A Discrete-Event Network Simulator
API
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Groups Pages
ns3::ZipfVariable Class Reference

Zipf Distributed Random VariableZipfVariable defines a discrete random variable with Zipf distribution. More...

#include <random-variable.h>

+ Inheritance diagram for ns3::ZipfVariable:

Public Member Functions

 ZipfVariable (long N, double alpha)
 Returns a Zipf random variable with parameters N and alpha. More...
 
 ZipfVariable ()
 
- Public Member Functions inherited from ns3::RandomVariable
 RandomVariable (const RandomVariable &o)
 
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...
 
RandomVariableoperator= (const RandomVariable &o)
 

Additional Inherited Members

- Protected Member Functions inherited from ns3::RandomVariable
 RandomVariable (const RandomVariableBase &variable)
 
RandomVariableBasePeek (void) const
 

Detailed Description

Zipf Distributed Random Variable

ZipfVariable defines a discrete random variable with Zipf distribution.

The Zipf's law states that given some corpus of natural language utterances, the frequency of any word is inversely proportional to its rank in the frequency table.

Zipf's distribution have two parameters, alpha and N, where: $ \alpha > 0 $ (real) and $ N \in \{1,2,3 \dots\}$ (integer). Probability Mass Function is $ f(k; \alpha, N) = k^{-\alpha}/ H_{N,\alpha} $ where $ H_{N,\alpha} = \sum_{n=1}^N n^{-\alpha} $

Definition at line 671 of file random-variable.h.

Constructor & Destructor Documentation

ns3::ZipfVariable::ZipfVariable ( long  N,
double  alpha 
)

Returns a Zipf random variable with parameters N and alpha.

Parameters
Nthe number of possible items. Must be a positive integer.
alphathe alpha parameter. Must be a strictly positive real.

Definition at line 1919 of file random-variable.cc.

References NS_LOG_FUNCTION.

ns3::ZipfVariable::ZipfVariable ( )

Constructs a Zipf random variable with N=1 and alpha=0.

Definition at line 1913 of file random-variable.cc.

References NS_LOG_FUNCTION.


The documentation for this class was generated from the following files: