Apache Commons Math 3.6.1 · org.apache.commons.math3.random.RandomData

Method Summary

Modifier and Type	Method and Description
public double	Returns: a random value following the specified exponential distribution nextExponential(double the mean of the distribution mean) Generates a random value from the exponential distribution with specified mean.
public double	Returns: a random value following the specified Gaussian distribution nextGaussian(double the mean of the distribution mu, double the standard deviation of the distribution sigma) Generates a random value from the Normal (or Gaussian) distribution with specified mean and standard deviation.
public String	Returns: a random string of hex characters of length `len` nextHexString(int the length of the string to be generated len) Generates a random string of hex characters of length `len`.
public int	Returns: a random integer greater than or equal to `lower` and less than or equal to `upper` nextInt(int lower bound for generated integer lower, int upper bound for generated integer upper) Generates a uniformly distributed random integer between `lower` and `upper` (endpoints included).
public long	Returns: a random long integer greater than or equal to `lower` and less than or equal to `upper` nextLong(long lower bound for generated long integer lower, long upper bound for generated long integer upper) Generates a uniformly distributed random long integer between `lower` and `upper` (endpoints included).
public int[]	Returns: a random `k`-permutation of `n`, as an array of integers nextPermutation(int the domain of the permutation n, int the size of the permutation k) Generates an integer array of length `k` whose entries are selected randomly, without repetition, from the integers `0, ..., n - 1` (inclusive).
public long	Returns: a random value following the specified Poisson distribution nextPoisson(double the mean of the Poisson distribution mean) Generates a random value from the Poisson distribution with the given mean.
public Object[]	Returns: a random sample of `k` elements from `c` nextSample(Collection<?> the collection to be sampled c, int the size of the sample k) Returns an array of `k` objects selected randomly from the Collection `c`.
public String	Returns: a random string of hex characters of length `len` nextSecureHexString(int the length of the string to be generated len) Generates a random string of hex characters from a secure random sequence.
public int	Returns: a random integer greater than or equal to `lower` and less than or equal to `upper`. nextSecureInt(int lower bound for generated integer lower, int upper bound for generated integer upper) Generates a uniformly distributed random integer between `lower` and `upper` (endpoints included) from a secure random sequence.
public long	Returns: a random long integer greater than or equal to `lower` and less than or equal to `upper`. nextSecureLong(long lower bound for generated integer lower, long upper bound for generated integer upper) Generates a uniformly distributed random long integer between `lower` and `upper` (endpoints included) from a secure random sequence.
public double	Returns: a uniformly distributed random value between lower and upper (exclusive) nextUniform(double the exclusive lower bound of the support lower, double the exclusive upper bound of the support upper) Generates a uniformly distributed random value from the open interval `(lower, upper)` (i.e., endpoints excluded).
public double	Returns: uniformly distributed random value in the `(lower, upper)` interval, if `lowerInclusive` is `false`, or in the `[lower, upper)` interval, if `lowerInclusive` is `true` nextUniform(double the lower bound of the support lower, double the exclusive upper bound of the support upper, boolean `true` if the lower bound is inclusive lowerInclusive) Generates a uniformly distributed random value from the interval `(lower, upper)` or the interval `[lower, upper)`.

Method Detail

nextExponential back to summary

nextExponential	back to summary
public double nextExponential(double mean) throws NotStrictlyPositiveException Generates a random value from the exponential distribution with specified mean. Definition: Exponential Distribution Parameters mean:double the mean of the distribution Returns:double a random value following the specified exponential distribution Exceptions NotStrictlyPositiveException: if `mean <= 0`.

public double nextExponential(double mean) throws NotStrictlyPositiveException

Generates a random value from the exponential distribution with specified mean.

Definition: Exponential Distribution

Parameters

mean:double: the mean of the distribution

Returns:double

a random value following the specified exponential distribution

Exceptions

NotStrictlyPositiveException:: if mean <= 0.

nextGaussian back to summary

nextGaussian	back to summary
public double nextGaussian(double mu, double sigma) throws NotStrictlyPositiveException Generates a random value from the Normal (or Gaussian) distribution with specified mean and standard deviation. Definition: Normal Distribution Parameters mu:double the mean of the distribution sigma:double the standard deviation of the distribution Returns:double a random value following the specified Gaussian distribution Exceptions NotStrictlyPositiveException: if `sigma <= 0`.

public double nextGaussian(double mu, double sigma) throws NotStrictlyPositiveException

Generates a random value from the Normal (or Gaussian) distribution with specified mean and standard deviation.

