Random Class Reference

Abstraction for a source of random or pseudorandom bits. More...

#include <geomc/random/Random.h>

Inheritance diagram for Random:

Public Member Functions
	Random (void)
	Construct a new random number generator with an implementation-selected seed.
	Random (uint64_t seed)
virtual uint32_t	rand32 ()=0
virtual void	rseed (uint64_t seed)=0
	Reset the generator's state with the bits of seed as its source of entropy. More...
template<typename T >
T	rand ()
template<typename T >
T	rand (T max)
template<typename T >
T	rand (T lo, T hi)
template<>
bool	rand ()
template<>
unsigned int	rand ()
template<>
int	rand ()
template<>
unsigned long	rand ()
template<>
long	rand ()
template<>
unsigned long long	rand ()
template<>
long long	rand ()
template<>
float	rand ()
template<>
double	rand ()
template<>
unsigned int	rand (unsigned int hi)
template<>
int	rand (int hi)
template<>
unsigned long	rand (unsigned long hi)
template<>
long	rand (long hi)
template<>
unsigned long long	rand (unsigned long long hi)
template<>
long long	rand (long long hi)
template<>
float	rand (float hi)
template<>
double	rand (double hi)
template<>
int	rand (int lo, int hi)
template<>
long long	rand (long long lo, long long hi)
template<>
float	rand (float lo, float hi)
template<>
double	rand (double lo, double hi)
template<>
bool	rand ()
template<>
unsigned int	rand ()
template<>
int	rand ()
template<>
unsigned long	rand ()
template<>
long	rand ()
template<>
unsigned long long	rand ()
template<>
long long	rand ()
template<>
float	rand ()
template<>
double	rand ()
template<>
unsigned int	rand (unsigned int hi)
template<>
int	rand (int hi)
template<>
unsigned long	rand (unsigned long hi)
template<>
long	rand (long hi)
template<>
unsigned long long	rand (unsigned long long hi)
template<>
long long	rand (long long hi)
template<>
float	rand (float hi)
template<>
double	rand (double hi)
template<>
int	rand (int lo, int hi)
template<>
long long	rand (long long lo, long long hi)
template<>
float	rand (float lo, float hi)
template<>
double	rand (double lo, double hi)

Protected Attributes
uint32_t	_bitpool
unsigned int	_bitsleft

Detailed Description

Abstraction for a source of random or pseudorandom bits.

Implementations provide random bits by overriding rand32(), which should return no fewer than 32 random bits.

Client-friendly random numbers are exposed via Random::rand<T>(). Specializations are provided for a selection of primitive T. Specializations of rand() for other T may be written, which will automatically be inherited by all subclasses of Random.

The general contract of rand() which should be followed by all specializations:

rand(void)

• If T is discrete, than this function should return values evenly over the entire space of possible T.
• If T is a continuous type, then this function should return values evenly over an analogue of the interval [0,1], inclusive.

rand(T max)

• Should return random values evenly distributed over all possible states between 0 (or the T analogue of 0) and the value of max

rand(T lo, T hi)

• Should return random values evenly distributed over all possible states bounded by lo and hi

Constructor & Destructor Documentation

Random()

Random

(

uint64_t

seed

)

Construct a new random number generator with the bits of seed as a source of entropy.

Member Function Documentation

rand() [1/24]

T rand ( void  )

inline

Produces a (pseudo-) random T with uniform distribution over the unit interval, if the unit interval is populated by T; or with uniform distribution over the entire space of possible T otherwise.

For example, rand<float>() returns a random float between 0 and 1.0, while rand<unsigned int>() returns a random uint between 0 and UINT_MAX.

rand() [2/24]

bool rand

(

)

Returns

A random boolean value.

rand() [3/24]

unsigned int rand

(

)

Returns

An unsigned int between 0 and UINT_MAX.

rand() [4/24]

int rand

(

)

Returns

An int between INT_MIN and INT_MAX.

rand() [5/24]

unsigned long rand

(

)

Returns

An unsigned long between 0 and ULONG_MAX.

rand() [6/24]

long rand

(

)

Returns

A long between LONG_MIN and LONG_MAX.

rand() [7/24]

unsigned long long rand

(

)

Returns

An unsigned long long betwen 0 and ULLONG_MAX.

rand() [8/24]

long long rand

(

)

Returns

A long long between LLONG_MIN and LLONG_MAX.

rand() [9/24]

float rand

(

)

Generate a floating-point value with uniform distribution between 0 and 1.0.

