Relation Extraction using Link grammars
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This directory is the distribution of version 4.1b of the link grammar
parsing system for UNIX.  This version was created in January, 2005.
It is essentially the same as version 4.1, but is now being released
under a new GPL compatible license, making it freely available for
research and commercial use, with few restrictions.  The terms of the
license are given in the LICENSE file included with this software, and
also available at

Please see our web page for more
information, including documentation.

CONTENTS of this directory:

   LICENSE            The license describing terms of use

   src/*.c            The program.  (Written in ANSI-C)
   obj/*.o            Object files

   data/4.0.dict      The file containing the dictionary definitions.

   data/4.0.knowledge The post-processing knowledge file.

   data/4.0.constituents    The constituent knowledge file.

   data/4.0.affix     The affix file.

   data/tiny.dict     A small sample dictionary.

   data/words/*       A directory full of word lists.

   data/4.0.batch     This is a batch file of sentences (both grammatical
                      and ungrammatical ones) that are handled correctly
                      by this release of the system.  Feed this into the
                      parser with "./parse 4.0.dict < 4.0.batch"

   Makefile           The makefile for creating the program "parse".

CREATING the system:

   To compile the demonstration program included here, simply go to the
   directory containing these files and type:


   This creates a binary file called "parse".  If there are errors, you
   may need to customize the Makefile for your own systems.  Read the
   comments in the Makefile.  This program has been compiled under

RUNNING the program:

   To run the program issue the unix command:


   This starts the program.  Help is available there with "!help".  A
   number of user-settable variables control what happens.  "!var" shows
   these variables and their current values.

   We've used a special batch mode for testing the system on a large
   number of sentences.  The following command runs the parser on

       ./parse 4.0.dict < 4.0.batch

   The line "!batch" near the top of 4.0.batch turns on batch mode.  In
   this mode sentences labeled with an initial "*" should be rejected
   and those not starting with a "*" should be accepted.  Any deviation
   from this behavior is reported as an error.

USING the parser in your own applications:

   There is a API (application program interface) to the parser.  This
   makes it easy to incorporate it into your own applications.  This is
   documented on our web site.


   We feel that our system (or a derivative of it) could be useful in a
   number of commercial applications.  This is allowed under an Apache-style 
   license for release 4.1a. We would be pleased to discuss terms with
   those wanting to use our system under a paid contract.

   Of course all academic products or papers should reference our work.


   If you have any questions, or find any bugs, please feel free to send
   a note to:

     Daniel Sleator            
     Computer Science Department       412-268-7563
     Carnegie Mellon University
     Pittsburgh, PA 15213              

     Davy Temperley          
     Eastman School of Music	       716-274-1557
     26 Gibbs St.	     
     Rochester, NY 14604

     John Lafferty           
     Computer Science Department       412-268-6791
     Carnegie Mellon University
     Pittsburgh, PA 15213