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ns3::WeibullRandomVariable Class Reference

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

#include "random-variable-stream.h"

Inheritance diagram for ns3::WeibullRandomVariable:
Collaboration diagram for ns3::WeibullRandomVariable:

## Public Member Functions

WeibullRandomVariable ()
Creates a Weibull distribution RNG with the default values for the scale, shape, and upper bound. More...

double GetBound (void) const
Returns the upper bound on values that can be returned by this RNG stream. More...

uint32_t GetInteger (uint32_t scale, uint32_t shape, uint32_t bound)
Returns a random unsigned integer from a Weibull distribution with the specified scale, shape, and upper bound. More...

virtual uint32_t GetInteger (void)
Returns a random unsigned integer from a Weibull distribution with the current scale, shape, and upper bound. More...

double GetScale (void) const
Returns the scale parameter for the Weibull distribution returned by this RNG stream. More...

double GetShape (void) const
Returns the shape parameter for the Weibull distribution returned by this RNG stream. More...

double GetValue (double scale, double shape, double bound)
Returns a random double from a Weibull distribution with the specified scale, shape, and upper bound. More...

virtual double GetValue (void)
Returns a random double from a Weibull distribution with the current scale, shape, and upper bound. More...

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

virtual ~RandomVariableStream ()
Destructor. More...

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

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

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

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

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

virtual ~Object ()
Destructor. More...

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

void Dispose (void)
Dispose of this Object. More...

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

virtual TypeId GetInstanceTypeId (void) const
Get the most derived TypeId for this Object. More...

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

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

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

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

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

SimpleRefCount (const SimpleRefCount &o)
Copy constructor. More...

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

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

void Ref (void) const
Increment the reference count. More...

void Unref (void) const
Decrement the reference count. More...

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

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

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

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

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

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

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

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

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

## Static Public Member Functions

static TypeId GetTypeId (void)
Register this type. More...

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

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

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

## Private Attributes

double m_bound
The upper bound on values that can be returned by this RNG stream. More...

double m_scale
The scale parameter for the Weibull distribution returned by this RNG stream. More...

double m_shape
The shape parameter for the Weibull distribution returned by this RNG stream. More...

Protected Member Functions inherited from ns3::RandomVariableStream
RngStreamPeek (void) const
Get the pointer to the underlying RngStream. More...

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

virtual void DoDispose (void)
Destructor implementation. More...

virtual void DoInitialize (void)
Initialize() implementation. More...

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

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

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

## Detailed Description

The Weibull 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 Weibull distribution. It also supports the generation of single random numbers from various Weibull distributions.

The probability density function is defined over the interval [0, $$+\infty$$] as: $$\frac{k}{\lambda}\left(\frac{x}{\lambda}\right)^{k-1}e^{-\left(\frac{x}{\lambda}\right)^k}$$ where $$k > 0$$ is the shape parameter and $$\lambda > 0$$ is the scale parameter. The specified mean is related to the scale and shape parameters by the following relation: $$mean = \lambda\Gamma\left(1+\frac{1}{k}\right)$$ where $$\Gamma$$ is the Gamma function.

Since Weibull distributions can theoretically return unbounded values, it is sometimes useful to specify a fixed upper limit. Note however when the upper limit is specified, the true mean of the distribution is slightly smaller than the mean value specified.

Here is an example of how to use this class:

double scale = 5.0;
double shape = 1.0;
Ptr<WeibullRandomVariable> x = CreateObject<WeibullRandomVariable> ();
x->SetAttribute ("Scale", DoubleValue (scale));
x->SetAttribute ("Shape", DoubleValue (shape));
// The expected value for the mean of the values returned by a
// Weibull distributed random variable is
//
// E[value] = scale * Gamma(1 + 1 / shape) ,
//
// where Gamma() is the Gamma function. Note that
//
// Gamma(n) = (n - 1)!
//
// if n is a positive integer.
//
// For this example,
//
// Gamma(1 + 1 / shape) = Gamma(1 + 1 / 1)
// = Gamma(2)
// = (2 - 1)!
// = 1
//
// which means
//
// E[value] = scale .
//
double value = x->GetValue ();

### Config Paths

ns3::WeibullRandomVariable is accessible through the following paths with Config::Set and Config::Connect:

