uk.ac.ed.inf.utils
Class Utils

java.lang.Object
  uk.ac.ed.inf.utils.Utils

public class Utils
extends java.lang.Object

Various utilities to manipulate vectors of numbers, get a timestamp etc.

Version:

24-Mar-2007

Author:

Luna De Ferrari (luna.deferrari at ed.ac.uk)

Constructor Summary

Utils()

Method Summary

static double	calcAverage(double[] values) Calculates the average of the numbers in an array (from web http://forum.java.sun.com/, author JosAH)
static double	calcStandardDeviation(double[] values) Calculates the standard deviation of the elements in an array as root of the variance = [sum( x(i) - mean)^2 )] / (n-1), where x(i) is the ith element, m the mean, n the number of elements
static java.util.TreeSet<java.lang.Double>	getDoubleIntervals(java.lang.Double min, java.lang.Double max, java.lang.Double percentOfIncrement)
static boolean	getFlag(java.lang.String opt, java.lang.String[] options)
static java.util.TreeSet	getIncrements(java.lang.Object min, java.lang.Object max, java.lang.Double percentageOfIncrement) Returns a vector of numbers, starting from a minimum value, with incremental increases until the maximum value.
static java.util.TreeSet<java.lang.Integer>	getIncrementsFromRange(java.lang.Integer range, java.lang.Double percentageOfIncrement) Returns a set of increments.
static java.util.TreeSet<java.lang.Integer>	getIntegerIntervals(java.lang.Integer min, java.lang.Integer max, java.lang.Double percentageOfIncrement) Returns a vector of numbers, starting from a minimum value, with incremental increases until the maximum value.
static void	getJavaSystemProperties() Gets the Java system properties
static java.lang.String	getOption(java.lang.String opt, java.lang.String[] options) getOption(String opt, String[] options) gets an option value out of a list of options
static java.util.TreeSet<java.lang.String>	getSimpleSerie(java.lang.Double min, java.lang.Double increment, int iterations) Gets a series of doubles from a min incrementing by a given increment for a number of iterations
static void	main(java.lang.String[] argv) Main method for testing
static java.util.Properties	readLocalProperties(java.lang.String resourceName) Reads properties that inherit from three locations.
static java.util.Properties	readProperties(java.lang.String propertiesFilePath) Reads properties Code adapted from Weka: http://www.cs.waikato.ac.nz/ml/weka/ Ian H.
static double	roundDouble(double targetDouble, int decimalPlace) Rounds a number to just n decimal digits
static java.util.TreeSet<java.lang.String>	setFromObjectsToString(java.util.TreeSet<java.lang.Object> set)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Utils

public Utils()

Method Detail

calcAverage

public static double calcAverage(double[] values)

Calculates the average of the numbers in an array (from web http://forum.java.sun.com/, author JosAH)

Returns:

average of the numbers (rounded to 2 decimal digits)

calcStandardDeviation

public static double calcStandardDeviation(double[] values)

Calculates the standard deviation of the elements in an array as root of the variance = [sum( x(i) - mean)^2 )] / (n-1), where x(i) is the ith element, m the mean, n the number of elements

Returns:

standard deviation

getDoubleIntervals

public static java.util.TreeSet<java.lang.Double> getDoubleIntervals(java.lang.Double min,
                                                                     java.lang.Double max,
                                                                     java.lang.Double percentOfIncrement)

getFlag

public static boolean getFlag(java.lang.String opt,
                              java.lang.String[] options)

getIncrements

public static java.util.TreeSet getIncrements(java.lang.Object min,
                                              java.lang.Object max,
                                              java.lang.Double percentageOfIncrement)

Returns a vector of numbers, starting from a minimum value, with incremental increases until the maximum value. Example: for min 2 and max 12, percentage of increment 0.2 > [2, 4, 6, 8, 10, 12]

Parameters:

min - the minimum number value

max - the maximum number value

percentageOfIncrement - the increment as percentage of (maximum - minimum) value (the actual increment value has to be >= 1 !)

