Class SearchTreeNode<P extends IGamePosition<P>>

java.lang.Object

gametree.GameTreeNode<SearchTreeNode<P>, P>

gametree.SearchTreeNode<P>

Type Parameters:

P - some implementation of IGamePosition which corresponds to the game being searched by this tree.

All Implemented Interfaces:

Serializable

public class SearchTreeNode<P extends IGamePosition<P>>
extends GameTreeNode<SearchTreeNode<P>, P>
implements Serializable

Implementation of GameTreeNode that stores all nodes directly in memory. This search tree is editable through search only (by expanding nodes and adjusting their bounds), so the resulting tree always represents the game given by the IGamePosition implementation P correctly.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SearchTreeNode.Settings	A class that stores the settings for a SearchTreeNode tree.

Nested classes/interfaces inherited from class gametree.GameTreeNode

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

Field Summary

Fields

Modifier and Type	Field	Description
protected SearchTreeNode.Settings	settings

Constructor Summary

Constructors

Constructor	Description
SearchTreeNode(SearchTreeNode.Settings settings, SearchTreeNode<P> parent, P position, MetricKeeper... metrics)
SearchTreeNode(SearchTreeNode.Settings settings, P position, MetricKeeper... metrics)

Method Summary

Modifier and Type	Method	Description
boolean	_adjustBounds(List<SearchTreeNode<P>> children, MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.adjustBounds(List<N>, MetricKeeper...).
ArrayList<SearchTreeNode<P>>	_children(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.children(MetricKeeper...).
long	_depthOfLower(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.depthOfLower(MetricKeeper...).
long	_depthOfUpper(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.depthOfUpper(MetricKeeper...).
double	_lowerbound(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.lowerbound(MetricKeeper...).
double	_upperbound(MetricKeeper... metrics)	Method to implement functionality of GameTreeNode.upperbound(MetricKeeper...).
boolean	allowModifications()
void	attachMetrics(MetricKeeper... metrics)
protected SearchTreeNode<P>	createChild(SearchTreeNode<P> parent, P position)
void	disableIrrelevancePruning()	Disables pruning of irrelevant children nodes in the entire tree.
void	disablePositionPruning()	Disables pruning of game positions GameTreeNode.position() values for nodes after they have been expanded and evaluated - which is enabled by calling enablePositionPruning(long) on any node of the tree.
void	enableIncorrectBoundsProtection(boolean set)	If set to true, enables incorrect-bounds protection for the pruning of irrelevant children nodes in the entire tree.
void	enableIrrelevancePruning(long minimum_depth_to_prune)	Enables pruning of irrelevant children nodes in the entire tree.
void	enablePositionPruning(long minimum_depth_to_prune)	Enables pruning of game positions GameTreeNode.position() values for nodes after they have been expanded and evaluated.
boolean	evaluate(MetricKeeper... metrics)	Evaluates this node if the tree has not been frozen in the settings.
void	freeze()	setTreeFrozen(boolean) with frozen = true.
static <P extends IGamePosition<P>> SearchTreeNode<P>	getTree(P start_position)
static <P extends IGamePosition<P>> SearchTreeNode<P>	getTree(P start_position, boolean prune_positions, boolean prune_irrelevance)
static <P extends IGamePosition<P>> SearchTreeNode<P>	getTree(P start_position, boolean prune_positions, long minimum_depth_to_prune_positions, boolean prune_irrelevance, long minimum_depth_to_prune_irrelevance)
static <P extends IGamePosition<P>> SearchTreeNode<P>	getTree(P start_position, boolean prune_positions, long minimum_depth_to_prune_positions, boolean prune_irrelevance, long minimum_depth_to_prune_irrelevance, boolean incorrect_bounds_protection_for_irrelevance_pruning)
static <P extends IGamePosition<P>> SearchTreeNode<P>	getTree(P start_position, long minimum_depth_to_prune_positions, long minimum_depth_to_prune_irrelevance)
boolean	hasSavedBounds()
boolean	isEvaluated()
boolean	isPruned()
boolean	maximising()	This is IGamePosition.maximising() from the GameTreeNode.position() of this node.
boolean	pruneIrrelevantChildren(MetricKeeper[] m)
void	prunePosition()	Prunes the GameTreeNode.position() value of this node if enabled in the settings.
void	removeChildren(boolean markAsPruned)
Optional<List<SearchTreeNode<P>>>	savedChildren()
void	setAllowModifications(boolean set)
boolean	setBounds(double lowerbound, double upperbound)
void	setChildren(Collection<SearchTreeNode<P>> newChildren)
SearchTreeNode.Settings	settings()
void	setTreeFrozen(boolean frozen)	Freezes or un-freezes the SearchTreeNode tree this node is a part of.
String	toString()
void	unfreeze()	setTreeFrozen(boolean) with frozen = false.

