SenoneHMMState.java

/*
* Copyright 1999-2002 Carnegie Mellon University.
* Portions Copyright 2002 Sun Microsystems, Inc.
* Portions Copyright 2002 Mitsubishi Electric Research Laboratories.
* All Rights Reserved.  Use is subject to license terms.
*
* See the file "license.terms" for information on usage and
* redistribution of this file, and for a DISCLAIMER OF ALL
* WARRANTIES.
*
*/

package edu.cmu.sphinx.linguist.acoustic.tiedstate;

import edu.cmu.sphinx.frontend.Data;
import edu.cmu.sphinx.linguist.acoustic.HMM;
import edu.cmu.sphinx.linguist.acoustic.HMMState;
import edu.cmu.sphinx.linguist.acoustic.HMMStateArc;
import edu.cmu.sphinx.util.LogMath;
import edu.cmu.sphinx.util.Utilities;

import java.util.ArrayList;
import java.util.List;

/** Represents a single state in an HMM */
public class SenoneHMMState implements HMMState {

    private final SenoneHMM hmm;
    private final int state;
    HMMStateArc[] arcs;
    private final boolean isEmitting;
    private Senone senone;
    private final int hashCode;

    private static int objectCount;


    /**
     * Constructs a SenoneHMMState
     *
     * @param hmm   the HMM for this state
     * @param which the index for this particular state
     */
    SenoneHMMState(SenoneHMM hmm, int which) {
        this.hmm = hmm;
        this.state = which;
        this.isEmitting = ((hmm.getTransitionMatrix().length - 1) != state);
        if (isEmitting) {
            SenoneSequence ss = hmm.getSenoneSequence();
            senone = ss.getSenones()[state];
        }
        Utilities.objectTracker("HMMState", objectCount++);
        hashCode = hmm.hashCode() + 37 * state;
    }


    /**
     * Gets the HMM associated with this state
     *
     * @return the HMM
     */
    public HMM getHMM() {
    	return hmm;
    }


    /**
     * Gets the state
     *
     * @return the state
     */
    public int getState() {
        return state;
    }


    /**
     * Gets the score for this HMM state
     *
     * @param feature the feature to be scored
     * @return the acoustic score for this state.
     */
    public float getScore(Data feature) {
        return senone.getScore(feature);
    }


    /**
     * Gets the scores for each mixture component in this HMM state
     *
     * @param feature the feature to be scored
     * @return the acoustic scores for the components of this state.
     */
    public float[] calculateComponentScore(Data feature) {
        hmm.getSenoneSequence();
        return senone.calculateComponentScore(feature);
    }


    /**
     * Gets the senone for this HMM state
     *
     * @return the senone for this state.
     */
    public Senone getSenone() {
        return senone;
    }


    /**
     * Determines if two HMMStates are equal
     *
     * @param other the state to compare this one to
     * @return true if the states are equal
     */
    @Override
    public boolean equals(Object other) {
        if (this == other) {
            return true;
        } else if (!(other instanceof SenoneHMMState)) {
            return false;
        } else {
            SenoneHMMState otherState = (SenoneHMMState) other;
            return this.hmm == otherState.hmm &&
                    this.state == otherState.state;
        }
    }


    /**
     * Returns the hashcode for this state
     *
     * @return the hashcode
     */
    @Override
    public int hashCode() {
        return hashCode;
    }


    /**
     * Determines if this HMMState is an emitting state
     *
     * @return true if the state is an emitting state
     */
    // TODO: We may have non-emitting entry states as well.
    public final boolean isEmitting() {
        return isEmitting;
    }


    /**
     * Retrieves the state of successor states for this state
     *
     * @return the set of successor state arcs
     */
    public HMMStateArc[] getSuccessors() {
        if (arcs == null) {
            List<HMMStateArc> list = new ArrayList<HMMStateArc>();
            float[][] transitionMatrix = hmm.getTransitionMatrix();

            for (int i = 0; i < transitionMatrix.length; i++) {
                if (transitionMatrix[state][i] > LogMath.LOG_ZERO) {
                    HMMStateArc arc = new HMMStateArc(hmm.getState(i),
                            transitionMatrix[state][i]);
                    list.add(arc);
                }
            }
            arcs = list.toArray(new HMMStateArc[list.size()]);
        }
        return arcs;
    }


    /**
     * Determines if this state is an exit state of the HMM
     *
     * @return true if the state is an exit state
     */
    public boolean isExitState() {
        // return (hmm.getTransitionMatrix().length - 1) == state;
        return !isEmitting;
    }


    /**
     * returns a string representation of this object
     *
     * @return a string representation
     */
    @Override
    public String toString() {
        return "HMMS " + hmm + " state " + state;
    }

	public MixtureComponent[] getMixtureComponents() {
		return senone.getMixtureComponents();
	}

	public long getMixtureId() {
		return senone.getID();
	}

	public float[] getLogMixtureWeights() {
		return senone.getLogMixtureWeights();
	}
}