org.moyoman.module.lifeanddeath
Interface LifeAndDeath

All Superinterfaces:

Cloneable, ModuleInterface, Serializable

public interface LifeAndDeath

extends ModuleInterface

Any class which implements this interface will be performing a life and death analysis for each loose group on the board. Unlike life and death problems in books, a life and death module for a Go playing program must deal with a much broader class of problems. Some of the issues which must be addressed are:

• Some groups may not be surrounded, and so a life and death analysis cannot be done.
• For whatever reason, the module may not be able to determine the status of a particular group.
• For groups where an exact result cannot be computed, a probability of life needs to be determined.
• Groups which are alive or dead are still a source of ko threats to live or die.
• Rather than making eyes, the solution may be to break out of containment.
• Book problems tend to be for cases that are on the edge of life. The module needs to deal efficiently with groups that are clearly alive or clearly dead.

This is a low level module. In determining the status of a group, the consequences of this play on other groups is not considered. So, factors such as splitting attacks or weakening nearby groups are not considered. This type of analysis is left to higher level modules.

Field Summary

static short

LARGE_NUMBER This value is returned by methods such as numberOfMoveToKill() if the group can't be killed.

Method Summary

Stone[]	findKoThreatsToBreakContainment(SingleLooseGroup slg) Find all moves that threaten to break out of containment.
Stone[]	findKoThreatsToContain(SingleLooseGroup slg) Find all moves that threaten to contain the group on the next move.
Stone[]	findKoThreatsToKill(SingleLooseGroup slg) Find all moves that threaten to kill the group on the next move.
Stone[]	findKoThreatsToLive(SingleLooseGroup slg) Find all moves that threaten to make the group live on the next move.
MoveDescriptorForest	getSequences(SingleLooseGroup slg) Get possible sequences of play For attack, the sequence could threaten to contain or kill, while for defense, the sequence could threaten to break out or make life.
LDStatus	getStatusIfContained(SingleLooseGroup slg) Determine the status of the group if additional enemy stones were present to contain it.
short	numberOfMovesToContain(SingleLooseGroup slg) Get the number of moves to contain the group.
short	numberOfMovesToKill(SingleLooseGroup slg) Get the number of moves to kill the group.
short	numberOfMovesToLive(SingleLooseGroup slg) Get the number of moves to live.
float	safety(SingleLooseGroup slg) Rate the safety of the group.
LDStatus	status(SingleLooseGroup slg) Return an LDStatus object which describes the life and death status of the group in question.

Methods inherited from interface org.moyoman.module.ModuleInterface

clone, getMoves, getScheduler

Field Detail

LARGE_NUMBER

public static final short LARGE_NUMBER

This value is returned by methods such as numberOfMoveToKill() if the group can't be killed.

See Also:

Constant Field Values

Method Detail

status

public LDStatus status(SingleLooseGroup slg)

Return an LDStatus object which describes the life and death status of the group in question.

Returns:

An LDStatus object.

getSequences

public MoveDescriptorForest getSequences(SingleLooseGroup slg)

Get possible sequences of play For attack, the sequence could threaten to contain or kill, while for defense, the sequence could threaten to break out or make life.

Parameters:

slg - The loose group in question.

Returns:

A MoveDescriptorForest object describing sequences of play.

numberOfMovesToKill

public short numberOfMovesToKill(SingleLooseGroup slg)

Get the number of moves to kill the group.

Parameters:

slg - The loose group in question.

Returns:

A short which is the number of moves to kill, or LARGE_NUMBER if the group can't be killed.

numberOfMovesToLive

public short numberOfMovesToLive(SingleLooseGroup slg)

Get the number of moves to live.

Parameters:

slg - The loose group in question.

Returns:

A short which is the number of moves to live, or LARGE_NUMBER if the group cannot be made to live.

numberOfMovesToContain

public short numberOfMovesToContain(SingleLooseGroup slg)

Get the number of moves to contain the group.

Returns:

A short which is the number of moves to contain the group.

findKoThreatsToKill

public Stone[] findKoThreatsToKill(SingleLooseGroup slg)

Find all moves that threaten to kill the group on the next move.

Parameters:

slg - The loose group in question.

Returns:

An array of Stone objects.

findKoThreatsToLive

public Stone[] findKoThreatsToLive(SingleLooseGroup slg)

Find all moves that threaten to make the group live on the next move.

Parameters:

slg - The loose group in question.

Returns:

An array of Stone objects.

findKoThreatsToContain

public Stone[] findKoThreatsToContain(SingleLooseGroup slg)

Find all moves that threaten to contain the group on the next move. It is not implied that containing the group automatically kills it.

Parameters:

slg - The loose group in question.

Returns:

An array of Stone objects.

findKoThreatsToBreakContainment

public Stone[] findKoThreatsToBreakContainment(SingleLooseGroup slg)

Find all moves that threaten to break out of containment.

Parameters:

slg - The loose group in question.

Returns:

An array of Stone objects.

getStatusIfContained

public LDStatus getStatusIfContained(SingleLooseGroup slg)

Determine the status of the group if additional enemy stones were present to contain it. If the group is already contained, then this method returns the same value as status().

Parameters:

slg - The loose group in question.

Returns:

An LDStatus object for the contained group.

safety

public float safety(SingleLooseGroup slg)

Rate the safety of the group. This method is most important for uncontained or undetermined groups. It does not take higher level considerations into account to determine who will win a ko.

Parameters:

slg - The loose group in question.

Returns:

A float in the range of 0.0 to 1.0.