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From: taylor@kronos.arc.nasa.gov (Will Taylor)
Subject: Version 2.6 of AutoClass C Bayesian Classifier
Message-ID: <1995Aug1.162721.24777@ptolemy-ethernet.arc.nasa.gov>
Followup-To: taylor@ptolemy.arc.nasa.gov (Will Taylor)
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Organization: NASA/ARC Computational Sciences Division
Date: Tue, 1 Aug 1995 16:27:21 GMT
Lines: 69


Announcing the release of version 2.6 of AutoClass C, the Bayesian
classifier which seeks a maximum posterior probability classification.

Key features:
 - determines the number of classes automatically;
 - can use mixed discrete and real valued data;
 - can handle missing values;
 - processing time is roughly linear in the amount of the data;
 - cases have probabilistic class membership;
 - allows correlation between attributes within a class;
 - generates reports describing the classes found; and 
 - predicts "test" case class memberships from a "training"
   classification.

Inputs consist of a database of attribute vectors (cases), either real
or discrete valued, and a class model.  Default class models are provided.
AutoClass finds the set of classes that is maximally probable with
respect to the data and model.  The output is a set of class descriptions,
and partial membership of the cases in the classes.

Summary of updates since the initial release on 19 April 1995:

   Version: 1.5	   08 May 95    ported to Sun Solaris 2.4; corrected string
                                overwrite problems; compilation of file
        search-control.c is now optimized; & added binary data file input 
        option.

   Version: 2.0	   08 Jun 95    ported to SGI IRIX version 5.2; converted
                                binary i/o from non-standard (open/close/
        read/write) to ANSI (fopen/fclose/fread/fwrite); converted from 
        srand/rand to srand48/lrand48 for random number generation; added
        prediction capability which uses a "training" classification to
        predict probabilistic class membership for the cases of a "test"
        data file; added new ".s-params" parameter "screen_output_p"; added
        output of real and discrete attribute statistics when data base is
        initially read; corrected garbage output when ".r-params" parameter
        "xref_class_report_att_list" contains mixed real and discrete
        attributes; corrected the handling of unknown real values in reports
        output; and corrected an error in function "output_warning_msgs"
        which caused an abort condition.

   Version: 2.5	   28 Jul 95    Influence values report has been
                                significantly revised and reformatted; 
        add SunOS/Solaris C compiler support; correct segmentation fault
        which occurs when more than 25 type = real, subtype = scalar
        attributes are defined; correct "LOG domain" errors in generation
        of influence values for model "single_multinomial"; and added mods 
        for port to Linux operating system using gcc compiler.

   Version: 2.6	   02 Aug 95    Correct segmentation fault which occurs
                                when more than 50 type = real, subtype = 
        scalar attributes are defined; add function safe_log to prevent 
        "log: SING error" error messages; and require user to confirm 
        search runs using test settings for .s-params file parameters: 
        start_fn_type and randomize_random_p. 

For information on how to get this public domain software, see the following
WWW page,
   http://ic-www.arc.nasa.gov:
     /ic/projects/bayes-group/group/html/autoclass-c-program.html

or send e-mail to taylor@ptolemy.arc.nasa.gov

<<<------------------------------------------------------------------->>>
-- 
Will Taylor > RECOM Technologies, Computational Sciences Div., Code IC
NASA Ames Research Center - voice:(415)604-3364, fax:(415)604-3594
MS 269-2, Moffett Field, CA 94035-1000  taylor@ptolemy.arc.nasa.gov
