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ns3::ZetaRandomVariable Class Reference

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 () const
 Returns the alpha value for the zeta distribution returned by this RNG stream.
 
virtual uint32_t GetInteger ()
 Get the next random value drawn from the distribution.
 
uint32_t GetInteger (uint32_t alpha)
 Get the next random value drawn from the distribution.
 
double GetValue () override
 Get the next random value drawn from the distribution.
 
double GetValue (double alpha)
 Get the next random value drawn from the distribution.
 
- 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.
 
RandomVariableStreamoperator= (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< ObjectGetObject () 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< ObjectGetObject (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.
 
SimpleRefCountoperator= (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 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_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
RngStreamPeek () 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.
 

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 related to Zipf distribution by letting $N \rightarrow \infty$.

Zeta distribution has one parameter, Alpha, $ \alpha > 1 $ (real). (Note the Wikipedia entry for the Zeta Distribution uses the symbol $s$ instead of $\alpha$.) The probability mass Function is

\[
     P(k; \alpha) = k^{-\alpha}/\zeta(\alpha)
  \]

where $ \zeta(\alpha) $ is the Riemann zeta function

\[
    \zeta(\alpha) = \sum_{n=1}^\infty \frac{1}{n^\alpha}
  \]

Note the Zeta distribution is a discrete distribution, so the returned values $k$ will always be integers in the range $k \in {1,2 \dots} $.

The mean value of the distribution is

\[
      \mu = \frac{\zeta(\alpha - 1)}{\zeta(\alpha)}, \quad \alpha > 2
   \]

The Zeta RNG $x$ is generated by an accept-reject algorithm; see the implementation of GetValue(double).

Example

Here is an example of how to use this class:

double alpha = 2.0;
x->SetAttribute ("Alpha", DoubleValue (alpha));
double value = x->GetValue ();
This class can be used to hold variables of floating point type such as 'double' or 'float'.
Definition double.h:31
Smart pointer class similar to boost::intrusive_ptr.
Ptr< T > CreateObject(Args &&... args)
Create an object by type, with varying number of constructor parameters.
Definition object.h:619
Antithetic Values.

If an instance of this RNG is configured to return antithetic values, the actual value returned, $x'$, is generated by using $ 1 - u $ instead. of $u$ on [0, 1].

Definition at line 1757 of file random-variable-stream.h.

Constructor & Destructor Documentation

◆ ZetaRandomVariable()

ns3::ZetaRandomVariable::ZetaRandomVariable ( )

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

Definition at line 1401 of file random-variable-stream.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

◆ GetAlpha()

double ns3::ZetaRandomVariable::GetAlpha ( ) 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 1408 of file random-variable-stream.cc.

References m_alpha.

◆ GetInteger() [1/2]

uint32_t ns3::RandomVariableStream::GetInteger ( )
virtual

Get the next random value drawn from the distribution.

Returns
A random value.

Reimplemented from ns3::RandomVariableStream.

Definition at line 144 of file random-variable-stream.cc.

◆ GetInteger() [2/2]

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

Get the next random value drawn from the distribution.

Returns
A random value.
Parameters
[in]alphaAlpha value for the zeta distribution.

Definition at line 1449 of file random-variable-stream.cc.

References ns3::RandomVariableStream::GetStream(), GetValue(), and NS_LOG_DEBUG.

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◆ GetTypeId()

TypeId ns3::ZetaRandomVariable::GetTypeId ( )
static

Register this type.

Returns
The object TypeId.

Definition at line 1386 of file random-variable-stream.cc.

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

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◆ GetValue() [1/2]

double ns3::ZetaRandomVariable::GetValue ( )
overridevirtual

Get the next random value drawn from the distribution.

Returns
A random value.

Implements ns3::RandomVariableStream.

Definition at line 1457 of file random-variable-stream.cc.

References GetValue(), and m_alpha.

Referenced by GetInteger(), and GetValue().

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◆ GetValue() [2/2]

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

Get the next random value drawn from the distribution.

Returns
A random value.
Parameters
[in]alphaAlpha value for the zeta distribution.

Definition at line 1414 of file random-variable-stream.cc.

References ns3::RandomVariableStream::GetStream(), ns3::RandomVariableStream::IsAntithetic(), m_b, NS_LOG_DEBUG, ns3::RandomVariableStream::Peek(), and ns3::RngStream::RandU01().

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Member Data Documentation

◆ m_alpha

double ns3::ZetaRandomVariable::m_alpha
private

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

Definition at line 1793 of file random-variable-stream.h.

Referenced by GetAlpha(), GetTypeId(), and GetValue().

◆ m_b

double ns3::ZetaRandomVariable::m_b
private

Just for calculus simplifications.

Definition at line 1796 of file random-variable-stream.h.

Referenced by GetValue().


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