The laplacian distribution Random Number Generator (RNG). More...

#include "random-variable-stream.h"

Inheritance diagram for ns3::LaplacianRandomVariable:

Collaboration diagram for ns3::LaplacianRandomVariable:

Public Member Functions
	LaplacianRandomVariable ()
	Creates an unbounded laplacian distribution RNG with the default values for the location and the scale.

double	GetBound () const
	Get the configured bound of this RNG.

virtual uint32_t	GetInteger ()
	Get the next random value drawn from the distribution.

uint32_t	GetInteger (uint32_t location, uint32_t scale, uint32_t bound)
	Get the next random value drawn from the distribution.

double	GetLocation () const
	Get the configured location value of this RNG.

double	GetScale () const
	Get the configured scale value of this RNG.

double	GetValue () override
	Get the next random value drawn from the distribution.

double	GetValue (double location, double scale, double bound)
	Get the next random value drawn from the distribution.

double	GetVariance () const
	Returns the variance value for the laplacian distribution returned by this RNG stream.

Public Member Functions inherited from ns3::RandomVariableStream
	RandomVariableStream ()
	Default constructor.

	RandomVariableStream (const RandomVariableStream &)=delete

	~RandomVariableStream () override
	Destructor.

int64_t	GetStream () const
	Returns the stream number for the RngStream.

bool	IsAntithetic () const
	Check if antithetic values will be generated.

RandomVariableStream &	operator= (const RandomVariableStream &)=delete

void	SetAntithetic (bool isAntithetic)
	Specify whether antithetic values should be generated.

void	SetStream (int64_t stream)
	Specifies the stream number for the RngStream.

Public Member Functions inherited from ns3::Object
	Object ()
	Constructor.

	~Object () override
	Destructor.

void	AggregateObject (Ptr< Object > other)
	Aggregate two Objects together.

void	Dispose ()
	Dispose of this Object.

AggregateIterator	GetAggregateIterator () const
	Get an iterator to the Objects aggregated to this one.

TypeId	GetInstanceTypeId () const override
	Get the most derived TypeId for this Object.

template<typename T >
Ptr< T >	GetObject () const
	Get a pointer to the requested aggregated Object.

template<>
Ptr< Object >	GetObject () const
	Specialization of () for objects of type ns3::Object.

template<typename T >
Ptr< T >	GetObject (TypeId tid) const
	Get a pointer to the requested aggregated Object by TypeId.

template<>
Ptr< Object >	GetObject (TypeId tid) const
	Specialization of (TypeId tid) for objects of type ns3::Object.

void	Initialize ()
	Invoke DoInitialize on all Objects aggregated to this one.

bool	IsInitialized () const
	Check if the object has been initialized.

void	UnidirectionalAggregateObject (Ptr< Object > other)
	Aggregate an Object to another Object.

Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
	SimpleRefCount ()
	Default constructor.

	SimpleRefCount (const SimpleRefCount &o)
	Copy constructor.

uint32_t	GetReferenceCount () const
	Get the reference count of the object.

SimpleRefCount &	operator= (const SimpleRefCount &o)
	Assignment operator.

void	Ref () const
	Increment the reference count.

void	Unref () const
	Decrement the reference count.

Public Member Functions inherited from ns3::ObjectBase
virtual	~ObjectBase ()
	Virtual destructor.

void	GetAttribute (std::string name, AttributeValue &value, bool permissive=false) const
	Get the value of an attribute, raising fatal errors if unsuccessful.

bool	GetAttributeFailSafe (std::string name, AttributeValue &value) const
	Get the value of an attribute without raising errors.

void	SetAttribute (std::string name, const AttributeValue &value)
	Set a single attribute, raising fatal errors if unsuccessful.

bool	SetAttributeFailSafe (std::string name, const AttributeValue &value)
	Set a single attribute without raising errors.

bool	TraceConnect (std::string name, std::string context, const CallbackBase &cb)
	Connect a TraceSource to a Callback with a context.

bool	TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
	Connect a TraceSource to a Callback without a context.

bool	TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected with a context.

bool	TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected without a context.

Static Public Member Functions
static TypeId	GetTypeId ()
	Register this type.

static double	GetVariance (double scale)
	Returns the variance value for the laplacian distribution returned by this RNG stream.

Static Public Member Functions inherited from ns3::RandomVariableStream
static TypeId	GetTypeId ()
	Register this type.

Static Public Member Functions inherited from ns3::Object
static TypeId	GetTypeId ()
	Register this type.

Static Public Member Functions inherited from ns3::ObjectBase
static TypeId	GetTypeId ()
	Get the type ID.

Private Attributes
double	m_bound
	The bound on values that can be returned by this RNG stream.

double	m_location
	The location value of the laplacian distribution.

double	m_scale
	The scale value of the laplacian distribution.

Additional Inherited Members
Protected Member Functions inherited from ns3::RandomVariableStream
RngStream *	Peek () const
	Get the pointer to the underlying RngStream.

Protected Member Functions inherited from ns3::Object
	Object (const Object &o)
	Copy an Object.

virtual void	DoDispose ()
	Destructor implementation.

virtual void	DoInitialize ()
	Initialize() implementation.

virtual void	NotifyNewAggregate ()
	Notify all Objects aggregated to this one of a new Object being aggregated.

Protected Member Functions inherited from ns3::ObjectBase
void	ConstructSelf (const AttributeConstructionList &attributes)
	Complete construction of ObjectBase; invoked by derived classes.

virtual void	NotifyConstructionCompleted ()
	Notifier called once the ObjectBase is fully constructed.

Related Symbols inherited from ns3::ObjectBase
static TypeId	GetObjectIid ()
	Ensure the TypeId for ObjectBase gets fully configured to anchor the inheritance tree properly.

Detailed Description

The laplacian distribution Random Number Generator (RNG).

This class supports the creation of objects that return random numbers from a fixed laplacian distribution.

The probability density function of a laplacian variable is defined as:

$P(x; \mu, \beta) dx = \frac{1}{2 \beta} e^{\frac{- \abs{x - \mu}}{\beta}} dx$

where $\mu$ is the Location configurable attribute and $\beta$ is the Scale configurable attribute. This distribution has mean $\mu$ and variance $\sigma^2 = 2 \beta^2$ .

The laplacian RNG value is generated by

$x = \mu - \beta sgn(u) \log(1 - 2 \abs{u})$

where is a uniform random variable on [-0.5,0.5).

Bounded Distribution

The Laplacian distribution can be bounded symmetrically about the mean by the Bound parameter, , i.e. its values are confined to the interval $[\mu - b, \mu + b]$ . This preserves the mean but decreases the variance.