Model.java

/*
 * Copyright (c) 2011 The S4 Project, http://s4.io.
 * All rights reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *          http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the
 * License. See accompanying LICENSE file. 
 */
package org.apache.s4.model;

/**
 * 
 * Base class for statistical models.
 * 
 * @author Leo Neumeyer
 * 
 */
abstract public class Model {

    protected boolean isTrain;
    protected String name;

    public Model() {
    }

    public Model(String name, boolean isTrain) {
        this.name = name;
        this.isTrain = isTrain;
    }

    /**
     * Return an instance of this model initialized with the same parameters as its parent.
     * 
     * @return a copy of the parent model.
     */
    abstract public Model create();

    /**
     * Compute the probability of the observed vector.
     * 
     * @param obs
     *            An observed data vector.
     * @return the probability.
     */
    abstract public double prob(float[] obs);

    /**
     * Compute the log probability of the observed vector.
     * 
     * @param obs
     *            An observed data vector.
     * @return the log probability.
     */
    abstract public double logProb(float[] obs);

    /**
     * Update sufficient statistics/
     * 
     * @param obs
     *            An observed data vector.
     */
    abstract public void update(float[] obs);

    /** Estimate model parameters. */
    abstract public void estimate();

    /** Clear sufficient statistics. */
    abstract public void clearStatistics();

    /** @return true if training resources have been initialized. */
    public boolean isTrain() {
        return isTrain;
    }

    /**
     * @param train
     *            set train.
     */
    public void setTrain(boolean isTrain) {
        this.isTrain = isTrain;
    }

    /** @return model name. */
    public String getName() {
        return name;
    }

    /** Set model name. */
    public void setName(String name) {
        this.name = name;
    }
}