Computes the scalar product of two array as if they were vectors. - Java Collection Framework

Java examples for Collection Framework:Array Algorithm

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Description

Computes the scalar product of two array as if they were vectors.

Demo Code


//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        double[] w0 = new double[] { 34.45, 35.45, 36.67, 37.78, 37.0000,
                37.1234, 67.2344, 68.34534, 69.87700 };
        double[] w1 = new double[] { 34.45, 35.45, 36.67, 37.78, 37.0000,
                37.1234, 67.2344, 68.34534, 69.87700 };
        System.out.println(scalarProduct(w0, w1));
    }//from   w  w  w . j  a va2s.  com

    /**
     * Computes the scalar product of two array as if they were vectors.
     *
     * @throws IllegalArgumentException if the don't have the same length
     */
    public static double scalarProduct(double[] w0, double[] w1) {
        if (w0.length != w1.length) {
            throw new IllegalArgumentException(
                    "Arrays must have the same length : " + w0.length
                            + ", " + w1.length);
        }
        if (w0.length == 0)
            throw new IllegalArgumentException(
                    "Nothing to compute! Arrays must have at least one element.");
        double sortie = 0.0;
        for (int k = 0; k < w0.length; k++) {
            sortie += w0[k] * w1[k];
        }
        return (sortie);
    }

    /**
     * Computes the scalar product of two array as if they were matrices.
     *
     * @throws IllegalArgumentException if the don't have the same length
     */
    public static double scalarProduct(double[][] w0, double[][] w1) {
        if (w0.length != w1.length) {
            throw new IllegalArgumentException(
                    "Arrays must have the same length : " + w0.length
                            + ", " + w1.length);
        }
        if (w0.length == 0)
            throw new IllegalArgumentException(
                    "Nothing to compute! Arrays must have at least one element.");
        double sortie = 0.0;
        for (int k = 0; k < w0.length; k++) {
            sortie = sortie + scalarProduct(w0[k], w1[k]);
        }
        return (sortie);
    }

    /**
     * Computes the scalar product of two array
     * as if they were vectors.
     *
     * @throws IllegalArgumentException if the
     *                                  don't have the same length.
     */
    public static int scalarProduct(int[] w0, int[] w1) {
        if (w0.length != w1.length) {
            throw new IllegalArgumentException(
                    "Arrays must have the same length : " + w0.length
                            + ", " + w1.length);
        }
        if (w0.length == 0)
            throw new IllegalArgumentException(
                    "Nothing to compute! Arrays must have at least one element.");
        int sortie = 0;
        for (int k = 0; k < w0.length; k++) {
            sortie = sortie + w0[k] * w1[k];
        }
        return (sortie);
    }

    /**
     * Computes the scalar product of two array
     * as if they were matrices.
     *
     * @throws IllegalArgumentException if the
     *                                  don't have the same length.
     */
    public static double scalarProduct(int[][] w0, int[][] w1) {
        if (w0.length != w1.length) {
            throw new IllegalArgumentException(
                    "Arrays must have the same length : " + w0.length
                            + ", " + w1.length);
        }
        if (w0.length == 0)
            throw new IllegalArgumentException(
                    "Nothing to compute! Arrays must have at least one element.");
        double sortie = 0.0;
        for (int k = 0; k < w0.length; k++) {
            sortie = sortie + scalarProduct(w0[k], w1[k]);
        }
        return (sortie);
    }
}

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