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Prioritize computing nodes with few children, prioritize takes, move 1 second earlier to avoid exceeding the move time

master
Dany Thach 2025-02-27 22:42:04 +01:00
parent 943aab1a14
commit 00f371b913
3 changed files with 30 additions and 15 deletions
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15
lib/classes/best_move_searcher.dart
View File

@ -98,10 +98,15 @@ class BestMoveSearcher {
return value;
}
static int getPositionBasePriority(Position position, int value, Iterable<(String, Position)> legalMoves, int depth) =>
legalMoves.isEmpty
? Numbers.maxInteger
: 0;
static int getPositionBasePriority(Position position, int value, Iterable<(String, Position)> legalMoves, int depth) {
if (legalMoves.isEmpty) {
return Numbers.maxInteger;
}
if (legalMoves.length < 10) {
return (-2520 / legalMoves.length).toInt() >> 2;
}
return 0;
}
Future<String?> search(Position position, int? moveTime) async {
_isRunning = true;
@ -114,7 +119,7 @@ class BestMoveSearcher {
while (!_isStopped && positionTree.priority < Numbers.maxInteger) {
positionTree.computeStep();
time = DateTime.now().millisecondsSinceEpoch - startTime;
if (null != moveTime && time >= moveTime) {
if (null != moveTime && time >= moveTime - 1000) {
_isStopped = true;
}
if (positionTree.childrenByValue.isNotEmpty || bestValue != positionTree.value) {

7
lib/classes/position.dart
View File

@ -363,4 +363,11 @@ class Position {
move.length > 4 ? move.substring(4).toLowerCase() : null,
);
static bool isTake(Position position, String move) {
final (int from, int to, String? promotingPiece) = moveStringToIndices(move);
return
(position.board[to] != Piece.emptySquare) ||
(position.enPassantTargetSquare == to && (position.board[from] == Piece.whitePawn || position.board[from] == Piece.blackPawn));
}
}

23
lib/data_structures/position_tree_node.dart
View File

@ -63,27 +63,30 @@ class PositionTreeNode {
_computeChildren();
return;
}
final PositionTreeNode firstChild = children.first;
final int initialFirstChildNodeCount = firstChild.nodeCount;
firstChild.computeStep();
children.updateElement(firstChild.move);
childrenByValue.updateElement(firstChild.move);
nodeCount += firstChild.nodeCount - initialFirstChildNodeCount;
if (firstChild.depth + 1 > depth) {
depth = firstChild.depth + 1;
final PositionTreeNode computedChild = children.first;
final int initialFirstChildNodeCount = computedChild.nodeCount;
computedChild.computeStep();
children.updateElement(computedChild.move);
childrenByValue.updateElement(computedChild.move);
nodeCount += computedChild.nodeCount - initialFirstChildNodeCount;
if (computedChild.depth + 1 > depth) {
depth = computedChild.depth + 1;
}
priority = (children.first.priority == Numbers.maxInteger) ? children.first.priority : children.first.priority + 1;
priority = (children.first.priority == Numbers.maxInteger) ? children.first.priority : children.first.priority + 100;
value = childrenByValue.first.value;
}
void _computeChildren() {
for (final (String, Position) move in legalMoves) {
final PositionTreeNode positionTreeNode = PositionTreeNode.fromPosition(move.$2, move.$1);
if (Position.isTake(position, move.$1)) {
positionTreeNode.priority -= 200;
}
children.add(positionTreeNode);
childrenByValue.add(positionTreeNode);
}
nodeCount = legalMoves.length;
priority = (children.first.priority == Numbers.maxInteger) ? children.first.priority : children.first.priority + 1;
priority = (children.first.priority == Numbers.maxInteger) ? children.first.priority : children.first.priority + 100;
depth = 1;
value = childrenByValue.first.value;
}