The Erlang distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically. More...
#include "random-variable-stream.h"
Inheritance diagram for ns3::ErlangRandomVariable:
Collaboration diagram for ns3::ErlangRandomVariable:Public Member Functions | |
| ErlangRandomVariable () | |
| Creates an Erlang distribution RNG with the default values for k and lambda. More... | |
| virtual uint32_t | GetInteger () |
| Get the next random value drawn from the distribution. More... | |
| uint32_t | GetInteger (uint32_t k, uint32_t lambda) |
| Get the next random value drawn from the distribution. More... | |
| uint32_t | GetK () const |
| Returns the k value for the Erlang distribution returned by this RNG stream. More... | |
| double | GetLambda () const |
| Returns the lambda value for the Erlang distribution returned by this RNG stream. More... | |
| double | GetValue () override |
| Get the next random value drawn from the distribution. More... | |
| double | GetValue (uint32_t k, double lambda) |
| Get the next random value drawn from the distribution. More... | |
Public Member Functions inherited from ns3::RandomVariableStream | |
| RandomVariableStream () | |
| Default constructor. More... | |
| RandomVariableStream (const RandomVariableStream &)=delete | |
| ~RandomVariableStream () override | |
| Destructor. More... | |
| virtual uint32_t | GetInteger () |
| Get the next random value drawn from the distribution. More... | |
| int64_t | GetStream () const |
| Returns the stream number for the RngStream. More... | |
| virtual double | GetValue ()=0 |
| Get the next random value drawn from the distribution. More... | |
| bool | IsAntithetic () const |
| Check if antithetic values will be generated. More... | |
| RandomVariableStream & | operator= (const RandomVariableStream &)=delete |
| 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... | |
| ~Object () override | |
| Destructor. More... | |
| void | AggregateObject (Ptr< Object > other) |
| Aggregate two Objects together. More... | |
| void | Dispose () |
| Dispose of this Object. More... | |
| AggregateIterator | GetAggregateIterator () const |
| Get an iterator to the Objects aggregated to this one. More... | |
| TypeId | GetInstanceTypeId () const override |
| Get the most derived TypeId for this Object. More... | |
| template<typename T > | |
| Ptr< T > | GetObject () const |
| Get a pointer to the requested aggregated Object. More... | |
| template<> | |
| Ptr< Object > | GetObject () const |
| Specialization of () for objects of type ns3::Object. More... | |
| template<typename T > | |
| Ptr< T > | GetObject (TypeId tid) const |
| Get a pointer to the requested aggregated Object by TypeId. More... | |
| template<> | |
| Ptr< Object > | GetObject (TypeId tid) const |
| Specialization of (TypeId tid) for objects of type ns3::Object. More... | |
| void | Initialize () |
| Invoke DoInitialize on all Objects aggregated to this one. More... | |
| bool | IsInitialized () 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 () const |
| Get the reference count of the object. More... | |
| SimpleRefCount & | operator= (const SimpleRefCount &o) |
| Assignment operator. More... | |
| void | Ref () const |
| Increment the reference count. More... | |
| void | Unref () 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 errors. More... | |
| virtual TypeId | GetInstanceTypeId () const =0 |
| Get the most derived TypeId for this Object. 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 () |
| Register this type. More... | |
Static Public Member Functions inherited from ns3::RandomVariableStream | |
| static TypeId | GetTypeId () |
| Register this type. More... | |
Static Public Member Functions inherited from ns3::Object | |
| static TypeId | GetTypeId () |
| Register this type. More... | |
Static Public Member Functions inherited from ns3::ObjectBase | |
| static TypeId | GetTypeId () |
| Get the type ID. More... | |
Private Member Functions | |
| double | GetExponentialValue (double mean, double bound) |
| Returns a random double from an exponential distribution with the specified mean and upper bound. More... | |
Private Attributes | |
| uint32_t | m_k |
| The k value for the Erlang distribution returned by this RNG stream. More... | |
| double | m_lambda |
| The lambda value for the Erlang distribution returned by this RNG stream. More... | |
Additional Inherited Members | |
Protected Member Functions inherited from ns3::RandomVariableStream | |
| RngStream * | Peek () 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 () |
| Destructor implementation. More... | |
| virtual void | DoInitialize () |
| Initialize() implementation. More... | |
| virtual void | NotifyNewAggregate () |
| 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 () |
| Notifier called once the ObjectBase is fully constructed. More... | |
Related Functions inherited from ns3::ObjectBase | |
| static TypeId | GetObjectIid () |
| Ensure the TypeId for ObjectBase gets fully configured to anchor the inheritance tree properly. More... | |
The Erlang 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 Erlang distribution. It also supports the generation of single random numbers from various Erlang distributions.
