imagingbook.lib.math.Statistics.java Source code

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Here is the source code for imagingbook.lib.math.Statistics.java

Source

/*******************************************************************************
 This software is provided as a supplement to the authors' textbooks on digital
 image processing published by Springer-Verlag in various languages and editions.
 Permission to use and distribute this software is granted under the BSD 2-Clause 
 "Simplified" License (see http://opensource.org/licenses/BSD-2-Clause). 
 Copyright (c) 2006-2013 Wilhelm Burger, Mark J. Burge. 
 All rights reserved. Visit http://www.imagingbook.com for additional details.
 ******************************************************************************/

package imagingbook.lib.math;

import org.apache.commons.math3.stat.correlation.Covariance;

public class Statistics {

    public static double[][] covarianceMatrix(double[][] samples) {
        Covariance sm = new Covariance(samples);
        return sm.getCovarianceMatrix().getData();
    }

    //   public static void main(String[] args) {
    //      // example from UTICS-C Appendix:
    //      // n = 4 samples
    //      // m = 3 dimensions
    //      double[][] samples = { // samples[i][j], i = column index, j = row index.
    //            {75, 37, 12},   // i = 0
    //            {41, 27, 20},   // i = 1
    //            {93, 81, 11},   // i = 2
    //            {12, 48, 52}   // i = 3
    //      };
    //      
    //      // covariance matrix Cov (3x3)
    //      double[][] cov = covarianceMatrix(samples);
    //      System.out.println("cov = " + Matrix.toString(cov));
    //      
    //      System.out.println();
    //      
    //      double[][] icov = Matrix.inverse(cov);
    //      System.out.println("icov = " + Matrix.toString(icov));
    //   }

}