The Erlang distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically. More...
#include <random-variable-stream.h>
Public Member Functions | |
ErlangRandomVariable () | |
Creates an Erlang distribution RNG with the default values for k and lambda. More... | |
uint32_t | GetInteger (uint32_t k, uint32_t lambda) |
Returns a random unsigned integer from an Erlang distribution with the specified k and lambda. More... | |
virtual uint32_t | GetInteger (void) |
Returns a random unsigned integer from an Erlang distribution with the current k and lambda. More... | |
uint32_t | GetK (void) const |
Returns the k value for the Erlang distribution returned by this RNG stream. More... | |
double | GetLambda (void) const |
Returns the lambda value for the Erlang distribution returned by this RNG stream. More... | |
double | GetValue (uint32_t k, double lambda) |
Returns a random double from an Erlang distribution with the specified k and lambda. More... | |
virtual double | GetValue (void) |
Returns a random double from an Erlang distribution with the current k and lambda. More... | |
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RandomVariableStream () | |
virtual | ~RandomVariableStream () |
int64_t | GetStream (void) const |
Returns the stream number for this RNG stream. More... | |
bool | IsAntithetic (void) const |
Returns true if antithetic values should be generated. More... | |
void | SetAntithetic (bool isAntithetic) |
Specifies whether antithetic values should be generated. More... | |
void | SetStream (int64_t stream) |
Specifies the stream number for this RNG stream. More... | |
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Object () | |
virtual | ~Object () |
void | AggregateObject (Ptr< Object > other) |
void | Dispose (void) |
Run the DoDispose methods of this object and all the objects aggregated to it. More... | |
AggregateIterator | GetAggregateIterator (void) const |
virtual TypeId | GetInstanceTypeId (void) const |
template<typename T > | |
Ptr< T > | GetObject (void) const |
template<typename T > | |
Ptr< T > | GetObject (TypeId tid) const |
void | Initialize (void) |
This method calls the virtual DoInitialize method on all the objects aggregated to this object. More... | |
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SimpleRefCount () | |
Constructor. More... | |
SimpleRefCount (const SimpleRefCount &o) | |
Copy constructor. More... | |
uint32_t | GetReferenceCount (void) const |
Get the reference count of the object. More... | |
SimpleRefCount & | operator= (const SimpleRefCount &o) |
Assignment. More... | |
void | Ref (void) const |
Increment the reference count. More... | |
void | Unref (void) const |
Decrement the reference count. More... | |
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virtual | ~ObjectBase () |
Virtual destructor. More... | |
void | GetAttribute (std::string name, AttributeValue &value) const |
bool | GetAttributeFailSafe (std::string name, AttributeValue &attribute) const |
void | SetAttribute (std::string name, const AttributeValue &value) |
bool | SetAttributeFailSafe (std::string name, const AttributeValue &value) |
bool | TraceConnect (std::string name, std::string context, const CallbackBase &cb) |
bool | TraceConnectWithoutContext (std::string name, const CallbackBase &cb) |
bool | TraceDisconnect (std::string name, std::string context, const CallbackBase &cb) |
bool | TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb) |
Static Public Member Functions | |
static TypeId | GetTypeId (void) |
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static TypeId | GetTypeId (void) |
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static TypeId | GetTypeId (void) |
Register this type. More... | |
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static void | Cleanup (void) |
Noop. More... | |
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static TypeId | GetTypeId (void) |
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 | |
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RngStream * | Peek (void) const |
Returns a pointer to the underlying RNG stream. More... | |
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Object (const Object &o) | |
virtual void | DoDispose (void) |
This method is called by Object::Dispose or by the object's destructor, whichever comes first. More... | |
virtual void | DoInitialize (void) |
This method is called only once by Object::Initialize. More... | |
virtual void | NotifyNewAggregate (void) |
This method is invoked whenever two sets of objects are aggregated together. More... | |
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void | ConstructSelf (const AttributeConstructionList &attributes) |
virtual void | NotifyConstructionCompleted (void) |
This method is invoked once all member attributes have been initialized. 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 k (= alpha) is a non-negative integer. Erlang distributed variables can be generated using a much faster algorithm than gamma variables.
The probability density function is defined over the interval [0, ) as:
where
and
Here is an example of how to use this class:
ns3::ErlangRandomVariable is accessible through the following paths with Config::Set and Config::Connect:
No TraceSources are defined for this type.
Definition at line 1671 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 1068 of file random-variable-stream.cc.
References NS_LOG_FUNCTION.
