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    1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2011-2014, VU University Amsterdam
    7    All rights reserved.
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    9    Redistribution and use in source and binary forms, with or without
   10    modification, are permitted provided that the following conditions
   11    are met:
   12
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   14       notice, this list of conditions and the following disclaimer.
   15
   16    2. Redistributions in binary form must reproduce the above copyright
   17       notice, this list of conditions and the following disclaimer in
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   19       distribution.
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   21    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   22    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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   24    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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   33*/
   34
   35:- module(isub,
   36          [ isub/4                      % +Text1, +Text2, +Normalize, -Distance
   37          ]).   38
   39
   40:- use_foreign_library(foreign(isub)).

isub: a string similarity measure

The library(isub) implements a similarity measure between strings, i.e., something similar to the Levenshtein distance. This method is based on the length of common substrings.

author
- Giorgos Stoilos
See also
- A string metric for ontology alignment by Giorgos Stoilos, 2005. */
 isub(+Text1:text, +Text2:text, +Normalize:bool, -Similarity:float) is det
Similarity is a measure for the distance between Text1 and Text2. E.g.
?- isub('E56.Language', 'languange', true, D).
D = 0.711348.

If Normalize is true, isub/4 applies string normalization as implemented by the original authors: Text1 and Text2 are mapped to lowercase and the characters "._ " are removed. Lowercase mapping is done with the C-library function towlower(). In general, the required normalization is domain dependent and is better left to the caller. See e.g., unaccent_atom/2.

Arguments:
Text1- and Text2 are either an atom, string or a list of characters or character codes.
Similarity- is a float in the range [0.0..1.0], where 1.0 means most similar
   76:- multifile sandbox:safe_primitive/1.   77
   78sandbox:safe_primitive(isub:isub(_,_,_,_))