
url: "https://pub.dartlang.org"
source: hosted
version: "2.0.3"
file: file:
dependency: transitive dependency: transitive
description: description:

3
pubspec.yaml
View File

@@ -7,10 +7,9 @@ environment:
sdk: '>=2.12.0 <3.0.0' sdk: '>=2.12.0 <3.0.0'
dependencies: dependencies:
# path: ^1.8.0
# flutter: # flutter:
# sdk: flutter # sdk: flutter
equatable: 2.0.3
dev_dependencies: dev_dependencies:
pedantic: ^1.10.0 pedantic: ^1.10.0
test: ^1.16.0 test: ^1.16.0

481
python/sunfish.py Normal file
View File

@@ -0,0 +1,481 @@
#!/usr/bin/env pypy
# -*- coding: utf-8 -*-
from __future__ import print_function
import re
import sys
import time
from itertools import count
from collections import namedtuple
###############################################################################
# Piece-Square tables. Tune these to change sunfish's behaviour
###############################################################################
piece = {'P': 100, 'N': 280, 'B': 320, 'R': 479, 'Q': 929, 'K': 60000}
pst = {
'P': (0, 0, 0, 0, 0, 0, 0, 0,
78, 83, 86, 73, 102, 82, 85, 90,
7, 29, 21, 44, 40, 31, 44, 7,
-17, 16, -2, 15, 14, 0, 15, -13,
-26, 3, 10, 9, 6, 1, 0, -23,
-22, 9, 5, -11, -10, -2, 3, -19,
-31, 8, -7, -37, -36, -14, 3, -31,
0, 0, 0, 0, 0, 0, 0, 0),
'N': (-66, -53, -75, -75, -10, -55, -58, -70,
-3, -6, 100, -36, 4, 62, -4, -14,
10, 67, 1, 74, 73, 27, 62, -2,
24, 24, 45, 37, 33, 41, 25, 17,
-1, 5, 31, 21, 22, 35, 2, 0,
-18, 10, 13, 22, 18, 15, 11, -14,
-23, -15, 2, 0, 2, 0, -23, -20,
-74, -23, -26, -24, -19, -35, -22, -69),
'B': (-59, -78, -82, -76, -23, -107, -37, -50,
-11, 20, 35, -42, -39, 31, 2, -22,
-9, 39, -32, 41, 52, -10, 28, -14,
25, 17, 20, 34, 26, 25, 15, 10,
13, 10, 17, 23, 17, 16, 0, 7,
14, 25, 24, 15, 8, 25, 20, 15,
19, 20, 11, 6, 7, 6, 20, 16,
-7, 2, -15, -12, -14, -15, -10, -10),
'R': (35, 29, 33, 4, 37, 33, 56, 50,
55, 29, 56, 67, 55, 62, 34, 60,
19, 35, 28, 33, 45, 27, 25, 15,
0, 5, 16, 13, 18, -4, -9, -6,
-28, -35, -16, -21, -13, -29, -46, -30,
-42, -28, -42, -25, -25, -35, -26, -46,
-53, -38, -31, -26, -29, -43, -44, -53,
-30, -24, -18, 5, -2, -18, -31, -32),
'Q': (6, 1, -8, -104, 69, 24, 88, 26,
14, 32, 60, -10, 20, 76, 57, 24,
-2, 43, 32, 60, 72, 63, 43, 2,
1, -16, 22, 17, 25, 20, -13, -6,
-14, -15, -2, -5, -1, -10, -20, -22,
-30, -6, -13, -11, -16, -11, -16, -27,
-36, -18, 0, -19, -15, -15, -21, -38,
-39, -30, -31, -13, -31, -36, -34, -42),
'K': (4, 54, 47, -99, -99, 60, 83, -62,
-32, 10, 55, 56, 56, 55, 10, 3,
-62, 12, -57, 44, -67, 28, 37, -31,
-55, 50, 11, -4, -19, 13, 0, -49,
-55, -43, -52, -28, -51, -47, -8, -50,
-47, -42, -43, -79, -64, -32, -29, -32,
-4, 3, -14, -50, -57, -18, 13, 4,
17, 30, -3, -14, 6, -1, 40, 18),
}
# Pad tables and join piece and pst dictionaries
for k, table in pst.items():
def padrow(row): return (0,) + tuple(x+piece[k] for x in row) + (0,)
pst[k] = sum((padrow(table[i*8:i*8+8]) for i in range(8)), ())
