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EST_DiscreteProbDistribution Class Reference

#include <include/EST_simplestats.h>

Public Member Functions

 EST_DiscreteProbDistribution (const EST_DiscreteProbDistribution &b)
 Create with copying from an existing distribution.
 
 EST_DiscreteProbDistribution (const EST_TList< EST_String > &vocab)
 Create with given vocabulary.
 
 EST_DiscreteProbDistribution (const EST_Discrete *d)
 Create using given {EST_Discrete} class as the vocabulary.
 
 EST_DiscreteProbDistribution (const EST_Discrete *d, const double n_samples, const EST_DVector &counts)
 
 ~EST_DiscreteProbDistribution ()
 Destructor function.
 
void copy (const EST_DiscreteProbDistribution &b)
 Copy all data from another DPD to this.
 
void clear (void)
 Reset, clearing all counts and vocabulary.
 
bool init (const EST_StrList &vocab)
 Initialise using given vocabulary.
 
void init (const EST_Discrete *d)
 Initialise using given {EST_Discrete} as vocabulary.
 
void init ()
 Initialise.
 
double samples (void) const
 Total number of example found.
 
void cumulate (const EST_String &s, double count=1)
 Add this observation, may specify number of occurrences.
 
void cumulate (EST_Litem *i, double count=1)
 Add this observation, i must be with in EST_Discrete range.
 
void cumulate (int i, double count=1)
 
const EST_String & most_probable (double *prob=NULL) const
 Return the most probable member of the distribution.
 
double entropy (void) const
 
double probability (const EST_String &s) const
 
double probability (const int i) const
 
double frequency (const EST_String &s) const
 
double frequency (const int i) const
 
EST_Litem * item_start () const
 Used for iterating through members of the distribution.
 
EST_Litem * item_next (EST_Litem *idx) const
 Used for iterating through members of the distribution.
 
int item_end (EST_Litem *idx) const
 Used for iterating through members of the distribution.
 
const EST_String & item_name (EST_Litem *idx) const
 During iteration returns name given index.
 
void item_freq (EST_Litem *idx, EST_String &s, double &freq) const
 During iteration returns name and frequency given index.
 
void item_prob (EST_Litem *idx, EST_String &s, double &prob) const
 During iteration returns name and probability given index.
 
const EST_Discrete *const get_discrete () const
 Returns discrete vocabulary of distribution.
 
void set_frequency (const EST_String &s, double c)
 
void set_frequency (int i, double c)
 
void set_frequency (EST_Litem *i, double c)
 
void override_frequency (const EST_String &s, double c)
 Sets the frequency of named item, without modifying { num_samples}.
 
void override_frequency (int i, double c)
 Sets the frequency of named item, without modifying { num_samples}.
 
void override_frequency (EST_Litem *i, double c)
 
void set_num_samples (const double c)
 
EST_DiscreteProbDistribution & operator= (const EST_DiscreteProbDistribution &a)
 

Friends

ostream & operator<< (ostream &s, const EST_DiscreteProbDistribution &p)
 

Detailed Description

A class for representing probability distributions for a set of discrete values.

This may be used to cummulate the probability distribution of a class of values. Values are actually help as frequencies so both frequency and probability information may be available. Note that frequencies are not integers because using smoothing and backoff integers are too restrictive so they are actually represented as doubles.

Methods are provided to iterate over the values in a distribution, for example {verbatim} EST_DiscreteProbistribution pdf; for (int i=pdf.item_start(); i < pdf.item_end(); i=pdf.item_next(i)) { EST_String name; double prob; item_prob(i,name,prob); cout << name << ": prob " << prob << endl; } {verbatim}

Author
Alan W Black (awb@c.nosp@m.str..nosp@m.ed.ac.nosp@m..uk): July 1996

Definition at line 210 of file EST_simplestats.h.

Constructor & Destructor Documentation

EST_DiscreteProbDistribution::EST_DiscreteProbDistribution ( const EST_Discrete *  d,
const double  n_samples,
const EST_DVector &  counts 
)

Create using given {EST_Discrete} class as vocabulary plus given counts

Definition at line 82 of file EST_DProbDist.cc.

Member Function Documentation

double EST_DiscreteProbDistribution::entropy ( void  ) const

Return the entropy of the distribution [ -{i=1}^N(prob(i)*log(prob(i))) ]

Definition at line 339 of file EST_DProbDist.cc.

void EST_DiscreteProbDistribution::set_frequency ( const EST_String &  s,
double  c 
)

Sets the frequency of named item, modifies { num_samples} accordingly. This is used when smoothing frequencies.

Definition at line 268 of file EST_DProbDist.cc.

void EST_DiscreteProbDistribution::set_frequency ( int  i,
double  c 
)

Sets the frequency of named item, modifies { num_samples} accordingly. This is used when smoothing frequencies.

Definition at line 284 of file EST_DProbDist.cc.

void EST_DiscreteProbDistribution::set_num_samples ( const double  c)
inline

Sets the number of samples. Care should be taken on setting this as it will affect how probabilities are calculated.

Definition at line 306 of file EST_simplestats.h.

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