Gets the gaussian pdf value constant term log. - Java java.lang

Java examples for java.lang:Math Trigonometric Function

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Description

Gets the gaussian pdf value constant term log.

Demo Code

/**// ww w  .j a va 2  s  .c  o  m
 * Copyright 2004-2006 DFKI GmbH.
 * All Rights Reserved.  Use is subject to license terms.
 * 
 * Permission is hereby granted, free of charge, to use and distribute
 * this software and its documentation without restriction, including
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 * permit persons to whom this work is furnished to do so, subject to
 * the following conditions:
 * 
 * 1. The code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 * 2. Any modifications must be clearly marked as such.
 * 3. Original authors' names are not deleted.
 * 4. The authors' names are not used to endorse or promote products
 *    derived from this software without specific prior written
 *    permission.
 *
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 * REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL DFKI GMBH NOR THE
 * CONTRIBUTORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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 */
//package com.java2s;

public class Main {
    /**
     * Gets the gaussian pdf value constant term log.
     *
     * @param featureDimension the feature dimension
     * @param detCovarianceMatrix the det covariance matrix
     * @return the gaussian pdf value constant term log
     */
    public static double getGaussianPdfValueConstantTermLog(
            int featureDimension, double detCovarianceMatrix) {
        double constantTermLog = 0.5 * featureDimension
                * Math.log(2 * Math.PI); //double constantTerm = Math.pow(2*Math.PI, 0.5*featureDimension);
        constantTermLog += Math.log(Math.sqrt(detCovarianceMatrix));
        constantTermLog = -constantTermLog;

        return constantTermLog;
    }

    /**
     * Log.
     *
     * @param a the a
     * @return the double[]
     */
    public static double[] log(double[] a) {
        double[] c = new double[a.length];
        for (int i = 0; i < a.length; i++) {
            c[i] = Math.log(a[i]);
        }
        return c;
    }

    /**
     * Log.
     *
     * @param a the a
     * @param minimumValue the minimum value
     * @param fixedValue the fixed value
     * @return the double[]
     */
    public static double[] log(double[] a, double minimumValue,
            double fixedValue) {
        double[] c = new double[a.length];
        for (int i = 0; i < a.length; i++) {
            if (a[i] > minimumValue)
                c[i] = Math.log(a[i]);
            else
                c[i] = fixedValue;
        }
        return c;
    }
}

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