The gamma distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically. More...
#include "random-variable-stream.h"
Inheritance diagram for ns3::GammaRandomVariable:
Collaboration diagram for ns3::GammaRandomVariable:Public Member Functions | |
| GammaRandomVariable () | |
| Creates a gamma distribution RNG with the default values for alpha and beta. More... | |
| double | GetAlpha () const |
| Returns the alpha value for the gamma distribution returned by this RNG stream. More... | |
| double | GetBeta () const |
| Returns the beta value for the gamma distribution returned by this RNG stream. More... | |
| virtual uint32_t | GetInteger () |
| Get the next random value drawn from the distribution. More... | |
| uint32_t | GetInteger (uint32_t alpha, uint32_t beta) |
| Get the next random value drawn from the distribution. More... | |
| double | GetValue () override |
| Get the next random value drawn from the distribution. More... | |
| double | GetValue (double alpha, double beta) |
| 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... | |
| int64_t | GetStream () const |
| Returns the stream number for the RngStream. 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[[maybe_unused]]) | |
| Copy constructor. More... | |
| uint32_t | GetReferenceCount () const |
| Get the reference count of the object. More... | |
| SimpleRefCount & | operator= (const SimpleRefCount &o[[maybe_unused]]) |
| 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... | |
| 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 | GetNormalValue (double mean, double variance, double bound) |
| Returns a random double from a normal distribution with the specified mean, variance, and bound. More... | |
Private Attributes | |
| double | m_alpha |
| The alpha value for the gamma distribution returned by this RNG stream. More... | |
| double | m_beta |
| The beta value for the gamma distribution returned by this RNG stream. More... | |
| bool | m_nextValid |
| True if the next normal value is valid. More... | |
| double | m_v2 |
| The algorithm produces two values at a time. More... | |
| double | m_y |
| The algorithm produces two values at a time. 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 gamma 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 gamma distribution. It also supports the generation of single random numbers from various gamma distributions.
The probability distribution is defined in terms two parameters, Alpha =
and Beta =
. (Note the Wikipedia entry for the Gamma Distribution uses either the parameters
or
. The parameters used here
correspond to
.)
The probability density function is:
where the mean is
and the variance is
.
While gamma RNG values can be generated by an algorithm similar to normal RNGs, the implementation used here is based on the paper G. Marsaglia and W. W. Tsang, A simple method for generating Gamma variables, ACM Transactions on Mathematical Software, Vol. 26, No. 3, Sept. 2000.
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 using the prescription in the Marsaglia, et al. paper cited above.
ns3::GammaRandomVariable is accessible through the following paths with Config::Set and Config::Connect:
No TraceSources are defined for this type.
Size of this type is 96 bytes (on a 64-bit architecture).
Definition at line 1234 of file random-variable-stream.h.
| ns3::GammaRandomVariable::GammaRandomVariable | ( | ) |
Creates a gamma distribution RNG with the default values for alpha and beta.
Definition at line 925 of file random-variable-stream.cc.
References NS_LOG_FUNCTION.
| double ns3::GammaRandomVariable::GetAlpha | ( | ) | const |
Returns the alpha value for the gamma distribution returned by this RNG stream.
Definition at line 934 of file random-variable-stream.cc.
References m_alpha, and NS_LOG_FUNCTION.
| double ns3::GammaRandomVariable::GetBeta | ( | ) | const |
Returns the beta value for the gamma distribution returned by this RNG stream.
Definition at line 941 of file random-variable-stream.cc.
References m_beta, and NS_LOG_FUNCTION.
|
virtual |
Get the next random value drawn from the distribution.
Reimplemented from ns3::RandomVariableStream.
Definition at line 153 of file random-variable-stream.cc.
| uint32_t ns3::GammaRandomVariable::GetInteger | ( | uint32_t | alpha, |
| uint32_t | beta | ||
| ) |
Get the next random value drawn from the distribution.
| [in] | alpha | Alpha value for the gamma distribution. |
| [in] | beta | Beta value for the gamma distribution. |
|
private |
Returns a random double from a normal distribution with the specified mean, variance, and bound.
| [in] | mean | Mean value for the normal distribution. |
| [in] | variance | Variance value for the normal distribution. |
| [in] | bound | Bound on values returned. |
Definition at line 1024 of file random-variable-stream.cc.
References ns3::RandomVariableStream::IsAntithetic(), m_nextValid, m_v2, m_y, NS_LOG_FUNCTION, ns3::RandomVariableStream::Peek(), and ns3::RngStream::RandU01().
Referenced by GetValue().
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|
static |
Register this type.
Definition at line 905 of file random-variable-stream.cc.
References m_alpha, m_beta, ns3::MakeDoubleAccessor(), and ns3::TypeId::SetParent().
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overridevirtual |
Get the next random value drawn from the distribution.
Implements ns3::RandomVariableStream.
Definition at line 1017 of file random-variable-stream.cc.
References m_alpha, m_beta, and NS_LOG_FUNCTION.
Referenced by GetValue().
Here is the caller graph for this function:| double ns3::GammaRandomVariable::GetValue | ( | double | alpha, |
| double | beta | ||
| ) |
Get the next random value drawn from the distribution.
| [in] | alpha | Alpha value for the gamma distribution. |
| [in] | beta | Beta value for the gamma distribution. |
Definition at line 964 of file random-variable-stream.cc.
References GetNormalValue(), GetValue(), ns3::NormalRandomVariable::INFINITE_VALUE, ns3::RandomVariableStream::IsAntithetic(), NS_LOG_FUNCTION, ns3::RandomVariableStream::Peek(), ns3::RngStream::RandU01(), and two-ray-to-three-gpp-ch-calibration::x.
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private |
The alpha value for the gamma distribution returned by this RNG stream.
Definition at line 1287 of file random-variable-stream.h.
Referenced by GetAlpha(), GetTypeId(), and GetValue().
|
private |
The beta value for the gamma distribution returned by this RNG stream.
Definition at line 1290 of file random-variable-stream.h.
Referenced by GetBeta(), GetTypeId(), and GetValue().
|
private |
True if the next normal value is valid.
Definition at line 1293 of file random-variable-stream.h.
Referenced by GetNormalValue().
|
private |
The algorithm produces two values at a time.
Cache parameters for possible reuse.
Definition at line 1296 of file random-variable-stream.h.
Referenced by GetNormalValue().
|
private |
The algorithm produces two values at a time.
Cache parameters for possible reuse.
Definition at line 1298 of file random-variable-stream.h.
Referenced by GetNormalValue().