org.conqat.lib.commons.math

Class MathUtils

java.lang.Object

org.conqat.lib.commons.math.MathUtils

public class MathUtils
extends java.lang.Object

Collection of math utility methods.

Constructor Summary

Constructors

Constructor and Description
MathUtils()

Method Summary

Modifier and Type	Method and Description
static double	aggregate(java.util.Collection<? extends java.lang.Number> values, EAggregationStrategy aggregation) Aggregate collections of values with a given aggregation strategy.
static int	choose(long n, long k) Calculates the number of choices for k from n elements, also known as binomial coefficients.
static double	constrainValue(double value, double min, double max) Constrains the given value, if it exceeds the given minimum or maximum.
static int	constrainValue(int value, int min, int max) Constrains the given value, if it exceeds the given minimum or maximum.
static long	factorial(int n) Computes the factorial of n.
static boolean	isNormal(double number) Checks if the provided number is neither infinite nor NaN.
static double	max(java.util.Collection<? extends java.lang.Number> collection) Find maximum.
static double	mean(java.util.Collection<? extends java.lang.Number> collection) Find mean.
static double	median(java.util.Collection<? extends java.lang.Number> collection) Find median.
static double	min(java.util.Collection<? extends java.lang.Number> collection) Find minimum.
static double	percentile25(java.util.Collection<? extends java.lang.Number> collection) Find the 25-percentile.
static double	percentile75(java.util.Collection<? extends java.lang.Number> collection) Find the 75-percentile.
static void	printBasicDescriptiveStatistics(java.util.Collection<? extends java.lang.Number> values) Prints the min, max, mean, percentile25, median, and percentile75 of the given values to System.out.
static void	printBasicDescriptiveStatistics(java.util.Collection<? extends java.lang.Number> values, java.io.PrintStream printStream) Prints the min, max, sum, mean, percentile25, median, and percentile75 of the given values to the given PrintStream.
static CounterSet<Range>	rangeDistribution(java.util.List<java.lang.Double> values, java.util.Set<Range> ranges) Computes a distribution of the given list of values and the given ranges.
static double	stdDev(java.util.Collection<? extends java.lang.Number> collection, boolean sample) Calculate standard deviation of the data set.
static double	sum(java.util.Collection<? extends java.lang.Number> collection) Sum values.
static double	variance(java.util.Collection<? extends java.lang.Number> collection, boolean sample) Calculate variance of the data set.

Methods inherited from class java.lang.Object

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

Constructor Detail

MathUtils

public MathUtils()

Method Detail

sum

public static double sum(java.util.Collection<? extends java.lang.Number> collection)

Sum values.

See Also:

SumAggregator, EAggregationStrategy.SUM

max

public static double max(java.util.Collection<? extends java.lang.Number> collection)

Find maximum.

See Also:

MaxAggregator, EAggregationStrategy.MAX

min

public static double min(java.util.Collection<? extends java.lang.Number> collection)

Find minimum.

See Also:

MinAggregator, EAggregationStrategy.MIN

mean

public static double mean(java.util.Collection<? extends java.lang.Number> collection)

Find mean.

Returns:

Double.NaN for empty input collection

See Also:

MeanAggregator, EAggregationStrategy.MEAN

median

public static double median(java.util.Collection<? extends java.lang.Number> collection)

Find median.

Returns:

Double.NaN for empty input collection

See Also:

PercentileAggregator, EAggregationStrategy.MEDIAN

percentile25

public static double percentile25(java.util.Collection<? extends java.lang.Number> collection)

Find the 25-percentile.

Returns:

Double.NaN for empty input collection

See Also:

PercentileAggregator, EAggregationStrategy.MEDIAN

percentile75

public static double percentile75(java.util.Collection<? extends java.lang.Number> collection)

Find the 75-percentile.

Returns:

Double.NaN for empty input collection

See Also:

PercentileAggregator, EAggregationStrategy.MEDIAN

variance

public static double variance(java.util.Collection<? extends java.lang.Number> collection,
                              boolean sample)

Calculate variance of the data set.

Parameters:

sample - if true sample variance is calculated, population variance otherwise

stdDev

public static double stdDev(java.util.Collection<? extends java.lang.Number> collection,
                            boolean sample)

Calculate standard deviation of the data set.

Parameters:

sample - if true sample standard deviation is calculated, population variance otherwise

aggregate

public static double aggregate(java.util.Collection<? extends java.lang.Number> values,
                               EAggregationStrategy aggregation)

Aggregate collections of values with a given aggregation strategy.

Returns:

certain aggregation strategies may return Double.NaN for empty input collections

factorial

public static long factorial(int n)

Computes the factorial of n. Errors are not handled. If n is negative, 1 will be returned. If n to too large, wrong results will be produced due to numerical overflow.

isNormal

public static boolean isNormal(double number)

Checks if the provided number is neither infinite nor NaN.

choose

public static int choose(long n,
                         long k)

Calculates the number of choices for k from n elements, also known as binomial coefficients. The input parameters may not be too large to avoid overflows. Both parameters must be non-negative.

rangeDistribution

public static CounterSet<Range> rangeDistribution(java.util.List<java.lang.Double> values,
                                                  java.util.Set<Range> ranges)

Computes a distribution of the given list of values and the given ranges. The result is a counter set of ranges, denoting how many values in the list are within a given range.

It is not checked whether the ranges are disjoint. Moreover, it is not checked whether every value can be mapped to a range. Thus, the resulting counter set may have an overall value that is less than or greater than the size of the list of given values.

printBasicDescriptiveStatistics

public static void printBasicDescriptiveStatistics(java.util.Collection<? extends java.lang.Number> values)

Prints the min, max, mean, percentile25, median, and percentile75 of the given values to System.out.

printBasicDescriptiveStatistics

public static void printBasicDescriptiveStatistics(java.util.Collection<? extends java.lang.Number> values,
                                                   java.io.PrintStream printStream)

Prints the min, max, sum, mean, percentile25, median, and percentile75 of the given values to the given PrintStream.

constrainValue

public static int constrainValue(int value,
                                 int min,
                                 int max)

Constrains the given value, if it exceeds the given minimum or maximum.

Returns:

the given value, if it is within the given minimum and maximum (inclusive) or the minimum or maximum respectively, if it exceeds these.

constrainValue

public static double constrainValue(double value,
                                    double min,
                                    double max)

Constrains the given value, if it exceeds the given minimum or maximum.

Returns:

the given value, if it is within the given minimum and maximum (inclusive) or the minimum or maximum respectively, if it exceeds these.