import java.util.Arrays;
/**
* Static methods for doing useful math
*
* @author : $Author: brian $
* @version : $Revision: 1.1 $
*
*
* The Monterey Bay Aquarium Research Institute (MBARI) provides this
* documentation and code "as is", with no warranty, express or
* implied, of its quality or consistency. It is provided without support and
* without obligation on the part of MBARI to assist in its use, correction,
* modification, or enhancement. This information should not be published or
* distributed to third parties without specific written permission from
* MBARI.
*
* Copyright 2002 MBARI.
* MBARI Proprietary Information. All rights reserved.
*
*/
public class Util{
/**
* Standard deviation is a statistical measure of spread or variability.The
* standard deviation is the root mean square (RMS) deviation of the values
* from their arithmetic mean.
*
* populationStandardDeviation normalizes values by N, where N is the sample size. This the
* Population Standard Deviation
* @param values
* @return
*/
public static strictfp double populationStandardDeviation(double[] values) {
double mean = mean(values);
double n = values.length;
double dv = 0;
for (double d : values) {
double dm = d - mean;
dv += dm * dm;
}
return Math.sqrt(dv / n);
}
/**
* Calculate the mean of an array of values
*
* @param values The values to calculate
* @return The mean of the values
*/
public static strictfp double mean(double[] values) {
return sum(values) / values.length;
}
/**
* Sum up all the values in an array
*
* @param values an array of values
* @return The sum of all values in the Array
*/
public static strictfp double sum(double[] values) {
if (values == null || values.length == 0) {
throw new IllegalArgumentException("The data array either is null or does not contain any data.");
}
else {
double sum = 0;
for (int i = 0; i < values.length; i++) {
sum += values[i];
}
return sum;
}
}
}