The zeta distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically. More...

#include <random-variable-stream.h>

Inheritance diagram for ns3::ZetaRandomVariable:

Collaboration diagram for ns3::ZetaRandomVariable:

Public Member Functions
	ZetaRandomVariable ()
	Creates a zeta distribution RNG with the default value for alpha.
double	GetAlpha (void) const
	Returns the alpha value for the zeta distribution returned by this RNG stream.
uint32_t	GetInteger (uint32_t alpha)
	Returns a random unsigned integer from a zeta distribution with the specified alpha.
virtual uint32_t	GetInteger (void)
	Returns a random unsigned integer from a zeta distribution with the current alpha.
double	GetValue (double alpha)
	Returns a random double from a zeta distribution with the specified alpha.
virtual double	GetValue (void)
	Returns a random double from a zeta distribution with the current alpha.
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::ZetaRandomVariable.

Private Attributes
double	m_alpha
	The alpha value for the zeta distribution returned by this RNG stream.
double	m_b
	Just for calculus simplifications.

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 zeta distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically.

This class supports the creation of objects that return random numbers from a fixed zeta distribution. It also supports the generation of single random numbers from various zeta distributions.

The Zeta distribution is closely related to Zipf distribution when N goes to infinity.

Zeta distribution has one parameter, alpha, $\alpha > 1$ (real). Probability Mass Function is $f(k; \alpha) = k^{-\alpha}/\zeta(\alpha)$ where $\zeta(\alpha)$ is the Riemann zeta function ( $\sum_{n=1}^\infty n^{-\alpha} )$

Here is an example of how to use this class:

double alpha = 2.0;
Ptr<ZetaRandomVariable> x = CreateObject<ZetaRandomVariable> ();
x->SetAttribute ("Alpha", DoubleValue (alpha));
// The expected value for the mean of the values returned by a
// zetaly distributed random variable is equal to 
//
//                   zeta(alpha - 1)
//     E[value]  =  ---------------   for alpha > 2 ,
//                     zeta(alpha)
//                          
// where zeta(alpha) is the Riemann zeta function.
//                 
// There are no simple analytic forms for the Riemann zeta
// function, which is the reason the known mean of the values
// cannot be calculated in this example.
//               
double value = x->GetValue ();

Definition at line 2183 of file random-variable-stream.h.

Constructor & Destructor Documentation

ns3::ZetaRandomVariable::ZetaRandomVariable ( )

Creates a zeta distribution RNG with the default value for alpha.

Definition at line 1253 of file random-variable-stream.cc.

Member Function Documentation

double ns3::ZetaRandomVariable::GetAlpha ( void ) const

Returns the alpha value for the zeta distribution returned by this RNG stream.

Returns: The alpha value for the zeta distribution returned by this RNG stream.

Definition at line 1259 of file random-variable-stream.cc.

References m_alpha.

uint32_t ns3::ZetaRandomVariable::GetInteger ( uint32_t alpha )

Returns a random unsigned integer from a zeta distribution with the specified alpha.

Parameters

alpha Alpha value for the zeta distribution.

Returns: A random unsigned integer value.

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.

Definition at line 1299 of file random-variable-stream.cc.

References GetValue().

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uint32_t ns3::ZetaRandomVariable::GetInteger ( void )

virtual

Returns a random unsigned integer from a zeta distribution with the current alpha.

Returns: A random unsigned integer value.

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 1310 of file random-variable-stream.cc.

References GetValue(), and m_alpha.

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TypeId ns3::ZetaRandomVariable::GetTypeId ( void )

static

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

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

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

Attributes defined for this type:

Alpha: The alpha value for the zeta distribution returned by this RNG stream.
- Set with class: ns3::DoubleValue
- Underlying type: double -1.79769e+308:1.79769e+308
- Initial value: 3.14
- Flags: construct write read

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 1241 of file random-variable-stream.cc.

References m_alpha, and ns3::TypeId::SetParent().

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double ns3::ZetaRandomVariable::GetValue ( double alpha )

Returns a random double from a zeta distribution with the specified alpha.

Parameters

alpha Alpha value for the zeta distribution.

Returns: A floating point random value.

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.

Definition at line 1265 of file random-variable-stream.cc.

References ns3::RandomVariableStream::IsAntithetic(), m_alpha, m_b, ns3::RandomVariableStream::Peek(), ns3::RngStream::RandU01(), and test().

Referenced by RandomVariableStreamZetaTestCase::DoRun(), and RandomVariableStreamZetaAntitheticTestCase::DoRun().

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double ns3::ZetaRandomVariable::GetValue ( void )

virtual

Returns a random double from a zeta distribution with the current alpha.

Returns: A floating point random value.

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.

Note that we have to re-implement this method here because the method is overloaded above for the two-argument variant and the c++ name resolution rules don't work well with overloads split between parent and child classes.

Implements ns3::RandomVariableStream.

Definition at line 1305 of file random-variable-stream.cc.

References m_alpha.

Referenced by GetInteger().

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