Definition: Normal Distribution

Parameters

mu:double: the mean of the distribution
sigma:double: the standard deviation of the distribution

Returns:double

a random value following the specified Gaussian distribution

Exceptions

NotStrictlyPositiveException:: if sigma <= 0.

nextHexString back to summary

nextHexString	back to summary
public String nextHexString(int len) throws NotStrictlyPositiveException Generates a random string of hex characters of length `len`. The generated string will be random, but not cryptographically secure. To generate cryptographically secure strings, use `nextSecureHexString(int)`. Parameters len:int the length of the string to be generated Returns:String a random string of hex characters of length `len` Exceptions NotStrictlyPositiveException: if `len <= 0`

public String nextHexString(int len) throws NotStrictlyPositiveException

Generates a random string of hex characters of length len.

The generated string will be random, but not cryptographically secure. To generate cryptographically secure strings, use nextSecureHexString(int).

Parameters

len:int: the length of the string to be generated

Returns:String

a random string of hex characters of length len

Exceptions

NotStrictlyPositiveException:: if len <= 0

nextInt back to summary

nextInt	back to summary
public int nextInt(int lower, int upper) throws NumberIsTooLargeException Generates a uniformly distributed random integer between `lower` and `upper` (endpoints included). The generated integer will be random, but not cryptographically secure. To generate cryptographically secure integer sequences, use `nextSecureInt(int, int)`. Parameters lower:int lower bound for generated integer upper:int upper bound for generated integer Returns:int a random integer greater than or equal to `lower` and less than or equal to `upper` Exceptions NumberIsTooLargeException: if `lower >= upper`

public int nextInt(int lower, int upper) throws NumberIsTooLargeException

Generates a uniformly distributed random integer between lower and upper (endpoints included).

The generated integer will be random, but not cryptographically secure. To generate cryptographically secure integer sequences, use nextSecureInt(int, int).

Parameters

lower:int: lower bound for generated integer
upper:int: upper bound for generated integer

Returns:int

a random integer greater than or equal to lower and less than or equal to upper

Exceptions

NumberIsTooLargeException:: if lower >= upper

nextLong back to summary

nextLong	back to summary
public long nextLong(long lower, long upper) throws NumberIsTooLargeException Generates a uniformly distributed random long integer between `lower` and `upper` (endpoints included). The generated long integer values will be random, but not cryptographically secure. To generate cryptographically secure sequences of longs, use `nextSecureLong(long, long)`. Parameters lower:long lower bound for generated long integer upper:long upper bound for generated long integer Returns:long a random long integer greater than or equal to `lower` and less than or equal to `upper` Exceptions NumberIsTooLargeException: if `lower >= upper`

public long nextLong(long lower, long upper) throws NumberIsTooLargeException

Generates a uniformly distributed random long integer between lower and upper (endpoints included).

The generated long integer values will be random, but not cryptographically secure. To generate cryptographically secure sequences of longs, use nextSecureLong(long, long).

Parameters

lower:long: lower bound for generated long integer
upper:long: upper bound for generated long integer

Returns:long

a random long integer greater than or equal to lower and less than or equal to upper

Exceptions

NumberIsTooLargeException:: if lower >= upper

nextPermutation back to summary

nextPermutation	back to summary
public int[] nextPermutation(int n, int k) throws NumberIsTooLargeException, NotStrictlyPositiveException Generates an integer array of length `k` whose entries are selected randomly, without repetition, from the integers `0, ..., n - 1` (inclusive). Generated arrays represent permutations of `n` taken `k` at a time. Parameters n:int the domain of the permutation k:int the size of the permutation Returns:int[] a random `k`-permutation of `n`, as an array of integers Exceptions NumberIsTooLargeException: if `k > n`. NotStrictlyPositiveException: if `k <= 0`.

public int[] nextPermutation(int n, int k) throws NumberIsTooLargeException, NotStrictlyPositiveException

Generates an integer array of length k whose entries are selected randomly, without repetition, from the integers 0, ..., n - 1 (inclusive).

Generated arrays represent permutations of n taken k at a time.