This method is preferable to use over the common practice of rand<int>() / (float)INT_MAX, as the latter excludes a large fraction of the representable floating point numbers between 0.0 and 1.0 (particularly those near zero), resulting in reduced entropy.

This method produces a number by carefully picking the bits of the exponent and mantissa explicitly, in such a way that the distibution remains uniform.

rand() [10/24]

double rand

(

)

Generate a floating-point value with uniform distribution between 0 and 1.0.

This method is preferable to use over the common practice of rand<int>() / (float)INT_MAX, as the latter excludes a large fraction of the representable floating point numbers between 0.0 and 1.0 (particularly those near zero), resulting in reduced entropy.

This method produces a number by carefully picking the bits of the exponent and mantissa explicitly, in such a way that the distibution remains uniform.

rand() [11/24]

double rand

(

double

hi

)

Parameters

hi	Upper or lower bound of random number.

Returns

A double between 0 and hi, regardless of the sign of hi.

rand() [12/24]

double rand	(	double	lo,
		double	hi
	)

Parameters

lo	Lower bound of random number.
hi	Upper bound of random number.

Returns

An double between lo and hi.

rand() [13/24]

float rand

(

float

hi

)

Parameters

hi	Upper or lower bound of random number.

Returns

A float between 0 and hi, regardless of the sign of hi.

rand() [14/24]

float rand	(	float	lo,
		float	hi
	)

Parameters

lo	Lower bound of random number.
hi	Upper bound of random number.

Returns

An float between lo and hi.

rand() [15/24]

int rand

(

int

hi

)

Parameters

hi	Upper or lower bound of random number.

Returns

A number between 0 and hi (regardless of the sign of hi).

rand() [16/24]

int rand	(	int	lo,
		int	hi
	)

Parameters

lo	Lower bound of random number.
hi	Upper bound of random number.

Returns

An int between lo and hi.

rand() [17/24]

long rand

(

long

hi

)

Parameters

hi	Upper or lower bound of random number.

Returns

A long between 0 and hi, regardless of the sign of hi.

rand() [18/24]

long long rand

(

long long

hi

)

Parameters

hi	Upper or lower bound of random number.

Returns

A long long between 0 and hi, regardless of the sign of hi.

rand() [19/24]

long long rand	(	long long	lo,
		long long	hi
	)

Parameters

lo	Lower bound of random number.
hi	Upper bound of random number.

Returns

A long long between lo and hi.

rand() [20/24]

T rand ( T  lo, T  hi  )

inline

Produces a (pseudo-) random T with uniform distribution between lo and hi.

Parameters

lo	Lower bound for possible T samples.
hi	Upper bound for possible T samples.

rand() [21/24]

T rand ( T  max )

inline

Produces a (pseudo-) random T with uniform distribution between the T analogue of 0 and max.

Parameters

max	Upper bound of possible T samples.

rand() [22/24]

unsigned int rand

(

unsigned int

hi

)

Parameters

hi	Upper bound of random number.

Returns

An unsigned int between 0 and hi.

rand() [23/24]

unsigned long rand

(

unsigned long

hi

)

Parameters

hi	Upper bound of random number.

Returns

An unsigned long between 0 and hi.

rand() [24/24]

unsigned long long rand

(

unsigned long long

hi

)

Parameters

hi	Upper bound of random number.

Returns

An unsigned long long between 0 and hi.

rand32()

virtual uint32_t rand32 ( )

pure virtual

Returns

No fewer than 32 (pseudo-) random bits.

Implemented in LCRand, MTRand, and XoshiroRand.

rseed()

virtual void rseed ( uint64_t  seed )

pure virtual

Reset the generator's state with the bits of seed as its source of entropy.

Implemented in LCRand, MTRand, and XoshiroRand.

---

The documentation for this class was generated from the following files:

• geomc/random/Random.h
• geomc/random/Random.cpp
• geomc/random/randomdetail/RandomSpecialize.h