Package com.gengoai.math

Class Math2

java.lang.Object

com.gengoai.math.Math2

public final class Math2
extends Object

Commonly needed math routines and methods that work over arrays and iterable.

Author:

David B. Bracewell

Field Summary

Fields

Modifier and Type	Field	Description
static double	LOG_2	The constant LOG_2.

Method Summary

Modifier and Type	Method	Description
static double	auc(double[] x, double[] y)	Calculates the AUC (Area Under the Curve)
static double	clip(double value, double min, double max)	Clips a value to ensure it falls between the lower or upper bound of range.
static double	log2(double number)	Calculates the base 2 log of a given number
static <E> E	maxBy(E e1, E e2, Comparator<E> comparator)
static <E> E	minBy(E e1, E e2, Comparator<E> comparator)
static double	rescale(double value, double originalMin, double originalMax, double newMin, double newMax)	Rescales a value from an old range to a new range, e.g.
static double	safeLog(double d)	Safe log double.
static double	sum(double... values)	Sums the numbers in the given array.
static int	sum(int... values)	Sums the numbers in the given array.
static long	sum(long... values)	Sums the numbers in the given array.
static double	sum(Iterable<? extends Number> values)	Sums the numbers in a given iterable treating them as doubles.
static EnhancedDoubleStatistics	summaryStatistics(double... values)	Calculates the summary statistics for the values in the given array.
static EnhancedDoubleStatistics	summaryStatistics(int... values)	Calculates the summary statistics for the values in the given array.
static EnhancedDoubleStatistics	summaryStatistics(long... values)	Calculates the summary statistics for the values in the given array.
static EnhancedDoubleStatistics	summaryStatistics(Iterable<? extends Number> values)	Calculates the summary statistics for the values in the given iterable.
static Double	tryParseDouble(String string)	Try to parse a string into a double returning null if a parse error occurs
static Float	tryParseFloat(String string)	Try to parse a string into a float returning null if a parse error occurs
static Integer	tryParseInteger(String string)	Try to parse a string into a integer returning null if a parse error occurs
static Long	tryParseLong(String string)	Try to parse a string into a long returning null if a parse error occurs

Methods inherited from class java.lang.Object

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

Field Detail

LOG_2

public static final double LOG_2

The constant LOG_2.

Method Detail

auc

public static double auc(double[] x,
                         double[] y)

Calculates the AUC (Area Under the Curve)

Parameters:

x - the x

y - the y

Returns:

the AUC

clip

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

Clips a value to ensure it falls between the lower or upper bound of range.

Parameters:

value - the value to clip

min - the lower bound of the range

max - the upper bound of the range

Returns:

the clipped value

log2

public static double log2(double number)

Calculates the base 2 log of a given number

Parameters:

number - the number to calculate the base 2 log of

Returns:

the base 2 log of the given number

maxBy

public static <E> E maxBy(E e1,
                          E e2,
                          Comparator<E> comparator)

minBy

public static <E> E minBy(E e1,
                          E e2,
                          Comparator<E> comparator)

rescale

public static double rescale(double value,
                             double originalMin,
                             double originalMax,
                             double newMin,
                             double newMax)

Rescales a value from an old range to a new range, e.g. change the value 2 in a 1 to 5 scale to the value 3.25 in a 1 to 10 scale

Parameters:

value - the value to rescale

originalMin - the lower bound of the original range

originalMax - the upper bound of the original range

newMin - the lower bound of the new range

newMax - the upper bound of the new range

Returns:

the given value rescaled to fall between newMin and new Max

Throws:

IllegalArgumentException - if originalMax <= originalMin or newMax <= newMin

safeLog

public static double safeLog(double d)

Safe log double.

Parameters:

d - the d

Returns:

the double

sum

public static double sum(Iterable<? extends Number> values)

Sums the numbers in a given iterable treating them as doubles.

Parameters:

values - the iterable of numbers to sum

Returns:

the sum of the iterable

Throws:

NullPointerException - if the values are null

sum

public static double sum(double... values)

Sums the numbers in the given array.

Parameters:

values - the values to sum

Returns:

the sum of the values

Throws:

NullPointerException - if the values are null

sum

public static int sum(int... values)

Sums the numbers in the given array.

Parameters:

values - the values to sum

Returns:

the sum of the values

Throws:

NullPointerException - if the values are null

sum

public static long sum(long... values)

Sums the numbers in the given array.

Parameters:

values - the values to sum

Returns:

the sum of the values

Throws:

NullPointerException - if the values are null

summaryStatistics

public static EnhancedDoubleStatistics summaryStatistics(double... values)

Calculates the summary statistics for the values in the given array.

Parameters:

values - the values to calculate summary statistics over

Returns:

the summary statistics of the given array

Throws:

NullPointerException - if the values are null

summaryStatistics

public static EnhancedDoubleStatistics summaryStatistics(int... values)

Calculates the summary statistics for the values in the given array.

Parameters:

values - the values to calculate summary statistics over

Returns:

the summary statistics of the given array

Throws:

NullPointerException - if the values are null

summaryStatistics

public static EnhancedDoubleStatistics summaryStatistics(long... values)

Calculates the summary statistics for the values in the given array.

Parameters:

values - the values to calculate summary statistics over

Returns:

the summary statistics of the given array

Throws:

NullPointerException - if the values are null

summaryStatistics

public static EnhancedDoubleStatistics summaryStatistics(Iterable<? extends Number> values)

Calculates the summary statistics for the values in the given iterable.

Parameters:

values - the values to calculate summary statistics over

Returns:

the summary statistics of the given iterable

Throws:

NullPointerException - if the iterable is null

tryParseDouble

public static Double tryParseDouble(String string)

Try to parse a string into a double returning null if a parse error occurs

Parameters:

string - the string to parse

Returns:

the parsed Double value or null if not parsable

tryParseFloat

public static Float tryParseFloat(String string)

Try to parse a string into a float returning null if a parse error occurs

Parameters:

string - the string to parse

Returns:

the parsed Float value or null if not parsable

tryParseInteger

public static Integer tryParseInteger(String string)

Try to parse a string into a integer returning null if a parse error occurs

Parameters:

string - the string to parse

Returns:

the parsed Integer value or null if not parsable

tryParseLong

public static Long tryParseLong(String string)

Try to parse a string into a long returning null if a parse error occurs

Parameters:

string - the string to parse

Returns:

the parsed long value or null if not parsable