public final class Functions
extends java.lang.Object
Modifier and Type | Field and Description |
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static int |
WITH_REPLACEMENT |
static int |
WITHOUT_REPLACEMENT |
Constructor and Description |
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Functions() |
Modifier and Type | Method and Description |
---|---|
static double |
beta(double a,
double b)
This method returns an approximation to the beta function.
|
static double |
betaCDF(double x,
double a,
double b)
The method computes the beta cumulative distribution function.
|
static double |
comb(double n,
int k)
This method computes the number of combinations of a specified number of
objects chosen from a population of a specified size.
|
static double |
factorial(int k)
This method computes the factorial function, the number of permutations
of a specified number of objects.
|
static double |
gamma(double x)
This method computes the gamma function.
|
static double |
gammaCDF(double x,
double a)
This method computes the cumulative distribution function of the gamma
distribution with a specified shape parameter and scale parameter 1.
|
static int |
getIndex(int i,
int n)
This method returns an index between 0 and n - 1, for use in error
correcting in arrays.
|
static double[] |
getProbabilities(double[] a)
This method takes an array of numbers and returns a probability array
(nonnegatie numbers that sum to 1).
|
static double |
getProbability(double p)
This method takes a real number and converts it to a probability (a
number between 0 and 1).
|
static int[] |
getSample(int[] p,
int n,
int t)
This method computes a sample of a specified size from a specified
population and of a specified type (with or without replacement).
|
static int[] |
getSample(int m,
int n,
int t)
This method computes a sample of a specified size from a population of
the form 1, 2, ..., m
|
static boolean |
isReal(double x)
This class method tests to see if a specified number is real.
|
static double |
logGamma(double x)
This method computes the log of the gamma function.
|
static double |
perm(double n,
int k)
This method computes the number of permuatations of a specified number of
objects chosen from a population of a specified number of objects.
|
static double[] |
sort(double[] a)
This method sorts an array of doubles.
|
static int[] |
sort(int[] a)
This method sorts an array of integers.
|
public static final int WITHOUT_REPLACEMENT
public static final int WITH_REPLACEMENT
public static double[] getProbabilities(double[] a)
a
- the array of numberspublic static double getProbability(double p)
p
- the given numberpublic static int getIndex(int i, int n)
i
- the given indexn
- the specified size of the arraypublic static double perm(double n, int k)
n
- the population sizek
- the sample sizepublic static double factorial(int k)
k
- the number of objectspublic static double comb(double n, int k)
n
- the population sizek
- the sample sizepublic static double logGamma(double x)
x
- a positive numberpublic static double gamma(double x)
x
- a positive numberpublic static double gammaCDF(double x, double a)
x
- a positive numbera
- the shape parameterpublic static double betaCDF(double x, double a, double b)
x
- a number between 0 and 1a
- the left paramterb
- the right parameterpublic static double beta(double a, double b)
a
- the left valueb
- the right valuepublic static int[] getSample(int[] p, int n, int t)
p
- the populationn
- the sample sizet
- the type (0 without replacement, 1 with replacemen);public static int[] getSample(int m, int n, int t)
m
- the population sizen
- the sample sizet
- the type (0 without replacement, 1 with replacement)public static double[] sort(double[] a)
a
- the array of doublespublic static int[] sort(int[] a)
a
- the array of integerspublic static boolean isReal(double x)
x
- the number