aima.core.nlp.parsing.grammars

Class ProbUnrestrictedGrammar

java.lang.Object

aima.core.nlp.parsing.grammars.ProbUnrestrictedGrammar

All Implemented Interfaces:

ProbabilisticGrammar

Direct Known Subclasses:

ProbContextSensitiveGrammar

public class ProbUnrestrictedGrammar
extends java.lang.Object
implements ProbabilisticGrammar

Represents the most general grammatical formalism, the Unrestricted (or Recrusively Enumerable) Grammar. All other grammars can derive from this grammar, imposing extra restrictions.

Author:

Jonathon

Field Summary

Fields

Modifier and Type	Field and Description
static int	CNFGRAMMAR
static int	CONTEXT_FREE
static int	CONTEXT_SENSITIVE
static int	PROB_CONTEXT_FREE
static int	REGULAR
java.util.List<Rule>	rules
java.util.List<java.lang.String>	terminals
int	type
static int	UNRESTRICTED
java.util.List<java.lang.String>	vars

Constructor Summary

Constructors

Constructor and Description
ProbUnrestrictedGrammar()

Method Summary

Modifier and Type	Method and Description
boolean	addRule(Rule rule) Add a single rule the grammar, testing it for structural and probability validity.
boolean	addRules(java.util.List<Rule> ruleList) Add a number of rules at once, testing each in turn for validity, and then testing the batch for probability validity.
static boolean	isTerminal(java.lang.String s) Check if we have a terminal, as they are lowercase strings
static boolean	isVariable(java.lang.String s) Check if we have a variable, as they are uppercase strings.
java.lang.String	toString()
void	updateVarsAndTerminals() Whenever a new rule is added to the grammar, we want to update the list of variables and terminals with any new grammar symbols
void	updateVarsAndTerminals(Rule r) Update variable and terminal lists with a single rule's symbols, if there a new symbols
boolean	validateRuleProbabilities(java.util.List<Rule> ruleList) For a set of rules, test whether each batch of rules with the same LHS have their probabilities sum to exactly 1.0
boolean	validRule(Rule r) Test validity of the LHS and RHS of grammar rule.

Methods inherited from class java.lang.Object

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

Field Detail

UNRESTRICTED

public static final int UNRESTRICTED

See Also:

Constant Field Values

CONTEXT_SENSITIVE

public static final int CONTEXT_SENSITIVE

See Also:

Constant Field Values

CONTEXT_FREE

public static final int CONTEXT_FREE

See Also:

Constant Field Values

REGULAR

public static final int REGULAR

See Also:

Constant Field Values

CNFGRAMMAR

public static final int CNFGRAMMAR

See Also:

Constant Field Values

PROB_CONTEXT_FREE

public static final int PROB_CONTEXT_FREE

See Also:

Constant Field Values

rules

public java.util.List<Rule> rules

vars

public java.util.List<java.lang.String> vars

terminals

public java.util.List<java.lang.String> terminals

type

public int type

Constructor Detail

ProbUnrestrictedGrammar

public ProbUnrestrictedGrammar()

Method Detail

addRules

public boolean addRules(java.util.List<Rule> ruleList)

Add a number of rules at once, testing each in turn for validity, and then testing the batch for probability validity.

Specified by:

addRules in interface ProbabilisticGrammar

Parameters:

ruleList -

Returns:

true if rules are valid and incorporated into the grammar. false, otherwise

addRule

public boolean addRule(Rule rule)

Add a single rule the grammar, testing it for structural and probability validity.

Specified by:

addRule in interface ProbabilisticGrammar

Parameters:

rule -

Returns:

true if rule is incorporated. false, otherwise

validateRuleProbabilities

public boolean validateRuleProbabilities(java.util.List<Rule> ruleList)

For a set of rules, test whether each batch of rules with the same LHS have their probabilities sum to exactly 1.0

Specified by:

validateRuleProbabilities in interface ProbabilisticGrammar

Parameters:

ruleList -

Returns:

true if the probabilities are valid. false, otherwise

validRule

public boolean validRule(Rule r)

Test validity of the LHS and RHS of grammar rule. In unrestricted grammar, the only invalid rule type is a rule with a null LHS.

Specified by:

validRule in interface ProbabilisticGrammar

Parameters:

r - ( a rule )

Returns:

true, if rule has valid form. false, otherwise

updateVarsAndTerminals

public void updateVarsAndTerminals()

Whenever a new rule is added to the grammar, we want to update the list of variables and terminals with any new grammar symbols

Specified by:

updateVarsAndTerminals in interface ProbabilisticGrammar

updateVarsAndTerminals

public void updateVarsAndTerminals(Rule r)

Update variable and terminal lists with a single rule's symbols, if there a new symbols

Specified by:

updateVarsAndTerminals in interface ProbabilisticGrammar

Parameters:

r -

isVariable

public static boolean isVariable(java.lang.String s)

Check if we have a variable, as they are uppercase strings.

Parameters:

s -

Returns:

isTerminal

public static boolean isTerminal(java.lang.String s)

Check if we have a terminal, as they are lowercase strings

Parameters:

s -

Returns:

true, if string must be a terminal. false, otherwise

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object