Methods inherited from class gametree.GameTreeNode

adjustBounds, adjustBounds, adjustBounds, adjustBounds, 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

Field Details

settings

protected SearchTreeNode.Settings settings

Constructor Details

SearchTreeNode

public SearchTreeNode(SearchTreeNode.Settings settings,
 SearchTreeNode<P> parent,
 P position,
 MetricKeeper... metrics)

SearchTreeNode

public SearchTreeNode(SearchTreeNode.Settings settings,
 P position,
 MetricKeeper... metrics)

Method Details

settings

public SearchTreeNode.Settings settings()

getTree

public static <P extends IGamePosition<P>>
SearchTreeNode<P> getTree(P start_position,
 boolean prune_positions,
 long minimum_depth_to_prune_positions,
 boolean prune_irrelevance,
 long minimum_depth_to_prune_irrelevance,
 boolean incorrect_bounds_protection_for_irrelevance_pruning)

getTree

public static <P extends IGamePosition<P>>
SearchTreeNode<P> getTree(P start_position,
 boolean prune_positions,
 long minimum_depth_to_prune_positions,
 boolean prune_irrelevance,
 long minimum_depth_to_prune_irrelevance)

getTree

public static <P extends IGamePosition<P>>
SearchTreeNode<P> getTree(P start_position,
 long minimum_depth_to_prune_positions,
 long minimum_depth_to_prune_irrelevance)

getTree

public static <P extends IGamePosition<P>>
SearchTreeNode<P> getTree(P start_position,
 boolean prune_positions,
 boolean prune_irrelevance)

getTree

public static <P extends IGamePosition<P>>
SearchTreeNode<P> getTree(P start_position)

setTreeFrozen

public void setTreeFrozen(boolean frozen)

Freezes or un-freezes the SearchTreeNode tree this node is a part of. Frozen trees do not allow any node expansions, evaluations, or modifications to take place. This is useful for displaying the tree without modifying it.

Parameters:

frozen - true to prevent new node expansions or evaluations. Or false to enable new node expansions and evaluations. This setting defaults to true for all new trees.

freeze

public void freeze()

setTreeFrozen(boolean) with frozen = true. Freezes the tree this node is a part of - disabling any modifications until unfreeze() or setTreeFrozen(boolean) are called.

unfreeze

public void unfreeze()

setTreeFrozen(boolean) with frozen = false. Unfreezes the tree this node is a part of - enabling all modifications until freeze() or setTreeFrozen(boolean) are called.

setAllowModifications

public void setAllowModifications(boolean set)

allowModifications

public boolean allowModifications()

enablePositionPruning

public void enablePositionPruning(long minimum_depth_to_prune)

Enables pruning of game positions GameTreeNode.position() values for nodes after they have been expanded and evaluated. This does not retroactively remove game positions, but only enables it from this moment on. A position that has been pruned can not be recovered. This only affects the functionality of GameTreeNode.position(), which will return null when a node is pruned, the tree still functions normally in every other aspect. This reduces the memory usage of future expansions of the tree by not keeping all game positions in memory.

This can be disabled again by calling disablePositionPruning() on any node of the same tree.

