Ocean::RandomGenerator Class Reference

This class implements a generator for random numbers. More...

#include <RandomGenerator.h>

Public Member Functions
	RandomGenerator ()
	Creates a new random generator and initializes the internal parameter with the random value of the standard random function.
	RandomGenerator (RandomGenerator &generator)
	Creates a new random generator and initializes the internal parameter by a random value provided by the locked random function of the given generator.
	RandomGenerator (RandomGenerator *optionalGenerator)
	Creates a new random generator and optional initializes the internal parameter by a random value provided by the locked random function of the given generator, if no generator is provided the standard random function will be used for initialization.
	RandomGenerator (RandomGenerator &&randomGenerator)
	Move constructor.
	RandomGenerator (const unsigned int seed)
	Creates a new random generator and initializes the internal parameter by the given value.
unsigned int	rand ()
	Returns the next random number.
unsigned int	lockedRand ()
	Returns the next random number.
unsigned int	seed () const
	Returns the current seed value of this object.
unsigned int	initialSeed () const
	Returns the initial seed value which was used to initialize this random generator.
RandomGenerator &	operator= (RandomGenerator &&randomGenerator)
	Move operator.

Static Public Member Functions
static constexpr unsigned int	randMax ()
	Returns the maximal random value of this generator.

Static Private Member Functions
static unsigned int	threadAndTimeBasedSeed ()
	Returns a seed value based on the current time, the thread id, and a random value from RandomI.

Private Attributes
unsigned int	initialSeed_ = (unsigned int)(-1)
	The seed value which was used to initialize this random generator.
unsigned int	seed_ = (unsigned int)(-1)
	Internal seed parameter used for random number generation, changes whenever a new random number is generated.
Lock	lock_
	Generator lock.

Detailed Description

This class implements a generator for random numbers.

A random generator object can be used to improve the performance of code (needing random numbers) which is applied on several CPU cores in parallel.
The default random number functions of the standard library are thread-safe but may apply expensive locks to synchronize the individual seed parameters of the individual threads.
Therefore, this class can be used to improve the code performance significantly in multi-threaded environments.
The following code example shows the correct application of this class for multi-core functions (which can be invoked e.g., by the Worker class):

void multiCoreFunction(RandomGenerator& randomGenerator, unsigned int* data, unsigned int firstObject, unsigned int numberObjects)
{
    /// create a local random generator object which uses the function's random generator to create a new seed value
    RandomGenerator localRandomGenerator(randomGenerator);
 
    for (unsigned int n = firstObject; n <= firstObject + numberObjects; ++n)
    {
        /// we create random values and use the local random generator (not the function's random generator)
        data[n] = RandomI::random(localRandomGenerator, 100u);
    }
}

See also

RandomI, Worker.

Constructor & Destructor Documentation

RandomGenerator() [1/5]

Ocean::RandomGenerator::RandomGenerator

(

)

Creates a new random generator and initializes the internal parameter with the random value of the standard random function.

Ensure that RandomI::initialize() has been called before using this constructor.

See also

RandomI::initialize().

RandomGenerator() [2/5]

Ocean::RandomGenerator::RandomGenerator ( RandomGenerator &  generator )

inlineexplicit

Creates a new random generator and initializes the internal parameter by a random value provided by the locked random function of the given generator.

Parameters

generator

Random number generator used for initialization, the generator's seed will be changed during the initialization

RandomGenerator() [3/5]

Ocean::RandomGenerator::RandomGenerator ( RandomGenerator *  optionalGenerator )

explicit

Creates a new random generator and optional initializes the internal parameter by a random value provided by the locked random function of the given generator, if no generator is provided the standard random function will be used for initialization.

Parameters

optionalGenerator

The random number generator used for initialization (the generator's seed will be changed during the initialization), nullptr to use the standard random function for initialization

RandomGenerator() [4/5]

Ocean::RandomGenerator::RandomGenerator ( RandomGenerator &&  randomGenerator )

inline

Move constructor.

Parameters

randomGenerator

The random generator object to be moved

RandomGenerator() [5/5]

Ocean::RandomGenerator::RandomGenerator ( const unsigned int  seed )

inlineexplicit

Creates a new random generator and initializes the internal parameter by the given value.

Parameters

seed	The seed initialization value, with range [0, infinity)

Member Function Documentation

initialSeed()

unsigned int Ocean::RandomGenerator::initialSeed ( ) const

inline

Returns the initial seed value which was used to initialize this random generator.

The initial seed value will not change during the lifetime of the generator.

Returns

The random generator's initial seed value

lockedRand()

unsigned int Ocean::RandomGenerator::lockedRand ( )

inline

Returns the next random number.

This function is thread safe.

Returns

Random number with range [0, 32767]

See also

rand().

operator=()

RandomGenerator & Ocean::RandomGenerator::operator=

(

RandomGenerator &&

randomGenerator

)

Move operator.

Parameters

randomGenerator

The random generator object to be moved

Returns

Reference to this object

rand()

unsigned int Ocean::RandomGenerator::rand ( )

inline

Returns the next random number.

Beware: This function is not thread safe.

Returns

Random number with range [0, 32767]

See also

lockedRand().

randMax()

constexpr unsigned int Ocean::RandomGenerator::randMax ( )

staticconstexpr

Returns the maximal random value of this generator.

Returns

Maximal random value of this generator

seed()

unsigned int Ocean::RandomGenerator::seed ( ) const

inline

Returns the current seed value of this object.

This seed value changes whenever a new random number is generated.

Returns

Current seed value

threadAndTimeBasedSeed()

static unsigned int Ocean::RandomGenerator::threadAndTimeBasedSeed ( )

staticprivate

Returns a seed value based on the current time, the thread id, and a random value from RandomI.

Returns

The combined seed value

Field Documentation

initialSeed_

unsigned int Ocean::RandomGenerator::initialSeed_ = (unsigned int)(-1)

private

The seed value which was used to initialize this random generator.

lock_

Lock Ocean::RandomGenerator::lock_

private

Generator lock.

seed_

unsigned int Ocean::RandomGenerator::seed_ = (unsigned int)(-1)

private

Internal seed parameter used for random number generation, changes whenever a new random number is generated.

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

• RandomGenerator.h