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private |
Returns a random double from an exponential distribution with the specified mean and upper bound.
mean | Mean value of the random variables. |
bound | Upper bound on values returned. |
Note that antithetic values are being generated if m_isAntithetic is equal to true. If is a uniform variable over [0,1] and
is a value that would be returned normally, then ) is the distance that
would be from
. The value returned in the antithetic case,
, is calculated as
which now involves the log of the distance is from the 1.
Definition at line 1137 of file random-variable-stream.cc.
References ns3::RandomVariableStream::IsAntithetic(), NS_LOG_FUNCTION, ns3::RandomVariableStream::Peek(), and ns3::RngStream::RandU01().
Referenced by GetValue().
uint32_t ns3::ErlangRandomVariable::GetInteger | ( | uint32_t | k, |
uint32_t | lambda | ||
) |
Returns a random unsigned integer from an Erlang distribution with the specified k and lambda.
k | K value for the Erlang distribution. |
lambda | Lambda value for the Erlang distribution. |
Note that antithetic values are being generated if m_isAntithetic is equal to true. If is a uniform variable over [0,1] and
is a value that would be returned normally, then
) is the distance that
would be from
. The value returned in the antithetic case,
, uses (1-u), which is the distance
is from the 1.
Definition at line 1117 of file random-variable-stream.cc.
References GetValue(), and NS_LOG_FUNCTION.
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virtual |
Returns a random unsigned integer from an Erlang distribution with the current k and lambda.
Note that antithetic values are being generated if m_isAntithetic is equal to true. If is a uniform variable over [0,1] and
is a value that would be returned normally, then
) is the distance that
would be from
. The value returned in the antithetic case,
, uses (1-u), which is the distance
is from the 1.
Implements ns3::RandomVariableStream.
Definition at line 1130 of file random-variable-stream.cc.
References GetValue(), m_k, m_lambda, and NS_LOG_FUNCTION.
uint32_t ns3::ErlangRandomVariable::GetK | ( | void | ) | const |
Returns the k value for the Erlang distribution returned by this RNG stream.
Definition at line 1075 of file random-variable-stream.cc.
References m_k, and NS_LOG_FUNCTION.
double ns3::ErlangRandomVariable::GetLambda | ( | void | ) | const |
Returns the lambda value for the Erlang distribution returned by this RNG stream.
Definition at line 1081 of file random-variable-stream.cc.
References m_lambda, and NS_LOG_FUNCTION.
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static |
Definition at line 1052 of file random-variable-stream.cc.
References m_k, m_lambda, and ns3::TypeId::SetParent().
double ns3::ErlangRandomVariable::GetValue | ( | uint32_t | k, |
double | lambda | ||
) |
Returns a random double from an Erlang distribution with the specified k and lambda.
k | K value for the Erlang distribution. |
lambda | Lambda value for the Erlang distribution. |
Note that antithetic values are being generated if m_isAntithetic is equal to true. If is a uniform variable over [0,1] and
is a value that would be returned normally, then
) is the distance that
would be from
. The value returned in the antithetic case,
, uses (1-u), which is the distance
is from the 1.
Definition at line 1100 of file random-variable-stream.cc.
References GetExponentialValue(), and NS_LOG_FUNCTION.
Referenced by RandomVariableStreamErlangTestCase::ChiSquaredTest(), RandomVariableStreamErlangAntitheticTestCase::ChiSquaredTest(), RandomVariableStreamErlangTestCase::DoRun(), and RandomVariableStreamErlangAntitheticTestCase::DoRun().
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virtual |
Returns a random double from an Erlang distribution with the current k and lambda.
Note that antithetic values are being generated if m_isAntithetic is equal to true. If is a uniform variable over [0,1] and
is a value that would be returned normally, then
) is the distance that
would be from
. The value returned in the antithetic case,
, uses (1-u), which is the distance
is from the 1.
Note that we have to re-implement this method here because the method is overloaded above for the two-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 1124 of file random-variable-stream.cc.
References m_k, m_lambda, and NS_LOG_FUNCTION.
Referenced by GetInteger().
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private |
The k value for the Erlang distribution returned by this RNG stream.
Definition at line 1783 of file random-variable-stream.h.
Referenced by GetInteger(), GetK(), GetTypeId(), and GetValue().
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private |
The lambda value for the Erlang distribution returned by this RNG stream.
Definition at line 1786 of file random-variable-stream.h.
Referenced by GetInteger(), GetLambda(), GetTypeId(), and GetValue().