The wrapper class for gsl's random number generater. More...

#include <randnum.h>

Collaboration diagram for EMAN::Randnum:

Public Member Functions
void	set_seed (unsigned long long seed)
	Set the seed for the random number generator. More...

unsigned long long	get_seed ()
	Get the current random number seed. More...

long long	get_irand (long long lo, long long hi) const
	This function returns a random integer from lo to hi inclusive. More...

float	get_frand (double lo=0.0, double hi=1.0) const
	This function returns a random float from lo inclusive to hi. More...

float	get_frand_pos (double lo=0.0, double hi=1.0) const
	This function returns a random float from lo to hi. More...

float	get_gauss_rand (float mean, float sigma) const
	Return a Gaussian random number. More...

void	print_generator_type () const
	print out all possible random number generator type in gsl More...

Static Public Member Functions
static Randnum *	Instance ()

static Randnum *	Instance (const gsl_rng_type *_t)

Protected Member Functions
	Randnum ()
	The default constructor will use the gsl default random number generator gal_rng_mt19937. More...

	Randnum (const Randnum &)

	Randnum (const gsl_rng_type *_t)
	This constructor is for setting the new random number generator engine other than gsl default gsl_rng_mt19937. More...

	~Randnum ()

Static Private Attributes
static const gsl_rng_type *	T = gsl_rng_default

static gsl_rng *	r = 0

static unsigned long long	_seed = random_seed()

static Randnum *	_instance = 0

Detailed Description

The wrapper class for gsl's random number generater.

This class is a singleton class. the default random number generator engine is gsl default: gsl_rng_mt19937, gsl_rng_mt19937 has a period 2^19937. the default seed is from /dev/random or milli second of current time.

 - How to get a random integer in range [lo, hi]

Randnum *r = Randnum::Instance();

int i = r->get_irand(lo, hi);

EMAN::Randnum::Instance

static Randnum * Instance()

Definition: randnum.cpp:104

EMAN::Randnum::Randnum

Randnum()

The default constructor will use the gsl default random number generator gal_rng_mt19937.

Definition: randnum.cpp:125

EMAN::Randnum::r

static gsl_rng * r

Definition: randnum.h:166

How to get a random float in range [0, 1)
Randnum *r = Randnum::Instance();

float f = r->get_frand();
How to get a random float in range (0, 1)
Randnum *r = Randnum::Instance();

float f = r->get_frand_pos();
How to get a random float in range [lo, hi)
Randnum *r = Randnum::Instance();

float f = r->get_frand(lo, hi);
How to get a random float in range (lo, hi)
Randnum *r = Randnum::Instance();

float f = r->get_frand_pos(lo, hi);
How to get a gaussian distribution float with given mean and sigma
Randnum *r = Randnum::Instance();

float f = r->get_gauss_rand(mean, sigma);
How to set a seed for the random number generator
Randnum *r = Randnum::Instance();

r->set_seed(12345);
How to set a random number generator other than use the default
Randnum *r = Randnum::Instance(gsl_rng_rand); //gsl version of rand()

Randnum *r = Randnum::Instance(gsl_rng_random128_libc5); //gsl version of Linux's random()

Definition at line 86 of file randnum.h.

Constructor & Destructor Documentation

◆ Randnum() [1/3]

Randnum::Randnum ( )

protected

The default constructor will use the gsl default random number generator gal_rng_mt19937.

This is a very good choice which has a period of 2^19937 and not sacrifice performance too much.

Definition at line 125 of file randnum.cpp.

{
        r = gsl_rng_alloc (T);  
        gsl_rng_set(r, _seed ); 
}

References _seed, r, and T.

Referenced by Instance().

◆ Randnum() [2/3]

EMAN::Randnum::Randnum ( const Randnum & )

protected

◆ Randnum() [3/3]

Randnum::Randnum ( const gsl_rng_type * _t )

explicitprotected

This constructor is for setting the new random number generator engine other than gsl default gsl_rng_mt19937.

For example: gsl_rng_rand is the gsl version of rand() function, which is 100% faster than the rand() function in C.

Parameters

_t	the random number generator type

Definition at line 131 of file randnum.cpp.

{
        r = gsl_rng_alloc (_t); 
        gsl_rng_set(r, _seed );
}

References _seed, and r.

◆ ~Randnum()

Randnum::~Randnum ( )

protected

Definition at line 137 of file randnum.cpp.

{
        gsl_rng_free (r);
}

References r.

Member Function Documentation

◆ get_frand()

float Randnum::get_frand	(	double	lo = `0.0`,
		double	hi = `1.0`
	)		const

This function returns a random float from lo inclusive to hi.

Parameters

lo	the low end of the random float
hi	the high end of the random float

Returns: the float in [lo, hi), default in [0,0,1.0)

Definition at line 158 of file randnum.cpp.

{
        return static_cast<float>(gsl_rng_uniform(r) * (hi -lo) + lo);
}

References r.

Referenced by EMAN::Util::get_frand(), EMAN::AddRandomNoiseProcessor::process_inplace(), and EMAN::TestImageNoiseUniformRand::process_inplace().

◆ get_frand_pos()

float Randnum::get_frand_pos	(	double	lo = `0.0`,
		double	hi = `1.0`
	)		const

This function returns a random float from lo to hi.

Parameters

lo	the low end of the random float
hi	the high end of the random float

Returns: the float in (lo, hi), default in (0,0,1.0)

Definition at line 163 of file randnum.cpp.

{
        return static_cast<float>(gsl_rng_uniform_pos(r) * (hi -lo) + lo);
}

References r.

Referenced by get_gauss_rand().