pst[k] = (0,)*20 + pst[k] + (0,)*20
###############################################################################
# Global constants
###############################################################################
# Our board is represented as a 120 character string. The padding allows for
# fast detection of moves that don't stay within the board.
A1, H1, A8, H8 = 91, 98, 21, 28
initial = (
' \n' # 0 - 9
' \n' # 10 - 19
' rnbqkbnr\n' # 20 - 29
' pppppppp\n' # 30 - 39
' ........\n' # 40 - 49
' ........\n' # 50 - 59
' ........\n' # 60 - 69
' ........\n' # 70 - 79
' PPPPPPPP\n' # 80 - 89
' RNBQKBNR\n' # 90 - 99
' \n' # 100 -109
' \n' # 110 -119
)
# Lists of possible moves for each piece type.
N, E, S, W = -10, 1, 10, -1
directions = {
'P': (N, N+N, N+W, N+E),
'N': (N+N+E, E+N+E, E+S+E, S+S+E, S+S+W, W+S+W, W+N+W, N+N+W),
'B': (N+E, S+E, S+W, N+W),
'R': (N, E, S, W),
'Q': (N, E, S, W, N+E, S+E, S+W, N+W),
'K': (N, E, S, W, N+E, S+E, S+W, N+W)
}
# Mate value must be greater than 8*queen + 2*(rook+knight+bishop)
# King value is set to twice this value such that if the opponent is
# 8 queens up, but we got the king, we still exceed MATE_VALUE.
# When a MATE is detected, we'll set the score to - plies to get there
# E.g. Mate in 3 will be MATE_UPPER - 6
MATE_LOWER = piece['K'] - 10*piece['Q']
MATE_UPPER = piece['K'] + 10*piece['Q']
# The table size is the maximum number of elements in the transposition table.
TABLE_SIZE = 1e7
# Constants for tuning search
QS_LIMIT = 219
EVAL_ROUGHNESS = 13
DRAW_TEST = True
###############################################################################
# Chess logic
###############################################################################
class Position(namedtuple('Position', 'board score wc bc ep kp')):
""" A state of a chess game
board -- a 120 char representation of the board
score -- the board evaluation
wc -- the castling rights, [west/queen side, east/king side]
bc -- the opponent castling rights, [west/king side, east/queen side]
ep - the en passant square
kp - the king passant square
"""
def gen_moves(self):
# For each of our pieces, iterate through each possible 'ray' of moves,
# as defined in the 'directions' map. The rays are broken e.g. by
# captures or immediately in case of pieces such as knights.
for i, p in enumerate(self.board):
if not p.isupper():
continue
for d in directions[p]:
for j in count(i+d, d):
q = self.board[j]
# Stay inside the board, and off friendly pieces
if q.isspace() or q.isupper():
break
# Pawn move, double move and capture
if p == 'P' and d in (N, N+N) and q != '.':
break
if p == 'P' and d == N+N and (i < A1+N or self.board[i+N] != '.'):
break
if p == 'P' and d in (N+W, N+E) and q == '.' \
and j not in (self.ep, self.kp, self.kp-1, self.kp+1):
break
# Move it
yield (i, j)
# Stop crawlers from sliding, and sliding after captures
if p in 'PNK' or q.islower():
break
# Castling, by sliding the rook next to the king
if i == A1 and self.board[j+E] == 'K' and self.wc[0]:
yield (j+E, j+W)
if i == H1 and self.board[j+W] == 'K' and self.wc[1]:
yield (j+W, j+E)
def rotate(self):
''' Rotates the board, preserving enpassant '''
return Position(
self.board[::-1].swapcase(), -self.score, self.bc, self.wc,
119-self.ep if self.ep else 0,
119-self.kp if self.kp else 0)
def nullmove(self):
''' Like rotate, but clears ep and kp '''
return Position(
self.board[::-1].swapcase(), -self.score,
self.bc, self.wc, 0, 0)
def move(self, move):
i, j = move
p, q = self.board[i], self.board[j]
def put(board, i, p): return board[:i] + p + board[i+1:]
# Copy variables and reset ep and kp
board = self.board
wc, bc, ep, kp = self.wc, self.bc, 0, 0
score = self.score + self.value(move)
# Actual move
board = put(board, j, board[i])
board = put(board, i, '.')
# Castling rights, we move the rook or capture the opponent's
if i == A1:
wc = (False, wc[1])
if i == H1:
wc = (wc[0], False)
if j == A8:
bc = (bc[0], False)
if j == H8:
bc = (False, bc[1])
# Castling
if p == 'K':
wc = (False, False)
if abs(j-i) == 2:
kp = (i+j)//2
board = put(board, A1 if j < i else H1, '.')
board = put(board, kp, 'R')
# Pawn promotion, double move and en passant capture
if p == 'P':
if A8 <= j <= H8:
board = put(board, j, 'Q')
if j - i == 2*N:
ep = i + N
if j == self.ep:
board = put(board, j+S, '.')