Parameters:

minimum_depth_to_prune - minimum depth from the root node (where depth = 0). This refers to the root of the entire tree this node is in.

disablePositionPruning

public void disablePositionPruning()

Disables pruning of game positions GameTreeNode.position() values for nodes after they have been expanded and evaluated - which is enabled by calling enablePositionPruning(long) on any node of the tree. Does not retroactively modify the tree in any way.

enableIrrelevancePruning

public void enableIrrelevancePruning(long minimum_depth_to_prune)

Enables pruning of irrelevant children nodes in the entire tree. No nodes will be retroactively pruned. Can be disabled by calling disableIrrelevancePruning().

Parameters:

minimum_depth_to_prune - the minimum depth at which nodes will be pruned. To preserve node structure at the children of the root, set this value to 2 or higher.

disableIrrelevancePruning

public void disableIrrelevancePruning()

Disables pruning of irrelevant children nodes in the entire tree. Does not retroactively modify the tree in any way. Nodes already pruned can not be restored. Can be re-enabled by calling enableIrrelevancePruning(long).

enableIncorrectBoundsProtection

public void enableIncorrectBoundsProtection(boolean set)

If set to true, enables incorrect-bounds protection for the pruning of irrelevant children nodes in the entire tree. This ensures that nodes pruned by enableIrrelevancePruning(long) are still kept in memory, but only their children are removed. This ensures the node can still be revisited if it becomes relevant again later (due to the evaluation function having incorrect bounds). It is important to note that this may result in a null error if enablePositionPruning(long) is enabled. Can be disabled by calling setting to false. Defaults to false.

This does not retroactively modify the tree in any way.

Parameters:

set - the value to set to

_children

public ArrayList<SearchTreeNode<P>> _children(MetricKeeper... metrics)

Description copied from class: GameTreeNode

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

Specified by:

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

createChild

protected SearchTreeNode<P> createChild(SearchTreeNode<P> parent,
 P position)

savedChildren

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

Specified by:

savedChildren in class GameTreeNode<SearchTreeNode<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.

prunePosition

public void prunePosition()

Prunes the GameTreeNode.position() value of this node if enabled in the settings. Only prunes nodes at a minimum depth of SearchTreeNode.Settings.position_pruning_depth that have already been expanded and evaluated.

evaluate

public boolean evaluate(MetricKeeper... metrics)

Evaluates this node if the tree has not been frozen in the settings. Does nothing if the node has already been evaluated.

Parameters:

metrics - An array of metric keepers to keep track of the evaluations made through this method

Returns:

true if the node has been evaluated. false if the node is not yet evaluated after this method call (only when the tree is frozen and node not yet evaluated).

setBounds

public boolean setBounds(double lowerbound,
 double upperbound)

removeChildren

public void removeChildren(boolean markAsPruned)

setChildren

public void setChildren(Collection<SearchTreeNode<P>> newChildren)

isEvaluated

public boolean isEvaluated()

_upperbound

public double _upperbound(MetricKeeper... metrics)

Description copied from class: GameTreeNode

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

Specified by:

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

_lowerbound

public double _lowerbound(MetricKeeper... metrics)

Description copied from class: GameTreeNode

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

Specified by:

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

hasSavedBounds

public boolean hasSavedBounds()

Specified by:

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

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<SearchTreeNode<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.

_adjustBounds

public boolean _adjustBounds(List<SearchTreeNode<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<SearchTreeNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

pruneIrrelevantChildren

public boolean pruneIrrelevantChildren(MetricKeeper[] m)

isPruned

public boolean isPruned()

_depthOfUpper

public long _depthOfUpper(MetricKeeper... metrics)

Description copied from class: GameTreeNode

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

Specified by:

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

_depthOfLower

public long _depthOfLower(MetricKeeper... metrics)

Description copied from class: GameTreeNode

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

Specified by:

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

attachMetrics

public void attachMetrics(MetricKeeper... metrics)

Overrides:

attachMetrics in class GameTreeNode<SearchTreeNode<P extends IGamePosition<P>>, P extends IGamePosition<P>>

toString

public String toString()

Overrides:

toString in class Object