◆ get_gauss_rand()

float Randnum::get_gauss_rand	(	float	mean,
		float	sigma
	)		const

Return a Gaussian random number.

Parameters

[in]	mean	The gaussian mean
[in]	sigma	The gaussian sigma

Returns: the gaussian random number in float.

Definition at line 168 of file randnum.cpp.

{
        float x = 0.0f;
        float y = 0.0f;
        float r = 0.0f;
        bool valid = true;
        
        while (valid) {
                x = get_frand_pos(-1.0, 1.0);
                y = get_frand_pos(-1.0, 1.0);
                r = x * x + y * y;
                
                if (r <= 1.0 && r > 0) {
                        valid = false;
                }
        }
        
        float f = std::sqrt(-2.0f * std::log(r) / r);
        float result = x * f * sigma + mean;
        return result;
}

References get_frand_pos(), log(), r, sqrt(), x, and y.

Referenced by EMAN::Util::get_gauss_rand(), EMAN::AddNoiseProcessor::process_inplace(), EMAN::AddRandomNoiseProcessor::process_inplace(), and EMAN::TestImageNoiseGauss::process_inplace().

◆ get_irand()

long long Randnum::get_irand	(	long long	lo,
		long long	hi
	)		const

This function returns a random integer from lo to hi inclusive.

All integers in the range [lo,hi] are produced with equal probability.

Parameters

lo	the low end of the random integer
hi	the high end of the random integer

Returns: the long integer in [lo, hi]

Definition at line 153 of file randnum.cpp.

{
        return gsl_rng_uniform_int(r, hi-lo+1)+lo;
}

References r.

Referenced by EMAN::Util::get_irand().

◆ get_seed()

unsigned long long Randnum::get_seed ( )

Get the current random number seed.

Returns: current seed

Definition at line 148 of file randnum.cpp.

{
        return _seed;
}

References _seed.

Referenced by EMAN::Util::get_randnum_seed().

◆ Instance() [1/2]

Randnum * Randnum::Instance ( )

static

Definition at line 104 of file randnum.cpp.

                            {
        if(_instance == 0) {
                _instance = new Randnum();
        }
        
        return _instance; 
}

References _instance, and Randnum().

Referenced by EMAN::Util::get_frand(), EMAN::Util::get_gauss_rand(), EMAN::Util::get_irand(), EMAN::Util::get_randnum_seed(), EMAN::AddNoiseProcessor::process_inplace(), EMAN::AddRandomNoiseProcessor::process_inplace(), EMAN::TestImageNoiseUniformRand::process_inplace(), EMAN::TestImageNoiseGauss::process_inplace(), and EMAN::Util::set_randnum_seed().

◆ Instance() [2/2]

Randnum * Randnum::Instance ( const gsl_rng_type * _t )

static

Definition at line 112 of file randnum.cpp.

                                                   {
        if(_instance == 0) {
                _instance = new Randnum(_t);
        }
        else if(_t != _instance->T) {
                gsl_rng_free (_instance->r);
                _instance->r = gsl_rng_alloc (_t);
                gsl_rng_set(_instance->r, _seed );
        }
        
        return _instance;
}

References _instance, _seed, r, Randnum(), and T.

◆ print_generator_type()

void Randnum::print_generator_type ( ) const

print out all possible random number generator type in gsl

Definition at line 190 of file randnum.cpp.

{
        const gsl_rng_type **t, **t0;
          
        t0 = gsl_rng_types_setup ();
          
        printf ("Available generators:\n");
          
        for (t = t0; *t != 0; t++) {
                printf ("%s\n", (*t)->name);
        }       
}

◆ set_seed()

void Randnum::set_seed ( unsigned long long seed )

Set the seed for the random number generator.

If the generator is seeded with the same value of s on two different runs, the same stream of random numbers will be generated by successive calls to the routines below. If different values of s are supplied, then the generated streams of random numbers should be completely different. If the seed s is zero then the standard seed from the original implementation is used instead.

Parameters

seed	the seed for random number generator

Definition at line 142 of file randnum.cpp.

{
        _seed = seed;
        gsl_rng_set(r, _seed);
}

References _seed, and r.

Referenced by EMAN::AddNoiseProcessor::process_inplace(), EMAN::AddRandomNoiseProcessor::process_inplace(), EMAN::TestImageNoiseUniformRand::process_inplace(), EMAN::TestImageNoiseGauss::process_inplace(), and EMAN::Util::set_randnum_seed().

Member Data Documentation

◆ _instance

Randnum * Randnum::_instance = 0

staticprivate

Definition at line 169 of file randnum.h.

Referenced by Instance().

◆ _seed

unsigned long long Randnum::_seed = random_seed()

staticprivate

Definition at line 167 of file randnum.h.

Referenced by get_seed(), Instance(), Randnum(), and set_seed().

◆ r

gsl_rng * Randnum::r = 0

staticprivate

Definition at line 166 of file randnum.h.

Referenced by get_frand(), get_frand_pos(), get_gauss_rand(), get_irand(), Instance(), Randnum(), set_seed(), and ~Randnum().

◆ T

const gsl_rng_type * Randnum::T = gsl_rng_default

staticprivate

Definition at line 165 of file randnum.h.

Referenced by Instance(), and Randnum().

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

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Randnum() [1/3]

◆ Randnum() [2/3]

◆ Randnum() [3/3]

◆ ~Randnum()

Member Function Documentation

◆ get_frand()

◆ get_frand_pos()

◆ get_gauss_rand()

◆ get_irand()

◆ get_seed()

◆ Instance() [1/2]

◆ Instance() [2/2]

◆ print_generator_type()

◆ set_seed()

Member Data Documentation

◆ _instance

◆ _seed

◆ r

◆ T