# We rotate the returned position, so it's ready for the next player
return Position(board, score, wc, bc, ep, kp).rotate()
def value(self, move):
i, j = move
p, q = self.board[i], self.board[j]
# Actual move
score = pst[p][j] - pst[p][i]
# Capture
if q.islower():
score += pst[q.upper()][119-j]
# Castling check detection
if abs(j-self.kp) < 2:
score += pst['K'][119-j]
# Castling
if p == 'K' and abs(i-j) == 2:
score += pst['R'][(i+j)//2]
score -= pst['R'][A1 if j < i else H1]
# Special pawn stuff
if p == 'P':
if A8 <= j <= H8:
score += pst['Q'][j] - pst['P'][j]
if j == self.ep:
score += pst['P'][119-(j+S)]
return score
###############################################################################
# Search logic
###############################################################################
# lower <= s(pos) <= upper
Entry = namedtuple('Entry', 'lower upper')
class Searcher:
def __init__(self):
self.tp_score = {}
self.tp_move = {}
self.history = set()
self.nodes = 0
def bound(self, pos, gamma, depth, root=True):
""" returns r where
s(pos) <= r < gamma if gamma > s(pos)
gamma <= r <= s(pos) if gamma <= s(pos)"""
self.nodes += 1
# Depth <= 0 is QSearch. Here any position is searched as deeply as is needed for
# calmness, and from this point on there is no difference in behaviour depending on
# depth, so so there is no reason to keep different depths in the transposition table.
depth = max(depth, 0)
# Sunfish is a king-capture engine, so we should always check if we
# still have a king. Notice since this is the only termination check,
# the remaining code has to be comfortable with being mated, stalemated
# or able to capture the opponent king.
if pos.score <= -MATE_LOWER:
return -MATE_UPPER
# We detect 3-fold captures by comparing against previously
# _actually played_ positions.
# Note that we need to do this before we look in the table, as the
# position may have been previously reached with a different score.
# This is what prevents a search instability.
# FIXME: This is not true, since other positions will be affected by
# the new values for all the drawn positions.
if DRAW_TEST:
if not root and pos in self.history:
print('Nit root', not root, 'or in history',
pos in self.history, pos.score)
return 0
# Look in the table if we have already searched this position before.
# We also need to be sure, that the stored search was over the same
# nodes as the current search.
entry = self.tp_score.get(
(pos, depth, root), Entry(-MATE_UPPER, MATE_UPPER))
if entry.lower >= gamma and (not root or self.tp_move.get(pos) is not None):
return entry.lower
if entry.upper < gamma:
return entry.upper
# Here extensions may be added
# Such as 'if in_check: depth += 1'
# Generator of moves to search in order.
# This allows us to define the moves, but only calculate them if needed.
def moves():
# First try not moving at all. We only do this if there is at least one major
# piece left on the board, since otherwise zugzwangs are too dangerous.
if depth > 0 and not root and any(c in pos.board for c in 'RBNQ'):
# print('Bound in moves1 RBNQ')
yield None, -self.bound(pos.nullmove(), 1-gamma, depth-3, root=False)
# For QSearch we have a different kind of null-move, namely we can just stop
# and not capture anything else.
if depth == 0:
yield None, pos.score
# Then killer move. We search it twice, but the tp will fix things for us.
# Note, we don't have to check for legality, since we've already done it
# before. Also note that in QS the killer must be a capture, otherwise we
# will be non deterministic.
killer = self.tp_move.get(pos)
if killer and (depth > 0 or pos.value(killer) >= QS_LIMIT):
# print('Bound in moves2 killer')
yield killer, -self.bound(pos.move(killer), 1-gamma, depth-1, root=False)
# Then all the other moves
for move in sorted(pos.gen_moves(), key=pos.value, reverse=True):
# for val, move in sorted(((pos.value(move), move) for move in pos.gen_moves()), reverse=True):
# If depth == 0 we only try moves with high intrinsic score (captures and
# promotions). Otherwise we do all moves.
if depth > 0 or pos.value(move) >= QS_LIMIT:
# print('Bound in moves3')
yield move, -self.bound(pos.move(move), 1-gamma, depth-1, root=False)
# Run through the moves, shortcutting when possible
best = -MATE_UPPER
for move, score in moves():
best = max(best, score)
if best >= gamma:
# Clear before setting, so we always have a value
if len(self.tp_move) > TABLE_SIZE:
self.tp_move.clear()
