The exponential distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically. More...
#include <random-variable-stream.h>
Public Member Functions | |
ExponentialRandomVariable () | |
Creates a exponential distribution RNG with the default values for the mean and upper bound. | |
double | GetBound (void) const |
Returns the upper bound on values that can be returned by this RNG stream. More... | |
uint32_t | GetInteger (uint32_t mean, uint32_t bound) |
Returns a random unsigned integer from an exponential distribution with the specified mean and upper bound. More... | |
virtual uint32_t | GetInteger (void) |
Returns a random unsigned integer from an exponential distribution with the current mean and upper bound. More... | |
double | GetMean (void) const |
Returns the mean value of the random variables returned by this RNG stream. More... | |
double | GetValue (double mean, double bound) |
Returns a random double from an exponential distribution with the specified mean and upper bound. More... | |
virtual double | GetValue (void) |
Returns a random double from an exponential distribution with the current mean and upper bound. More... | |
Public Member Functions inherited from ns3::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... | |
Public Member Functions inherited from ns3::Object | |
void | AggregateObject (Ptr< Object > other) |
void | Dispose (void) |
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) |
Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter > | |
SimpleRefCount (const SimpleRefCount &o) | |
uint32_t | GetReferenceCount (void) const |
SimpleRefCount & | operator= (const SimpleRefCount &o) |
void | Ref (void) const |
void | Unref (void) const |
Public Member Functions inherited from ns3::ObjectBase | |
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) |
Static Public Member Functions inherited from ns3::RandomVariableStream | |
static TypeId | GetTypeId (void) |
Static Public Member Functions inherited from ns3::Object | |
static TypeId | GetTypeId (void) |
Static Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter > | |
static void | Cleanup (void) |
Static Public Member Functions inherited from ns3::ObjectBase | |
static TypeId | GetTypeId (void) |
Private Attributes | |
double | m_bound |
The upper bound on values that can be returned by this RNG stream. | |
double | m_mean |
The mean value of the random variables returned by this RNG stream. | |
Additional Inherited Members | |
Protected Member Functions inherited from ns3::RandomVariableStream | |
RngStream * | Peek (void) const |
Returns a pointer to the underlying RNG stream. | |
Protected Member Functions inherited from ns3::Object | |
Object (const Object &o) | |
virtual void | DoDispose (void) |
virtual void | DoInitialize (void) |
virtual void | NotifyNewAggregate (void) |
Protected Member Functions inherited from ns3::ObjectBase | |
void | ConstructSelf (const AttributeConstructionList &attributes) |
virtual void | NotifyConstructionCompleted (void) |
The exponential 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 exponential distribution. It also supports the generation of single random numbers from various exponential distributions.
The probability density function of an exponential variable is defined over the interval [0, ) as: where
Since exponential distributions can theoretically return unbounded values, it is sometimes useful to specify a fixed upper limit. The bounded version is defined over the interval [0,b] as: . Note that in this case the true mean of the distribution is slightly smaller than the mean value specified: .
Here is an example of how to use this class:
ns3::ExponentialRandomVariable is accessible through the following paths with Config::Set and Config::Connect:
No TraceSources are defined for this type.
Definition at line 440 of file random-variable-stream.h.
double ns3::ExponentialRandomVariable::GetBound | ( | void | ) | const |
Returns the upper bound on values that can be returned by this RNG stream.
Definition at line 388 of file random-variable-stream.cc.
References m_bound, and NS_LOG_FUNCTION.
uint32_t ns3::ExponentialRandomVariable::GetInteger | ( | uint32_t | mean, |
uint32_t | bound | ||
) |
Returns a random unsigned integer 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 418 of file random-variable-stream.cc.
References GetValue(), and NS_LOG_FUNCTION.
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virtual |
Returns a random unsigned integer from an exponential distribution with the current mean and upper bound.
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.
Implements ns3::RandomVariableStream.
Definition at line 431 of file random-variable-stream.cc.
References GetValue(), m_bound, m_mean, and NS_LOG_FUNCTION.
double ns3::ExponentialRandomVariable::GetMean | ( | void | ) | const |
Returns the mean value of the random variables returned by this RNG stream.
Definition at line 382 of file random-variable-stream.cc.
References m_mean, and NS_LOG_FUNCTION.
double ns3::ExponentialRandomVariable::GetValue | ( | double | mean, |
double | bound | ||
) |
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 395 of file random-variable-stream.cc.
References ns3::RandomVariableStream::IsAntithetic(), NS_LOG_FUNCTION, ns3::RandomVariableStream::Peek(), and ns3::RngStream::RandU01().
Referenced by RandomVariableStreamExponentialTestCase::DoRun(), and RandomVariableStreamExponentialAntitheticTestCase::DoRun().
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virtual |
Returns a random double from an exponential distribution with the current mean and upper bound.
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.
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 425 of file random-variable-stream.cc.
References m_bound, m_mean, and NS_LOG_FUNCTION.
Referenced by GetInteger().