Class DepthFirstNode<P extends IGamePosition<P>>

java.lang.Object

gametree.GameTreeNode<DepthFirstNode<P>, P>

gametree.DepthFirstNode<P>

Type Parameters:

P - The game position to store in this DepthFirstNode.

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

DepthFirstNode.RootDFNode

public class DepthFirstNode<P extends IGamePosition<P>>
extends GameTreeNode<DepthFirstNode<P>, P>

GameTreeNode implementation that does not store children nodes, but does store the depth of bounds and the bounds themselves. Updates to the bounds are recorded, but the structure of the tree is not. This is particularly useful for depth-first algorithms. As minimal information is stored, yet most GameTreeNode functionality is supported as usual. Note that savedChildren() will always return Optional.empty() and GameTreeNode.children(MetricKeeper...) will always perform a node expansion.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	DepthFirstNode.RootDFNode<P extends IGamePosition<P>>	An optional variant of the DepthFirstNode which stores the nodes at depth 1 in memory.

Nested classes/interfaces inherited from class gametree.GameTreeNode

GameTreeNode.Result<N extends GameTreeNode<N,P>, P extends IGamePosition<P>>

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DepthFirstNode(DepthFirstNode<P> parent, P position, MetricKeeper... metrics)

Method Summary

Modifier and Type	Method	Description
protected boolean	_adjustBounds(List<DepthFirstNode<P>> children, MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.adjustBounds(List<N>, MetricKeeper...).
protected List<DepthFirstNode<P>>	_children(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.children(MetricKeeper...).
protected long	_depthOfLower(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.depthOfLower(MetricKeeper...).
protected long	_depthOfUpper(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.depthOfUpper(MetricKeeper...).
protected double	_lowerbound(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.lowerbound(MetricKeeper...).
protected double	_upperbound(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.upperbound(MetricKeeper...).
static <P extends IGamePosition<P>> DepthFirstNode<P>	getTree(P root, boolean saveRootChildren, MetricKeeper... metrics)	Get a new depth-first game tree based on the provided game position and the saveRootChildren parameter.
boolean	hasSavedBounds()
boolean	maximising()	This is IGamePosition.maximising() from the GameTreeNode.position() of this node.
boolean	readFromTT(Table TT)	Update the bounds of this node with information from a provided transposition table
Optional<List<DepthFirstNode<P>>>	savedChildren()	Always returns an Optional.empty() object, because this class never saves children nodes.
String	toString()

Methods inherited from class gametree.GameTreeNode

adjustBounds, adjustBounds, adjustBounds, adjustBounds, attachMetrics, CDF, children, clearPosition, combineMetricList, countSavedSubTree, depth, depthOfLower, depthOfUpper, findBest2, fromFile, getAllLeafnodes, getAttachedMetrics, getComparator, getSavedLeafnodes, hasAttachedMetrics, isRelevant, isRoot, leastPessimistic2, lowerbound, mostOptimistic2, parent, PMF, position, printTree, printTree, printTree, remainingSolveEffort, separation, separation, setParent, survivalFunction, toFile, updateMetrics, updateMetricsParental, updateTree, upperbound

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

DepthFirstNode

protected DepthFirstNode(DepthFirstNode<P> parent,
 P position,
 MetricKeeper... metrics)

Method Details

getTree

public static <P extends IGamePosition<P>>
DepthFirstNode<P> getTree(P root,
 boolean saveRootChildren,
 MetricKeeper... metrics)

Get a new depth-first game tree based on the provided game position and the saveRootChildren parameter. The provided MetricKeeper objects are attached to the root of the tree and propagated to all children to record the total metrics of the search algorithm(s) utilising this tree.

Type Parameters:

P - The type of game position to store in this game tree

Parameters:

root - The root position of the game tree, this is the current position of the game that all future positions descend from.

saveRootChildren -

metrics -

Returns:

maximising

public boolean maximising()

Description copied from class: GameTreeNode

This is IGamePosition.maximising() from the GameTreeNode.position() of this node.

Specified by:

maximising in class GameTreeNode<DepthFirstNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

Returns:

true if the current player-to-move is maximising the score, or false if it is minimising the score.

_children

protected List<DepthFirstNode<P>> _children(MetricKeeper... metrics)

Description copied from class: GameTreeNode

Method to implement functionality of GameTreeNode.children(MetricKeeper...).

Specified by:

_children in class GameTreeNode<DepthFirstNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

savedChildren

public Optional<List<DepthFirstNode<P>>> savedChildren()

Always returns an Optional.empty() object, because this class never saves children nodes.

Specified by:

savedChildren in class GameTreeNode<DepthFirstNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

Returns:

An Optional containing all children nodes saved in the memory of this GameTreeNode or an empty Optional if none are saved in memory. An Optional containing an empty List signifies a terminal node with no children.

_upperbound

protected double _upperbound(MetricKeeper... metrics)

Description copied from class: GameTreeNode

Method to implement functionality of GameTreeNode.upperbound(MetricKeeper...).

Specified by:

_upperbound in class GameTreeNode<DepthFirstNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

_lowerbound

protected double _lowerbound(MetricKeeper... metrics)

Description copied from class: GameTreeNode

Method to implement functionality of GameTreeNode.lowerbound(MetricKeeper...).

Specified by:

_lowerbound in class GameTreeNode<DepthFirstNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

readFromTT

public boolean readFromTT(Table TT)

Update the bounds of this node with information from a provided transposition table

Parameters:

TT - The transposition table

Returns:

true if this node's bounds were updated, false otherwise.

hasSavedBounds

public boolean hasSavedBounds()

Specified by:

hasSavedBounds in class GameTreeNode<DepthFirstNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

_adjustBounds

protected boolean _adjustBounds(List<DepthFirstNode<P>> children,
 MetricKeeper... metrics)

Description copied from class: GameTreeNode

Method to implement functionality of GameTreeNode.adjustBounds(List<N>, MetricKeeper...).

Specified by:

_adjustBounds in class GameTreeNode<DepthFirstNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

_depthOfUpper

protected long _depthOfUpper(MetricKeeper... metrics)

Description copied from class: GameTreeNode

Method to implement functionality of GameTreeNode.depthOfUpper(MetricKeeper...).

Specified by:

_depthOfUpper in class GameTreeNode<DepthFirstNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

_depthOfLower

protected long _depthOfLower(MetricKeeper... metrics)

Description copied from class: GameTreeNode

Method to implement functionality of GameTreeNode.depthOfLower(MetricKeeper...).

Specified by:

_depthOfLower in class GameTreeNode<DepthFirstNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

toString

public String toString()

Overrides:

toString in class Object