maxentmodel.java

最大熵模型源代码

///////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2001 Jason Baldridge and Gann Bierner
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
//////////////////////////////////////////////////////////////////////////////   
package opennlp.maxent;

/**
 * Interface for maximum entropy models.
 *
 * @author      Jason Baldridge
 * @version     $Revision: 1.3 $, $Date: 2001/11/30 14:33:29 $
 **/
public interface MaxentModel {

    /**
     * Evaluates a context.
     *
     * @param context A list of String names of the contextual predicates
     *                which are to be evaluated together.
     * @return an array of the probabilities for each of the different
     *         outcomes, all of which sum to 1.
     *
     **/
    public double[] eval (String[] context);

    /**
     * Simple function to return the outcome associated with the index
     * containing the highest probability in the double[].
     *
     * @param outcomes A <code>double[]</code> as returned by the
     *            <code>eval(String[] context)</code>
     *            method.
     * @return the String name of the best outcome
     **/
    public String getBestOutcome (double[] outcomes);


    /**
     * Return a string matching all the outcome names with all the
     * probabilities produced by the <code>eval(String[]
     * context)</code> method.
     *
     * @param outcomes A <code>double[]</code> as returned by the
     *            <code>eval(String[] context)</code>
     *            method.
     * @return    String containing outcome names paired with the normalized
     *            probability (contained in the <code>double[] ocs</code>)
     *            for each one.
     **/    
    public String getAllOutcomes (double[] outcomes);

	
    /**
     * Gets the String name of the outcome associated with the index
     * i.
     *
     * @param i the index for which the name of the associated outcome is
     *          desired.
     * @return the String name of the outcome
     **/
    public String getOutcome (int i);


    /**
     * Gets the index associated with the String name of the given
     * outcome.
     *
     * @param outcome the String name of the outcome for which the
     *          index is desired
     * @return the index if the given outcome label exists for this
     * model, -1 if it does not.
     **/
    public int getIndex (String outcome);


    /**
     * Returns the data structures relevant to storing the model.
     **/
    public Object[] getDataStructures ();
    
}