edu.umass.cs.mallet.base.types
Class StringKernel

java.lang.Object
  java.util.AbstractMap
      java.util.HashMap
          java.util.LinkedHashMap
              edu.umass.cs.mallet.base.types.StringKernel

All Implemented Interfaces:

java.lang.Cloneable, java.util.Map, java.io.Serializable

public class StringKernel

extends java.util.LinkedHashMap

Computes a similarity metric between two strings, based on counts of common subsequences of characters. See Lodhi et al "String kernels for text classification." Optionally caches previous kernel computations.

See Also:

Serialized Form

Constructor Summary

StringKernel()

StringKernel(boolean norm, double lam, int length)

StringKernel(boolean norm, double lam, int length, boolean cache)

Method Summary

double	K(java.lang.String s, java.lang.String t) Computes the normalized string kernel between two strings.
static void	main(java.lang.String[] args) Return string kernel between two strings

Methods inherited from class java.util.LinkedHashMap

clear, containsValue, get, removeEldestEntry

Methods inherited from class java.util.HashMap

clone, containsKey, entrySet, isEmpty, keySet, put, putAll, remove, size, values

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

StringKernel

public StringKernel(boolean norm,
                    double lam,
                    int length,
                    boolean cache)

Parameters:

norm - true if we lowercase all strings

lam - 0-1 penalty for gaps between matches.

length - max length of subsequences to compare

cache - true if we should cache previous kernel computations. recommended!

StringKernel

public StringKernel()

StringKernel

public StringKernel(boolean norm,
                    double lam,
                    int length)

Method Detail

K

public double K(java.lang.String s,
                java.lang.String t)

Computes the normalized string kernel between two strings.

Parameters:

s - string 1

t - string 2

Returns:

0-1 value, where 1 is exact match.

main

public static void main(java.lang.String[] args)
                 throws java.lang.Exception

Return string kernel between two strings

Throws:

java.lang.Exception