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ns3::UniformRandomVariable Class Reference
Core » Random Variables

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

#include "random-variable-stream.h"

+ Inheritance diagram for ns3::UniformRandomVariable:
+ Collaboration diagram for ns3::UniformRandomVariable:

Public Member Functions

 UniformRandomVariable ()
 Creates a uniform distribution RNG with the default range.
 
uint32_t GetInteger () override
 Get the next random value drawn from the distribution.
 
uint32_t GetInteger (uint32_t min, uint32_t max)
 Get the next random value drawn from the distribution.
 
double GetMax () const
 Get the upper bound on values returned by GetValue().
 
double GetMin () const
 Get the lower bound on randoms returned by GetValue().
 
double GetValue () override
 Get the next random value drawn from the distribution.
 
double GetValue (double min, double max)
 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.
 
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 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_max
 The upper bound on values that can be returned by this RNG stream.
 
double m_min
 The lower bound on values that can be returned by this RNG stream.
 

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
 Ensure the TypeId for ObjectBase gets fully configured to anchor the inheritance tree properly.
 

Detailed Description

The uniform distribution Random Number Generator (RNG).

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

The output range is $ x \in $ [Min, Max) for floating point values, (Max excluded), and $ x \in $ [Min, Max] (Max included) for integral values.

This distribution has mean

\[ \mu = \frac{\text{Max} + \text{Min}}{2} \]

and variance

\[ \sigma^2 = \frac{\left(\text{Max} - \text{Min}\right)^2}{12} \]

The uniform RNG value $x$ is generated by

\[ x = \text{Min} + u (\text{Max} - \text{Min}) \]

where $u$ is a uniform random variable on [0,1).

Example

Here is an example of how to use this class:

double min = 0.0;
double max = 10.0;
Ptr<UniformRandomVariable> x = CreateObject<UniformRandomVariable> ();
x->SetAttribute ("Min", DoubleValue (min));
x->SetAttribute ("Max", DoubleValue (max));
double value = x->GetValue ();
ns3::DoubleValue
This class can be used to hold variables of floating point type such as 'double' or 'float'.
Definition double.h:31
ns3::Ptr
Smart pointer class similar to boost::intrusive_ptr.
Definition mpi-test-fixtures.h:37
ns3::CreateObject
Ptr< T > CreateObject(Args &&... args)
Create an object by type, with varying number of constructor parameters.
Definition object.h:619
Antithetic Values.

Normally this RNG returns values $x$ for floating point values (or $k$ for integer values) uniformly in the interval [Min, Max) (or [Min, Max] for integer values). If an instance of this RNG is configured to return antithetic values, the actual value returned is calculated as follows:

  • Compute the initial random value $x$ as normal.
  • Compute the distance from the maximum, $y = \text{Max} - x$
  • Return $x' = \text{Min} + y = \text{Min} + (\text{Max} - x)$:

Definition at line 223 of file random-variable-stream.h.

Constructor & Destructor Documentation

◆ UniformRandomVariable()

ns3::UniformRandomVariable::UniformRandomVariable ( )

Creates a uniform distribution RNG with the default range.

Definition at line 166 of file random-variable-stream.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

◆ GetInteger() [1/2]

uint32_t ns3::UniformRandomVariable::GetInteger ( )
overridevirtual

Get the next random value drawn from the distribution.

Returns
A random value.
Note
The upper limit is excluded from the output range, unlike GetInteger().
The upper limit is included in the output range, unlike GetValue().

Reimplemented from ns3::RandomVariableStream.

Definition at line 214 of file random-variable-stream.cc.

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

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◆ GetInteger() [2/2]

uint32_t ns3::UniformRandomVariable::GetInteger ( uint32_t min,
uint32_t max )

Get the next random value drawn from the distribution.

Returns
A random value.
Note
The upper limit is excluded from the output range, unlike GetInteger().
Parameters
[in]minLow end of the range (included).
[in]maxHigh end of the range (excluded).
Note
The upper limit is included in the output range, unlike GetValue(double,double).

Definition at line 198 of file random-variable-stream.cc.

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

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◆ GetMax()

double ns3::UniformRandomVariable::GetMax ( ) const

Get the upper bound on values returned by GetValue().

Returns
The upper bound on values from GetValue().

Definition at line 179 of file random-variable-stream.cc.

References m_max.

◆ GetMin()

double ns3::UniformRandomVariable::GetMin ( ) const

Get the lower bound on randoms returned by GetValue().

Returns
The lower bound on values from GetValue().

Definition at line 173 of file random-variable-stream.cc.

References m_min.

◆ GetTypeId()

TypeId ns3::UniformRandomVariable::GetTypeId ( )
static

Register this type.

Returns
The object TypeId.

Definition at line 146 of file random-variable-stream.cc.

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

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◆ GetValue() [1/2]

double ns3::UniformRandomVariable::GetValue ( )
overridevirtual

Get the next random value drawn from the distribution.

Returns
A random value.
Note
The upper limit is excluded from the output range, unlike GetInteger().

Implements ns3::RandomVariableStream.

Definition at line 208 of file random-variable-stream.cc.

References GetValue(), m_max, and m_min.

Referenced by GetInteger(), GetInteger(), and GetValue().

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◆ GetValue() [2/2]

double ns3::UniformRandomVariable::GetValue ( double min,
double max )

Get the next random value drawn from the distribution.

Returns
A random value.
Note
The upper limit is excluded from the output range, unlike GetInteger().
Parameters
[in]minLow end of the range (included).
[in]maxHigh end of the range (excluded).

Definition at line 185 of file random-variable-stream.cc.

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

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Member Data Documentation

◆ m_max

double ns3::UniformRandomVariable::m_max
private

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

Definition at line 281 of file random-variable-stream.h.

Referenced by GetInteger(), GetMax(), GetTypeId(), and GetValue().

◆ m_min

double ns3::UniformRandomVariable::m_min
private

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

Definition at line 278 of file random-variable-stream.h.

Referenced by GetInteger(), GetMin(), GetTypeId(), and GetValue().

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