itpp::Vector_Quantizer Class Reference

Class for vector quantization. More...

#include <itpp/srccode/vq.h>

Public Member Functions
	Vector_Quantizer ()
	Default constructor.
	Vector_Quantizer (const char *Name)
	Create a VQ from a VQ file.
int	encode (const vec &x)
	Encode the input vector.
ivec	encode (const vec &x, int num)
	Encode the input vector, and return the num best indices.
vec	decode (int Index) const
	Decode the index.
Array< vec >	decode (const ivec &Index) const
	Decode the indices.
vec	Q (const vec &x)
	Quantize the input vector.
vec	operator() (const vec &x)
	Quantize the input vector.
void	set_codebook (const mat &CB)
	Initialize the codebook by a matrix.
mat	get_codebook () const
	Returns the codebook.
void	set_codevector (int Index, const vec &indata)
	Set a codevector in the codebook.
vec	get_codevector (int Index) const
	Returns the codevector at the given index.
void	modify_codevector (int no, double mul, const vec &add)
	Rescale and translate a codevector.
int	size () const
	Returns the size (number of codevectors) of the VQ.
int	dim () const
	Returns the dimension of the VQ.
int	nobits () const
	Returns the number of bits of the VQ [log2(size)/dim].
void	load (const char *Name)
	Load the codebook from a file.
void	save (const char *Name) const
	Save the codebook to a file.
double	latest_distortion ()
	Returns the distortion at the latest time a vector was encoded.

Protected Attributes
vec	CodeBook
	The vector containing the code book.
int	Size
	The size of the code book.
int	Dim
	The dimension of the code book.
double	LatestDist
	The distortion at the latest time a vector was encoded.

Detailed Description

Class for vector quantization.

The following code illustrates how the VQ can be initialized from a file and used to quantize a random vector.

Vector_Quantizer Quantizer;
vec     x,y;
int     i;

Quantizer.load("randomvq.vq");
x=randn(Quantizer.dim());
i=Quantizer.encode(x);
y=Quantizer.decode(i);

Definition at line 62 of file vq.h.

Member Function Documentation

void itpp::Vector_Quantizer::load

(

const char *

Name

)

Load the codebook from a file.

Parameters

Name	The name of the VQ file

The file format is a textfile where each row is a vector from the codebook.

void itpp::Vector_Quantizer::save

(

const char *

Name

)

const

Save the codebook to a file.

Parameters

Name	The name of the VQ file

The file format is a textfile where each row is a vector from the codebook.

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

• itpp/srccode/vq.h