Computes the cumulative sum of the specified array in place. - Java java.lang

Java examples for java.lang:Math Array Function

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Description

Computes the cumulative sum of the specified array in place.

Demo Code

/**/*w w w.  j  a v a  2  s .c  om*/
 * Java Modular Image Synthesis Toolkit (JMIST)
 * Copyright (C) 2008-2013 Bradley W. Kimmel
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
//package com.java2s;

import java.util.List;

public class Main {
    /**
     * Computes the cumulative sum of the specified array in place.
     *
     * Each element <code>x[i]</code> is replaced with
     * <code>x[0] + ... + x[i]</code>.
     *
     * @param x The array of doubles for which to compute the cumulative sum.
     * @return A reference to <code>x</code>.
     */
    public static double[] cumsum(double[] x) {
        for (int i = 1; i < x.length; i++) {
            x[i] += x[i - 1];
        }
        return x;
    }

    /**
     * Computes the cumulative sum of the specified array in place.
     *
     * Each element <code>x[i]</code> is replaced with
     * <code>x[0] + ... + x[i]</code>.
     *
     * @param x The array of ints for which to compute the cumulative sum.
     * @return A reference to <code>x</code>.
     */
    public static int[] cumsum(int[] x) {
        for (int i = 1; i < x.length; i++) {
            x[i] += x[i - 1];
        }
        return x;
    }

    /**
     * Computes the cumulative sum of the specified array in place.
     *
     * Each element <code>x[i]</code> is replaced with
     * <code>x[0] + ... + x[i]</code>.
     *
     * @param x The array of doubles for which to compute the cumulative sum.
     * @return A reference to <code>x</code>.
     */
    public static long[] cumsum(long[] x) {
        for (int i = 1; i < x.length; i++) {
            x[i] += x[i - 1];
        }
        return x;
    }

    /**
     * Computes the cumulative sum of the specified <code>List</code> in place.
     *
     * Each element <code>x.get(i)</code> is replaced with
     * <code>x.get(0) + ... + x.get(1)</code>.
     *
     * @param x The <code>List</code> of doubles for which to compute the
     *     cumulative sum.
     * @return A reference to <code>x</code>.
     */
    public static List<Double> cumsum(List<Double> x) {
        for (int i = 1, n = x.size(); i < n; i++) {
            x.set(i, x.get(i) + x.get(i - 1));
        }
        return x;
    }
}

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