Computes the dot product of two vectors. - Java java.lang

Java examples for java.lang:Math Vector

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Description

Computes the dot product of two vectors.

Demo Code

/**/*from   w ww  . j av a  2s  .  co m*/
 * 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;

public class Main {
    /**
     * Computes the dot product of two vectors.
     * @param a The first array.
     * @param b The second array.
     * @return The sum of <code>a[i] * b[i]</code>.
     * @throws IllegalArgumentException if <code>a.length != b.length</code>.
     */
    public static double dot(double[] a, double[] b) {
        if (a.length != b.length) {
            throw new IllegalArgumentException("a.length != b.length");
        }
        double sum = 0.0;
        for (int i = 0; i < a.length; i++) {
            sum += a[i] * b[i];
        }
        return sum;
    }

    /**
     * Computes the dot product of two vectors.
     * @param a The first array.
     * @param b The second array.
     * @return The sum of <code>a[i] * b[i]</code>.
     * @throws IllegalArgumentException if <code>a.length != b.length</code>.
     */
    public static int dot(int[] a, int[] b) {
        if (a.length != b.length) {
            throw new IllegalArgumentException("a.length != b.length");
        }
        int sum = 0;
        for (int i = 0; i < a.length; i++) {
            sum += a[i] * b[i];
        }
        return sum;
    }

    /**
     * Computes the dot product of two vectors.
     * @param a The first array.
     * @param b The second array.
     * @return The sum of <code>a[i] * b[i]</code>.
     * @throws IllegalArgumentException if <code>a.length != b.length</code>.
     */
    public static long dot(long[] a, long[] b) {
        if (a.length != b.length) {
            throw new IllegalArgumentException("a.length != b.length");
        }
        long sum = 0;
        for (int i = 0; i < a.length; i++) {
            sum += a[i] * b[i];
        }
        return sum;
    }
}

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