Returns:

a vector of numbers, starting from a minimum value, with incremental increases until the maximum value. Returns null if the increment is 0.

getIncrementsFromRange

public static java.util.TreeSet<java.lang.Integer> getIncrementsFromRange(java.lang.Integer range,
                                                                          java.lang.Double percentageOfIncrement)

Returns a set of increments. Example: for range 10, percentage of increment 0.2 > [0, 2, 4, 6, 8, 10]

Parameters:

range -

percentageOfIncrement -

Returns:

a set of increments

getIntegerIntervals

public static java.util.TreeSet<java.lang.Integer> getIntegerIntervals(java.lang.Integer min,
                                                                       java.lang.Integer max,
                                                                       java.lang.Double percentageOfIncrement)

Returns a vector of numbers, starting from a minimum value, with incremental increases until the maximum value.

Parameters:

min - the minimum number value

max - the maximum number value

percentageOfIncrement - the increment as percentage of (maximum - minimum) value

Returns:

a vector of numbers, starting from a minimum value, with incremental increases until the maximum value. Returns null if the increment is 0.

getJavaSystemProperties

public static void getJavaSystemProperties()

Gets the Java system properties

getOption

public static java.lang.String getOption(java.lang.String opt,
                                         java.lang.String[] options)

getOption(String opt, String[] options) gets an option value out of a list of options

Parameters:

opt - the option that needs to be extracted (e.g. -x)

options - list of options (e.g. -x 10 -y name)

Returns:

the value for the option selected (e.g. 10)

getSimpleSerie

public static java.util.TreeSet<java.lang.String> getSimpleSerie(java.lang.Double min,
                                                                 java.lang.Double increment,
                                                                 int iterations)

Gets a series of doubles from a min incrementing by a given increment for a number of iterations

Parameters:

min - the starting point

increment - the increment

iterations - the number of repetitions

Returns:

a series of doubles from a min incrementing by a given increment for a number of iterations

main

public static void main(java.lang.String[] argv)
                 throws java.lang.Exception

Main method for testing

Parameters:

argv -

Throws:

java.lang.Exception

readLocalProperties

public static java.util.Properties readLocalProperties(java.lang.String resourceName)
                                                throws java.lang.Exception

Reads properties that inherit from three locations. Code from Weka: http://www.cs.waikato.ac.nz/ml/weka/ Ian H. Witten and Eibe Frank (2005) "Data Mining: Practical machine learning tools and techniques", 2nd Edition, Morgan Kaufmann, San Francisco, 2005. Reads properties that inherit from three locations. Properties are first defined in the system resource location (i.e. in the CLASSPATH). These default properties must exist. Properties defined in the users home directory (optional) override default settings. Properties defined in the current directory (optional) override all these settings.

Parameters:

resourceName - the location of the resource that should be loaded. e.g.: "weka/core/Utils.props". (The use of hardcoded forward slashes here is OK - see jdk1.1/docs/guide/misc/resources.html) This routine will also look for the file (in this case) "Utils.props" in the users home directory and the current directory.

Returns:

the Properties

Throws:

java.lang.Exception - if no default properties are defined, or if an error occurs reading the properties files.

readProperties

public static java.util.Properties readProperties(java.lang.String propertiesFilePath)
                                           throws java.lang.Exception

Reads properties Code adapted from Weka: http://www.cs.waikato.ac.nz/ml/weka/ Ian H. Witten and Eibe Frank (2005) "Data Mining: Practical machine learning tools and techniques", 2nd Edition, Morgan Kaufmann, San Francisco, 2005.

Returns:

the Properties

Throws:

java.lang.Exception - if no default properties are defined, or if an error occurs reading the properties files.

roundDouble

public static double roundDouble(double targetDouble,
                                 int decimalPlace)

Rounds a number to just n decimal digits

Parameters:

targetDouble - the number to be rounded

decimalPlace - the number of digits to be left right of the decimal dot

Returns:

the rounded number

setFromObjectsToString

public static java.util.TreeSet<java.lang.String> setFromObjectsToString(java.util.TreeSet<java.lang.Object> set)