Java mean mean(final double[] a)

Description

Calculate the mean of the vector, NaN if it's empty

License

Apache License

Parameter

Parameter	Description
a	a parameter

Return

the mean of the vector

Declaration

final public static double mean(final double[] a) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 *    Copyright 2015, 2016 Taylor G Smith
 *
 *    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./*from w  w  w.  j  a v  a 2 s.  c  o m*/
 *******************************************************************************/

public class Main {
    /**
     * Calculate the mean of the vector, NaN if it's empty
     * @param a
     * @return the mean of the vector
     */
    final public static double mean(final double[] a) {
        return mean(a, sum(a));
    }

    /**
     * Calculate the mean of the vector, given its sum
     * @param a
     * @param sum
     * @return the mean of the vector
     */
    final protected static double mean(final double[] a, final double sum) {
        return sum / a.length;
    }

    public static double sum(final double[] a) {
        double sum = 0.0;
        for (double d : a)
            sum += d;
        return sum;
    }

    /**
     * Returns the count of <tt>true</tt> in a boolean vector
     * @param a
     * @return
     */
    public static int sum(final boolean[] a) {
        int sum = 0;
        for (boolean b : a)
            if (b)
                sum++;
        return sum;
    }
}

Related

1. mean(double[] x, boolean[] used)
2. mean(double[][] image)
3. mean(double[][] input, int column)
4. mean(double[][] matrix)
5. mean(double[][] o)
6. mean(final double[] data, final boolean noNaN)
7. mean(final double[] expected, final int begin, final int end)
8. mean(final double[] in, final int start, final int stop)
9. mean(final double[] values)