The Erlang distribution is a special case of the Gamma distribution where
is a positive definite integer. Erlang distributed variables can be generated using a much faster algorithm than Gamma variables.
The probability distribution is defined in terms two parameters, the K or shape parameter
, and the Lambda or scale parameter
. (Note the Wikipedia entry for the Erlang Distribution uses the parameters
or
. The parameters used here
correspond to
.)
The probability density function is:
with mean
and variance
.
The Erlang RNG value
is generated by
where the
are
uniform random variables on [0,1).
Here is an example of how to use this class:
If an instance of this RNG is configured to return antithetic values, the actual value returned,
, is generated as follows:
which now involves the log of the distance
is from 1.
ns3::ErlangRandomVariable is accessible through the following paths with Config::Set and Config::Connect:
No TraceSources are defined for this type.
Size of this type is 72 bytes (on a 64-bit architecture).
Definition at line 1368 of file random-variable-stream.h.
| ns3::ErlangRandomVariable::ErlangRandomVariable | ( | ) |
Creates an Erlang distribution RNG with the default values for k and lambda.
Definition at line 1098 of file random-variable-stream.cc.
References NS_LOG_FUNCTION.
Returns a random double from an exponential distribution with the specified mean and upper bound.
| [in] | mean | Mean value of the random variables. |
| [in] | bound | Upper bound on values returned. |
Definition at line 1161 of file random-variable-stream.cc.
References ns3::RandomVariableStream::IsAntithetic(), NS_LOG_FUNCTION, ns3::RandomVariableStream::Peek(), and ns3::RngStream::RandU01().
Referenced by GetValue().
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|
virtual |
Get the next random value drawn from the distribution.
Reimplemented from ns3::RandomVariableStream.
Definition at line 153 of file random-variable-stream.cc.
Get the next random value drawn from the distribution.
| [in] | k | K value for the Erlang distribution. |
| [in] | lambda | Lambda value for the Erlang distribution. |
Definition at line 1147 of file random-variable-stream.cc.
References GetValue(), two-ray-to-three-gpp-ch-calibration::k, and NS_LOG_FUNCTION.
Here is the call graph for this function:| uint32_t ns3::ErlangRandomVariable::GetK | ( | ) | const |
Returns the k value for the Erlang distribution returned by this RNG stream.
Definition at line 1105 of file random-variable-stream.cc.
References m_k, and NS_LOG_FUNCTION.
| double ns3::ErlangRandomVariable::GetLambda | ( | ) | const |
Returns the lambda value for the Erlang distribution returned by this RNG stream.
Definition at line 1112 of file random-variable-stream.cc.
References m_lambda, and NS_LOG_FUNCTION.
|
static |
Register this type.
Definition at line 1077 of file random-variable-stream.cc.
References m_k, m_lambda, ns3::MakeDoubleAccessor(), ns3::MakeIntegerAccessor(), and ns3::TypeId::SetParent().
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overridevirtual |
Get the next random value drawn from the distribution.
Implements ns3::RandomVariableStream.
Definition at line 1154 of file random-variable-stream.cc.
References GetValue(), m_k, m_lambda, and NS_LOG_FUNCTION.
Referenced by GetInteger(), and GetValue().
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| [in] | k | K value for the Erlang distribution. |
| [in] | lambda | Lambda value for the Erlang distribution. |
Definition at line 1131 of file random-variable-stream.cc.
References GetExponentialValue(), two-ray-to-three-gpp-ch-calibration::k, and NS_LOG_FUNCTION.
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private |
The k value for the Erlang distribution returned by this RNG stream.
Definition at line 1420 of file random-variable-stream.h.
Referenced by GetK(), GetTypeId(), and GetValue().
|
private |
The lambda value for the Erlang distribution returned by this RNG stream.
Definition at line 1423 of file random-variable-stream.h.
Referenced by GetLambda(), GetTypeId(), and GetValue().