edu.stanford.nlp.ie.pcfg
Class XRule

java.lang.Object
  |
  +--edu.stanford.nlp.ie.pcfg.XRule

public class XRule

extends Object

Grammar rules with probabilities.

Field Summary

XLabel	lhs the left-hand side of the rule
double	p the XRule's probability
ArrayList	rhs the right-hand side of the rule.

Constructor Summary

XRule(String s)
creates a new XRule by parsing a string.

XRule(XLabel lhs)
creates a new XRule with an empty RHS and p == 1

Method Summary

void	Copy(XRule fromRule, boolean includeHead, boolean includeTags) copies head and tag information from fromRule.
static List	GetSimilar(XRule rule, List rules, boolean includeHead, boolean includeTags) Gets all the rules in a list that are similar to a key rule.
List	GetTags() gets a list of all tags found anywhere in the rule
static List	GetTags(List rules) gets a list of all tags found anywhere in a list of XRules
int	hashCode() compares this XRule to another object.
static ArrayList	ReadRules(String fn) Reads XRules from a file
boolean	Similar(XRule rule2, boolean includeHead, boolean includeTags) compares two rules.
static boolean	Similar(XRule rule1, XRule rule2, boolean includeHead, boolean includeTags) compares two rules.
String	toString() produces full string representation of XRule.
String	toString(boolean isLex) XRules have the following string format: "LHS -> RHS %% p".
String	toString(boolean includeHead, boolean includeTags) XRules have the following string format: "LHS -> RHS %% p".
String	toString(boolean includeHead, boolean includeLHSTags, boolean includeRHSTags) XRules have the following string format: "LHS -> RHS %% p".
static void	WriteRules(List rules, String fn, boolean isLex) Writes rules to a file.
static void	WriteRules(List rules, String fn, boolean includeHead, boolean includeLHSTags, boolean includeRHSTags) Writes rules to a file.

Methods inherited from class java.lang.Object

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

Field Detail

lhs

public XLabel lhs

the left-hand side of the rule

rhs

public ArrayList rhs

the right-hand side of the rule. a list of XLabels

p

public double p

the XRule's probability

Constructor Detail

XRule

public XRule(XLabel lhs)

creates a new XRule with an empty RHS and p == 1

XRule

public XRule(String s)

creates a new XRule by parsing a string. see toString for format information

Method Detail

toString

public String toString(boolean includeHead,
                       boolean includeLHSTags,
                       boolean includeRHSTags)

XRules have the following string format: "LHS -> RHS %% p". e.g., "S[{purchaser}] -> NP[{purchaser}] VP+bought %% 0.38".

Parameters:

includeHead - true if head information should be included in the output string.

includeLHSTags - true if tag information should be included in the LHS of the output string

toString

public String toString(boolean includeHead,
                       boolean includeTags)

XRules have the following string format: "LHS -> RHS %% p". e.g., "S[{purchaser}] -> NP[{purchaser}] VP+bought %% 0.38".

Parameters:

includeHead - true if head information should be included in the output string.

includeTags - true if tag information should be included in the output string.

toString

public String toString(boolean isLex)

XRules have the following string format: "LHS -> RHS %% p". e.g., "S[{purchaser}] -> NP[{purchaser}] VP+bought %% 0.38".

Parameters:

isLex - calls toString(true, true, !isLex)

toString

public String toString()

produces full string representation of XRule. calls toString(false)

Overrides:

toString in class Object

hashCode

public int hashCode()

compares this XRule to another object.

Overrides:

hashCode in class Object

Returns:

true iff the o is an XRule and it is exactly equal to this XRule. / public boolean equals (Object o) { if (!(o instanceof XRule)) return false; return (toString().equals(o.toString())); } /** returns a hash code for this XRule. Useful when storing XRules in a HashMap

Copy

public void Copy(XRule fromRule,
                 boolean includeHead,
                 boolean includeTags)

copies head and tag information from fromRule. DOES NOT copy type information. Expects that this rule and fromRule have the same RHS length.

Parameters:

fromRule - the rule supplying the head, tag information

includeHead - copy head information

includeTags - copy tag information

Similar

public boolean Similar(XRule rule2,
                       boolean includeHead,
                       boolean includeTags)

compares two rules. ignores (i.e., doesn't consider) XRule probability.

Parameters:

includeHead - if false, ignore head information when making comparison.

includeTags - if false, ignore tag information when making comparison.

Returns:

true if rules are exactly the same (except for ignored information).

Similar

public static boolean Similar(XRule rule1,
                              XRule rule2,
                              boolean includeHead,
                              boolean includeTags)

compares two rules. ignores (i.e., doesn't consider) XRule probability.

Parameters:

includeHead - if false, ignore head information when making comparison

includeTags - if false, ignore tag information when making comparison

GetTags

public List GetTags()

gets a list of all tags found anywhere in the rule

GetTags

public static List GetTags(List rules)

gets a list of all tags found anywhere in a list of XRules

Parameters:

rules - a list of XRules

ReadRules

public static ArrayList ReadRules(String fn)
                           throws IOException

Reads XRules from a file

IOException

WriteRules

public static void WriteRules(List rules,
                              String fn,
                              boolean includeHead,
                              boolean includeLHSTags,
                              boolean includeRHSTags)
                       throws IOException

Writes rules to a file.

Parameters:

rules - a list of XRules

fn - filename

includeHead - write head information

includeLHSTags - write left-hand side tags

includeRHSTags - write right-hand side tags

IOException

WriteRules

public static void WriteRules(List rules,
                              String fn,
                              boolean isLex)
                       throws IOException

Writes rules to a file. Calls WriteRules(rules, fn, true, true, !isLex)

Parameters:

rules - a list of XRules

fn - filename

isLex - if writing a lexicon (as opposed to a grammar). See README

IOException

GetSimilar

public static List GetSimilar(XRule rule,
                              List rules,
                              boolean includeHead,
                              boolean includeTags)

Gets all the rules in a list that are similar to a key rule.

Parameters:

rule - the key

rules - a list of XRules.

includeHead - use head information when computing similarity. see XRule.Similar

includeTags - use tag information when computing similarity. see XRule.Similar

Returns:

every element of rules that is "similar" to rule.