The Random Number Generator (RNG) that has a specified empirical distribution. More...

#include <random-variable-stream.h>

Inheritance diagram for ns3::EmpiricalRandomVariable:

Collaboration diagram for ns3::EmpiricalRandomVariable:

Classes
class	ValueCDF

Public Member Functions
	EmpiricalRandomVariable ()
	Creates an empirical RNG that has a specified, empirical distribution.
void	CDF (double v, double c)
	Specifies a point in the empirical distribution.
virtual uint32_t	GetInteger (void)
	Returns the next value in the empirical distribution.
virtual double	GetValue (void)
	Returns the next value in the empirical distribution.
Public Member Functions inherited from ns3::RandomVariableStream
	RandomVariableStream ()
virtual	~RandomVariableStream ()
int64_t	GetStream (void) const
	Returns the stream number for this RNG stream.
bool	IsAntithetic (void) const
	Returns true if antithetic values should be generated.
void	SetAntithetic (bool isAntithetic)
	Specifies whether antithetic values should be generated.
void	SetStream (int64_t stream)
	Specifies the stream number for this RNG stream.
Public Member Functions inherited from ns3::Object
	Object ()
virtual	~Object ()
void	AggregateObject (Ptr< Object > other)
void	Dispose (void)
AggregateIterator	GetAggregateIterator (void) const
virtual TypeId	GetInstanceTypeId (void) const
template<typename T >
Ptr< T >	GetObject (void) const
template<typename T >
Ptr< T >	GetObject (TypeId tid) const
void	Start (void)
Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
	SimpleRefCount ()
	SimpleRefCount (const SimpleRefCount &o)
uint32_t	GetReferenceCount (void) const
SimpleRefCount &	operator= (const SimpleRefCount &o)
void	Ref (void) const
void	Unref (void) const
Public Member Functions inherited from ns3::ObjectBase
virtual	~ObjectBase ()
void	GetAttribute (std::string name, AttributeValue &value) const
bool	GetAttributeFailSafe (std::string name, AttributeValue &attribute) const
void	SetAttribute (std::string name, const AttributeValue &value)
bool	SetAttributeFailSafe (std::string name, const AttributeValue &value)
bool	TraceConnect (std::string name, std::string context, const CallbackBase &cb)
bool	TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
bool	TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
bool	TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)

Static Public Member Functions
static TypeId	GetTypeId (void)
	This method returns the TypeId associated to ns3::EmpiricalRandomVariable.

Private Member Functions
virtual double	Interpolate (double, double, double, double, double)
virtual void	Validate ()

Private Attributes
std::vector< ValueCDF >	emp
bool	validated

Additional Inherited Members
Protected Member Functions inherited from ns3::RandomVariableStream
RngStream *	Peek (void) const
	Returns a pointer to the underlying RNG stream.

Detailed Description

The Random Number Generator (RNG) that has a specified empirical distribution.

Defines a random variable that has a specified, empirical distribution. The distribution is specified by a series of calls to the CDF member function, specifying a value and the probability that the function value is less than the specified value. When values are requested, a uniform random variable is used to select a probability, and the return value is interpreted linearly between the two appropriate points in the CDF. The method is known as inverse transform sampling: (http://en.wikipedia.org/wiki/Inverse_transform_sampling).

Here is an example of how to use this class:

// Create the RNG with a uniform distribution between 0 and 10.
Ptr<EmpiricalRandomVariable> x = CreateObject<EmpiricalRandomVariable> ();
x->CDF ( 0.0,  0.0);
x->CDF ( 5.0,  0.5);
x->CDF (10.0,  1.0);
// The expected value for the mean of the values returned by this
// empirical distribution is the midpoint of the distribution
//
//     E[value]  =  5 .
//                          
double value = x->GetValue ();

Definition at line 2373 of file random-variable-stream.h.

Constructor & Destructor Documentation

ns3::EmpiricalRandomVariable::EmpiricalRandomVariable ( )

Creates an empirical RNG that has a specified, empirical distribution.

Definition at line 1410 of file random-variable-stream.cc.

Member Function Documentation

void ns3::EmpiricalRandomVariable::CDF	(	double	v,
		double	c
	)

Specifies a point in the empirical distribution.

Parameters

v	The function value for this point
c	Probability that the function is less than or equal to v

Definition at line 1475 of file random-variable-stream.cc.

References emp.

Referenced by RandomVariableStreamEmpiricalTestCase::DoRun(), RandomVariableStreamEmpiricalAntitheticTestCase::DoRun(), and main().