• "/NodeList/[i]/DeviceList/[i]/$ns3::SimpleNetDevice/ReceiveErrorModel/$ns3::RateErrorModel/RanVar/$ns3::WeibullRandomVariable" • "/NodeList/[i]/DeviceList/[i]/$ns3::SimpleNetDevice/ReceiveErrorModel/$ns3::BurstErrorModel/BurstStart/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/DeviceList/[i]/$ns3::SimpleNetDevice/ReceiveErrorModel/$ns3::BurstErrorModel/BurstSize/$ns3::WeibullRandomVariable" • "/NodeList/[i]/DeviceList/[i]/$ns3::CsmaNetDevice/ReceiveErrorModel/$ns3::RateErrorModel/RanVar/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/DeviceList/[i]/$ns3::CsmaNetDevice/ReceiveErrorModel/$ns3::BurstErrorModel/BurstStart/$ns3::WeibullRandomVariable" • "/NodeList/[i]/DeviceList/[i]/$ns3::CsmaNetDevice/ReceiveErrorModel/$ns3::BurstErrorModel/BurstSize/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/DeviceList/[i]/$ns3::PointToPointNetDevice/ReceiveErrorModel/$ns3::RateErrorModel/RanVar/$ns3::WeibullRandomVariable" • "/NodeList/[i]/DeviceList/[i]/$ns3::PointToPointNetDevice/ReceiveErrorModel/$ns3::BurstErrorModel/BurstStart/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/DeviceList/[i]/$ns3::PointToPointNetDevice/ReceiveErrorModel/$ns3::BurstErrorModel/BurstSize/$ns3::WeibullRandomVariable" • "/NodeList/[i]/DeviceList/[i]/$ns3::WifiNetDevice/Channel/$ns3::YansWifiChannel/PropagationLossModel/$ns3::RandomPropagationLossModel/Variable/$ns3::WeibullRandomVariable" • "/NodeList/[i]/DeviceList/[i]/$ns3::WifiNetDevice/Channel/$ns3::YansWifiChannel/PropagationDelayModel/$ns3::RandomPropagationDelayModel/Variable/$ns3::WeibullRandomVariable" • "/NodeList/[i]/DeviceList/[i]/$ns3::WaveNetDevice/Channel/$ns3::YansWifiChannel/PropagationLossModel/$ns3::RandomPropagationLossModel/Variable/$ns3::WeibullRandomVariable" • "/NodeList/[i]/DeviceList/[i]/$ns3::WaveNetDevice/Channel/$ns3::YansWifiChannel/PropagationDelayModel/$ns3::RandomPropagationDelayModel/Variable/$ns3::WeibullRandomVariable" • "/NodeList/[i]/ApplicationList/[i]/$ns3::DhcpClient/Transactions/$ns3::WeibullRandomVariable" • "/NodeList/[i]/ApplicationList/[i]/$ns3::OnOffApplication/OnTime/$ns3::WeibullRandomVariable" • "/NodeList/[i]/ApplicationList/[i]/$ns3::OnOffApplication/OffTime/$ns3::WeibullRandomVariable" • "/NodeList/[i]/$ns3::MobilityModel/$ns3::GaussMarkovMobilityModel/MeanVelocity/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::GaussMarkovMobilityModel/MeanDirection/$ns3::WeibullRandomVariable" • "/NodeList/[i]/$ns3::MobilityModel/$ns3::GaussMarkovMobilityModel/MeanPitch/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomDirection2dMobilityModel/Speed/$ns3::WeibullRandomVariable" • "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomDirection2dMobilityModel/Pause/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWalk2dMobilityModel/Direction/$ns3::WeibullRandomVariable" • "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWalk2dMobilityModel/Speed/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/Speed/$ns3::WeibullRandomVariable" • "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/Pause/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomRectanglePositionAllocator/X/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomRectanglePositionAllocator/Y/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomBoxPositionAllocator/X/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomBoxPositionAllocator/Y/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomBoxPositionAllocator/Z/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomDiscPositionAllocator/Theta/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomDiscPositionAllocator/Rho/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::OutdoorPositionAllocator/X/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::OutdoorPositionAllocator/Y/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::OutdoorPositionAllocator/Z/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::ArpL3Protocol/RequestJitter/$ns3::WeibullRandomVariable"
• "/NodeList/[i]/$ns3::Icmpv6L4Protocol/SolicitationJitter/$ns3::WeibullRandomVariable"
• "/ChannelList/[i]/$ns3::YansWifiChannel/PropagationLossModel/$ns3::RandomPropagationLossModel/Variable/$ns3::WeibullRandomVariable" • "/ChannelList/[i]/$ns3::YansWifiChannel/PropagationDelayModel/$ns3::RandomPropagationDelayModel/Variable/$ns3::WeibullRandomVariable"

### Attributes

• Scale: The scale parameter for the Weibull distribution returned by this RNG stream.
• Set with class: ns3::DoubleValue
• Underlying type: double -1.79769e+308:1.79769e+308
• Initial value: 1
• Shape: The shape parameter for the Weibull distribution returned by this RNG stream.
• Set with class: ns3::DoubleValue
• Underlying type: double -1.79769e+308:1.79769e+308
• Initial value: 1
• Bound: The upper bound on the values returned by this RNG stream.
• Set with class: ns3::DoubleValue
• Underlying type: double -1.79769e+308:1.79769e+308
• Initial value: 0

### 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
• Antithetic: Set this RNG stream to generate antithetic values
• Set with class: BooleanValue
• Underlying type: bool
• Initial value: false

No TraceSources are defined for this type.
Size of this type is 80 bytes (on a 64-bit architecture).