Parameters

n:int: the domain of the permutation
k:int: the size of the permutation

Returns:int[]

a random k-permutation of n, as an array of integers

Exceptions

NumberIsTooLargeException:: if k > n.
NotStrictlyPositiveException:: if k <= 0.

nextPoisson back to summary

nextPoisson	back to summary
public long nextPoisson(double mean) throws NotStrictlyPositiveException Generates a random value from the Poisson distribution with the given mean. Definition: Poisson Distribution Parameters mean:double the mean of the Poisson distribution Returns:long a random value following the specified Poisson distribution Exceptions NotStrictlyPositiveException: if `mean <= 0`.

public long nextPoisson(double mean) throws NotStrictlyPositiveException

Generates a random value from the Poisson distribution with the given mean.

Definition: Poisson Distribution

Parameters

mean:double: the mean of the Poisson distribution

Returns:long

a random value following the specified Poisson distribution

Exceptions

NotStrictlyPositiveException:: if mean <= 0.

nextSample back to summary

nextSample	back to summary
public Object[] nextSample(Collection<?> c, int k) throws NumberIsTooLargeException, NotStrictlyPositiveException Returns an array of `k` objects selected randomly from the Collection `c`. Sampling from `c` is without replacement; but if `c` contains identical objects, the sample may include repeats. If all elements of `c` are distinct, the resulting object array represents a Simple Random Sample of size `k` from the elements of `c`. Parameters c:Collection<?> the collection to be sampled k:int the size of the sample Returns:Object[] a random sample of `k` elements from `c` Exceptions NumberIsTooLargeException: if `k > c.size()`. NotStrictlyPositiveException: if `k <= 0`.

public Object[] nextSample(Collection<?> c, int k) throws NumberIsTooLargeException, NotStrictlyPositiveException

Returns an array of k objects selected randomly from the Collection c.

Sampling from c is without replacement; but if c contains identical objects, the sample may include repeats. If all elements of c are distinct, the resulting object array represents a Simple Random Sample of size k from the elements of c.

Parameters

c:Collection<?>: the collection to be sampled
k:int: the size of the sample

Returns:Object[]

a random sample of k elements from c

Exceptions

NumberIsTooLargeException:: if k > c.size().
NotStrictlyPositiveException:: if k <= 0.

nextSecureHexString back to summary

nextSecureHexString	back to summary
public String nextSecureHexString(int len) throws NotStrictlyPositiveException Generates a random string of hex characters from a secure random sequence. If cryptographic security is not required, use `nextHexString(int)`. Parameters len:int the length of the string to be generated Returns:String a random string of hex characters of length `len` Exceptions NotStrictlyPositiveException: if `len <= 0`

public String nextSecureHexString(int len) throws NotStrictlyPositiveException

Generates a random string of hex characters from a secure random sequence.

If cryptographic security is not required, use nextHexString(int).

Parameters

len:int: the length of the string to be generated

Returns:String

a random string of hex characters of length len

Exceptions

NotStrictlyPositiveException:: if len <= 0

nextSecureInt back to summary

nextSecureInt	back to summary
public int nextSecureInt(int lower, int upper) throws NumberIsTooLargeException Generates a uniformly distributed random integer between `lower` and `upper` (endpoints included) from a secure random sequence. Sequences of integers generated using this method will be cryptographically secure. If cryptographic security is not required, `nextInt(int, int)` should be used instead of this method. Definition: Secure Random Sequence Parameters lower:int lower bound for generated integer upper:int upper bound for generated integer Returns:int a random integer greater than or equal to `lower` and less than or equal to `upper`. Exceptions NumberIsTooLargeException: if `lower >= upper`.

public int nextSecureInt(int lower, int upper) throws NumberIsTooLargeException

Generates a uniformly distributed random integer between lower and upper (endpoints included) from a secure random sequence.

Sequences of integers generated using this method will be cryptographically secure. If cryptographic security is not required, nextInt(int, int) should be used instead of this method.

Definition: Secure Random Sequence

Parameters

lower:int: lower bound for generated integer
upper:int: upper bound for generated integer

Returns:int

a random integer greater than or equal to lower and less than or equal to upper.

