Erlang Distributed Random VariableErlangVariable defines a random variable with Erlang distribution. More...

#include <random-variable.h>

Inheritance diagram for ns3::ErlangVariable:

Collaboration diagram for ns3::ErlangVariable:

Public Member Functions
	ErlangVariable ()
	Constructs an Erlang random variable with k = 1 and lambda = 1.0. More...

	ErlangVariable (unsigned int k, double lambda)

double	GetValue (void) const
	call RandomVariable::GetValue More...

double	GetValue (unsigned int k, double lambda) const
	Returns an Erlang random distributed double with parameters k and lambda. More...

Public Member Functions inherited from ns3::RandomVariable
	RandomVariable ()

	RandomVariable (const RandomVariable &o)

	~RandomVariable ()

uint32_t	GetInteger (void) const
	Returns a random integer integer from the underlying distribution. More...

double	GetValue (void) const
	Returns a random double from the underlying distribution. More...

RandomVariable &	operator= (const RandomVariable &o)

Additional Inherited Members
Protected Member Functions inherited from ns3::RandomVariable
	RandomVariable (const RandomVariableBase &variable)

RandomVariableBase *	Peek (void) const

Detailed Description

Erlang Distributed Random Variable

ErlangVariable defines a random variable with Erlang distribution.

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.

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 probability density function is defined over the interval [0,+inf) as: $\frac{x^{k-1} e^{-\frac{x}{\lambda}}}{\lambda^k (k-1)!}$ where $mean = k \lambda$ and $variance = k \lambda^2$

Definition at line 624 of file random-variable.h.

Constructor & Destructor Documentation

ns3::ErlangVariable::ErlangVariable ( )

Constructs an Erlang random variable with k = 1 and lambda = 1.0.

Definition at line 1731 of file random-variable.cc.

References NS_LOG_FUNCTION.

ns3::ErlangVariable::ErlangVariable	(	unsigned int	k,
		double	lambda
	)

Parameters

k	k parameter of the Erlang distribution. Must be a non-negative integer.
lambda	lambda parameter of the Erlang distribution

Definition at line 1737 of file random-variable.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

double ns3::ErlangVariable::GetValue ( void ) const

call RandomVariable::GetValue

Returns: A floating point random value

Note: we have to re-implement this method here because the method is overloaded below for the two-argument variant and the c++ name resolution rules don't work well with overloads split between parent and child classes.

Definition at line 1743 of file random-variable.cc.

References ns3::RandomVariable::GetValue(), and NS_LOG_FUNCTION.

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