# Save the move for pv construction and killer heuristic
self.tp_move[pos] = move
break
# Stalemate checking is a bit tricky: Say we failed low, because
# we can't (legally) move and so the (real) score is -infty.
# At the next depth we are allowed to just return r, -infty <= r < gamma,
# which is normally fine.
# However, what if gamma = -10 and we don't have any legal moves?
# Then the score is actaully a draw and we should fail high!
# Thus, if best < gamma and best < 0 we need to double check what we are doing.
# This doesn't prevent sunfish from making a move that results in stalemate,
# but only if depth == 1, so that's probably fair enough.
# (Btw, at depth 1 we can also mate without realizing.)
if best < gamma and best < 0 and depth > 0:
def is_dead(pos): return any(pos.value(m) >=
MATE_LOWER for m in pos.gen_moves())
if all(is_dead(pos.move(m)) for m in pos.gen_moves()):
in_check = is_dead(pos.nullmove())
best = -MATE_UPPER if in_check else 0
# Clear before setting, so we always have a value
if len(self.tp_score) > TABLE_SIZE:
self.tp_score.clear()
# Table part 2
if best >= gamma:
self.tp_score[pos, depth, root] = Entry(best, entry.upper)
if best < gamma:
self.tp_score[pos, depth, root] = Entry(entry.lower, best)
return best
def search(self, pos, history=()):
""" Iterative deepening MTD-bi search """
self.nodes = 0
if DRAW_TEST:
self.history = set(history)
# print('# Clearing table due to new history')
self.tp_score.clear()
# In finished games, we could potentially go far enough to cause a recursion
# limit exception. Hence we bound the ply.
for depth in range(1, 1000):
# The inner loop is a binary search on the score of the position.
# Inv: lower <= score <= upper
# 'while lower != upper' would work, but play tests show a margin of 20 plays
# better.
lower, upper = -MATE_UPPER, MATE_UPPER
while lower < upper - EVAL_ROUGHNESS:
gamma = (lower+upper+1)//2
# print(lower, upper, gamma, lower < upper - EVAL_ROUGHNESS)
score = self.bound(pos, gamma, depth)
print('Call bounder in while', score)
if score >= gamma:
lower = score
if score < gamma:
upper = score
# We want to make sure the move to play hasn't been kicked out of the table,
# So we make another call that must always fail high and thus produce a move.
self.bound(pos, lower, depth)
print('Call bounder final', score)
# If the game hasn't finished we can retrieve our move from the
# transposition table.
yield depth, self.tp_move.get(pos), self.tp_score.get((pos, depth, True)).lower
###############################################################################
# User interface
###############################################################################
# Python 2 compatability
if sys.version_info[0] == 2:
input = raw_input
def parse(c):
fil, rank = ord(c[0]) - ord('a'), int(c[1]) - 1
return A1 + fil - 10*rank
def render(i):
rank, fil = divmod(i - A1, 10)
return chr(fil + ord('a')) + str(-rank + 1)
def print_pos(pos):
print()
uni_pieces = {'R': '♜', 'N': '♞', 'B': '♝', 'Q': '♛', 'K': '♚', 'P': '♟',
'r': '♖', 'n': '♘', 'b': '♗', 'q': '♕', 'k': '♔', 'p': '♙', '.': '·'}
for i, row in enumerate(pos.board.split()):
print(' ', 8-i, ' '.join(uni_pieces.get(p, p) for p in row))
print(' a b c d e f g h \n\n')
def main():
hist = [Position(initial, 0, (True, True), (True, True), 0, 0)]
searcher = Searcher()
while True:
print_pos(hist[-1])
if hist[-1].score <= -MATE_LOWER:
print("You lost")
break
# We query the user until she enters a (pseudo) legal move.
move = None
while move not in hist[-1].gen_moves():
match = re.match('([a-h][1-8])'*2, input('Your move: '))
if match:
move = parse(match.group(1)), parse(match.group(2))
else:
# Inform the user when invalid input (e.g. "help") is entered
print("Please enter a move like g8f6")
hist.append(hist[-1].move(move))
print(hist[-1].score)
# After our move we rotate the board and print it again.
# This allows us to see the effect of our move.
print_pos(hist[-1].rotate())
if hist[-1].score <= -MATE_LOWER:
print("You won")
break
# Fire up the engine to look for a move.
start = time.time()
for _depth, move, score in searcher.search(hist[-1], hist):
if time.time() - start > 1:
break
if score == MATE_UPPER:
print("Checkmate!")
# The black player moves from a rotated position, so we have to
# 'back rotate' the move before printing it.
print("My move:", render(119-move[0]) + render(119-move[1]), score)
hist.append(hist[-1].move(move))
if __name__ == '__main__':
main()