Exceptions

NumberIsTooLargeException:: if lower >= upper.

nextSecureLong back to summary

nextSecureLong	back to summary
public long nextSecureLong(long lower, long upper) throws NumberIsTooLargeException Generates a uniformly distributed random long integer between `lower` and `upper` (endpoints included) from a secure random sequence. Sequences of long values generated using this method will be cryptographically secure. If cryptographic security is not required, `nextLong(long, long)` should be used instead of this method. Definition: Secure Random Sequence Parameters lower:long lower bound for generated integer upper:long upper bound for generated integer Returns:long a random long integer greater than or equal to `lower` and less than or equal to `upper`. Exceptions NumberIsTooLargeException: if `lower >= upper`.

public long nextSecureLong(long lower, long upper) throws NumberIsTooLargeException

Generates a uniformly distributed random long integer between lower and upper (endpoints included) from a secure random sequence.

Sequences of long values generated using this method will be cryptographically secure. If cryptographic security is not required, nextLong(long, long) should be used instead of this method.

Definition: Secure Random Sequence

Parameters

lower:long: lower bound for generated integer
upper:long: upper bound for generated integer

Returns:long

a random long integer greater than or equal to lower and less than or equal to upper.

Exceptions

NumberIsTooLargeException:: if lower >= upper.

nextUniform back to summary

nextUniform	back to summary
public double nextUniform(double lower, double upper) throws NumberIsTooLargeException, NotFiniteNumberException, NotANumberException Generates a uniformly distributed random value from the open interval `(lower, upper)` (i.e., endpoints excluded). Definition: Uniform Distribution `lower` and `upper - lower` are the location and scale parameters, respectively. Parameters lower:double the exclusive lower bound of the support upper:double the exclusive upper bound of the support Returns:double a uniformly distributed random value between lower and upper (exclusive) Exceptions NumberIsTooLargeException: if `lower >= upper` NotFiniteNumberException: if one of the bounds is infinite NotANumberException: if one of the bounds is NaN

public double nextUniform(double lower, double upper) throws NumberIsTooLargeException, NotFiniteNumberException, NotANumberException

Generates a uniformly distributed random value from the open interval (lower, upper) (i.e., endpoints excluded).

Definition: Uniform Distribution lower and upper - lower are the location and scale parameters, respectively.

Parameters

lower:double: the exclusive lower bound of the support
upper:double: the exclusive upper bound of the support

Returns:double

a uniformly distributed random value between lower and upper (exclusive)

Exceptions

NumberIsTooLargeException:: if lower >= upper
NotFiniteNumberException:: if one of the bounds is infinite
NotANumberException:: if one of the bounds is NaN

nextUniform back to summary

nextUniform	back to summary
public double nextUniform(double lower, double upper, boolean lowerInclusive) throws NumberIsTooLargeException, NotFiniteNumberException, NotANumberException Generates a uniformly distributed random value from the interval `(lower, upper)` or the interval `[lower, upper)`. The lower bound is thus optionally included, while the upper bound is always excluded. Definition: Uniform Distribution `lower` and `upper - lower` are the location and scale parameters, respectively. Parameters lower:double the lower bound of the support upper:double the exclusive upper bound of the support lowerInclusive:boolean `true` if the lower bound is inclusive Returns:double uniformly distributed random value in the `(lower, upper)` interval, if `lowerInclusive` is `false`, or in the `[lower, upper)` interval, if `lowerInclusive` is `true` Exceptions NumberIsTooLargeException: if `lower >= upper` NotFiniteNumberException: if one of the bounds is infinite NotANumberException: if one of the bounds is NaN

public double nextUniform(double lower, double upper, boolean lowerInclusive) throws NumberIsTooLargeException, NotFiniteNumberException, NotANumberException

Generates a uniformly distributed random value from the interval (lower, upper) or the interval [lower, upper). The lower bound is thus optionally included, while the upper bound is always excluded.

Definition: Uniform Distribution lower and upper - lower are the location and scale parameters, respectively.

Parameters

lower:double: the lower bound of the support
upper:double: the exclusive upper bound of the support
lowerInclusive:boolean: true if the lower bound is inclusive

Returns:double

uniformly distributed random value in the (lower, upper) interval, if lowerInclusive is false, or in the [lower, upper) interval, if lowerInclusive is true

Exceptions

NumberIsTooLargeException:: if lower >= upper
NotFiniteNumberException:: if one of the bounds is infinite
NotANumberException:: if one of the bounds is NaN

public Interface RandomData

Method Summary

Method Detail