Definition at line 864 of file random-variable-stream.h.

## Constructor & Destructor Documentation

 ns3::WeibullRandomVariable::WeibullRandomVariable ( )

Creates a Weibull distribution RNG with the default values for the scale, shape, and upper bound.

Definition at line 592 of file random-variable-stream.cc.

References NS_LOG_FUNCTION.

## Member Function Documentation

 double ns3::WeibullRandomVariable::GetBound ( void ) const

Returns the upper bound on values that can be returned by this RNG stream.

Returns
The upper bound on values that can be returned by this RNG stream.

Definition at line 612 of file random-variable-stream.cc.

References NS_LOG_FUNCTION.

 uint32_t ns3::WeibullRandomVariable::GetInteger ( uint32_t scale, uint32_t shape, uint32_t bound )

Returns a random unsigned integer from a Weibull distribution with the specified scale, shape, and upper bound.

Parameters
 [in] scale Scale parameter for the Weibull distribution. [in] shape Shape parameter for the Weibull distribution. [in] bound Upper bound on values returned.
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

$x = scale * {(-\log(u))}^{\frac{1}{shape}}$

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, $$x'$$, is calculated as

$x' = scale * {(-\log(1 - u))}^{\frac{1}{shape}} ,$

which now involves the log of the distance $$u$$ is from 1.

Definition at line 643 of file random-variable-stream.cc.

References ns3::SequentialRandomVariable::GetValue(), and NS_LOG_FUNCTION.

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 uint32_t ns3::WeibullRandomVariable::GetInteger ( void )
virtual

Returns a random unsigned integer from a Weibull distribution with the current scale, shape, and upper bound.

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

$x = scale * {(-\log(u))}^{\frac{1}{shape}}$

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, $$x'$$, is calculated as

$x' = scale * {(-\log(1 - u))}^{\frac{1}{shape}} ,$

which now involves the log of the distance $$u$$ is from 1.

Implements ns3::RandomVariableStream.

Definition at line 656 of file random-variable-stream.cc.

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 double ns3::WeibullRandomVariable::GetScale ( void ) const

Returns the scale parameter for the Weibull distribution returned by this RNG stream.

Returns
The scale parameter for the Weibull distribution returned by this RNG stream.

Definition at line 600 of file random-variable-stream.cc.

References NS_LOG_FUNCTION.

 double ns3::WeibullRandomVariable::GetShape ( void ) const

Returns the shape parameter for the Weibull distribution returned by this RNG stream.

Returns
The shape parameter for the Weibull distribution returned by this RNG stream.

Definition at line 606 of file random-variable-stream.cc.

References NS_LOG_FUNCTION.

 TypeId ns3::WeibullRandomVariable::GetTypeId ( void )
static

Register this type.

Returns
The object TypeId.

Definition at line 571 of file random-variable-stream.cc.

References m_bound, m_scale, m_shape, ns3::MakeDoubleAccessor(), and ns3::TypeId::SetParent().

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 double ns3::WeibullRandomVariable::GetValue ( double scale, double shape, double bound )

Returns a random double from a Weibull distribution with the specified scale, shape, and upper bound.

Parameters
 [in] scale Scale parameter for the Weibull distribution. [in] shape Shape parameter for the Weibull distribution. [in] bound Upper bound on values returned.
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

$x = scale * {(-\log(u))}^{\frac{1}{shape}}$

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, $$x'$$, is calculated as

$x' = scale * {(-\log(1 - u))}^{\frac{1}{shape}} ,$

which now involves the log of the distance $$u$$ is from 1.

Definition at line 619 of file random-variable-stream.cc.

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 double ns3::WeibullRandomVariable::GetValue ( void )
virtual

Returns a random double from a Weibull distribution with the current scale, shape, and upper bound.

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

$x = scale * {(-\log(u))}^{\frac{1}{shape}}$

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, $$x'$$, is calculated as

$x' = scale * {(-\log(1 - u))}^{\frac{1}{shape}} ,$

which now involves the log of the distance $$u$$ is from 1.

Note that we have to re-implement this method here because the method is overloaded above for the three-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 650 of file random-variable-stream.cc.

References ns3::SequentialRandomVariable::GetValue(), and NS_LOG_FUNCTION.

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## Member Data Documentation

 double ns3::WeibullRandomVariable::m_bound
private

The upper bound on values that can be returned by this RNG stream.

Definition at line 1012 of file random-variable-stream.h.

Referenced by GetTypeId().

 double ns3::WeibullRandomVariable::m_scale
private

The scale parameter for the Weibull distribution returned by this RNG stream.

Definition at line 1006 of file random-variable-stream.h.

Referenced by GetTypeId().

 double ns3::WeibullRandomVariable::m_shape
private

The shape parameter for the Weibull distribution returned by this RNG stream.

Definition at line 1009 of file random-variable-stream.h.

Referenced by GetTypeId().

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