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uint32_t ns3::EmpiricalRandomVariable::GetInteger ( void )

virtual

Returns the next value in the empirical distribution.

Returns: The integer next value in the empirical distribution.

Note that antithetic values are being generated if m_isAntithetic is equal to true. If $u$ is a uniform variable over [0,1] and $x$ is a value that would be returned normally, then $(1 - u$ ) is the distance that $u$ would be from $1$ . The value returned in the antithetic case, $x'$ , uses (1-u), which is the distance $u$ is from the 1.

Implements ns3::RandomVariableStream.

Definition at line 1470 of file random-variable-stream.cc.

References GetValue().

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TypeId ns3::EmpiricalRandomVariable::GetTypeId ( void )

static

This method returns the TypeId associated to ns3::EmpiricalRandomVariable.

This object is accessible through the following paths with Config::Set and Config::Connect:

/NodeList/[i]/$ns3::MobilityModel/$ns3::GaussMarkovMobilityModel/MeanDirection/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::GaussMarkovMobilityModel/MeanPitch/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::GaussMarkovMobilityModel/MeanVelocity/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomDirection2dMobilityModel/Pause/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomDirection2dMobilityModel/Speed/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWalk2dMobilityModel/Direction/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWalk2dMobilityModel/Speed/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/Pause/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomBoxPositionAllocator/X/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomBoxPositionAllocator/Y/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomBoxPositionAllocator/Z/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomDiscPositionAllocator/Rho/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomDiscPositionAllocator/Theta/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomRectanglePositionAllocator/X/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomRectanglePositionAllocator/Y/$ns3::EmpiricalRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/Speed/$ns3::EmpiricalRandomVariable
/NodeList/[i]/ApplicationList/[i]/$ns3::OnOffApplication/OffTime/$ns3::EmpiricalRandomVariable
/NodeList/[i]/ApplicationList/[i]/$ns3::OnOffApplication/OnTime/$ns3::EmpiricalRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::CsmaNetDevice/ReceiveErrorModel/$ns3::RateErrorModel/RanVar/$ns3::EmpiricalRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::PointToPointNetDevice/ReceiveErrorModel/$ns3::RateErrorModel/RanVar/$ns3::EmpiricalRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::SimpleNetDevice/ReceiveErrorModel/$ns3::RateErrorModel/RanVar/$ns3::EmpiricalRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::WifiNetDevice/Channel/$ns3::YansWifiChannel/PropagationDelayModel/$ns3::RandomPropagationDelayModel/Variable/$ns3::EmpiricalRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::WifiNetDevice/Channel/$ns3::YansWifiChannel/PropagationLossModel/$ns3::RandomPropagationLossModel/Variable/$ns3::EmpiricalRandomVariable

No Attributes defined for this type.
Attributes defined in parent class ns3::RandomVariableStream:

Stream: The stream number for this RNG stream. -1 means "allocate a stream automatically". Note that if -1 is set, Get will return -1 so that it is not possible to know which value was automatically allocated.
- Set with class: ns3::IntegerValue
- Underlying type: int64_t -9223372036854775808:9223372036854775807
- Initial value: -1
- Flags: construct write read
Antithetic: Set this RNG stream to generate antithetic values
- Set with class: BooleanValue
- Underlying type: bool
- Initial value: false
- Flags: construct write read

No TraceSources defined for this type.

Reimplemented from ns3::RandomVariableStream.

Definition at line 1402 of file random-variable-stream.cc.

References ns3::TypeId::SetParent().

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double ns3::EmpiricalRandomVariable::GetValue ( void )

virtual

Returns the next value in the empirical distribution.

Returns: The floating point next value in the empirical distribution.

Note that antithetic values are being generated if m_isAntithetic is equal to true. If $u$ is a uniform variable over [0,1] and $x$ is a value that would be returned normally, then $(1 - u$ ) is the distance that $u$ would be from $1$ . The value returned in the antithetic case, $x'$ , uses (1-u), which is the distance $u$ is from the 1.

Implements ns3::RandomVariableStream.

Definition at line 1417 of file random-variable-stream.cc.

References emp, Interpolate(), ns3::RandomVariableStream::IsAntithetic(), ns3::RandomVariableStream::Peek(), ns3::RngStream::RandU01(), Validate(), and validated.

Referenced by RandomVariableStreamEmpiricalTestCase::DoRun(), RandomVariableStreamEmpiricalAntitheticTestCase::DoRun(), and GetInteger().

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