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/*!
* \file
* \brief Definition of a vector quantizer class (unconstrained)
* \author Thomas Eriksson
*
* -------------------------------------------------------------------------
*
* IT++ - C++ library of mathematical, signal processing, speech processing,
* and communications classes and functions
*
* Copyright (C) 1995-2008 (see AUTHORS file for a list of contributors)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* -------------------------------------------------------------------------
*/
#ifndef VQ_H
#define VQ_H
#include <itpp/base/vec.h>
#include <itpp/base/sort.h>
#include <itpp/base/math/log_exp.h>
namespace itpp {
/*!
\addtogroup sourcecoding
*/
/*!
\ingroup sourcecoding
\brief Class for vector quantization
The following code illustrates how the VQ can be initialized from a file and
used to quantize a random vector.
\code
Vector_Quantizer Quantizer;
vec x,y;
int i;
Quantizer.load("randomvq.vq");
x=randn(Quantizer.dim());
i=Quantizer.encode(x);
y=Quantizer.decode(i);
\endcode
*/
class Vector_Quantizer {
public:
//! Default constructor
Vector_Quantizer();
//! Create a VQ from a VQ file
Vector_Quantizer(const char *Name);
//! Encode the input vector
int encode(const vec &x);
//! Encode the input vector, and return the num best indices
ivec encode(const vec &x, int num);
//! Decode the index
vec decode(int Index) const;
//! Decode the indices
Array<vec> decode(const ivec &Index) const;
//! Quantize the input vector
vec Q(const vec &x);
//! Quantize the input vector
vec operator()(const vec &x);
//! Initialize the codebook by a matrix
void set_codebook(const mat &CB);
//! Returns the codebook
mat get_codebook() const;
//! Set a codevector in the codebook
void set_codevector(int Index, const vec &indata);
//! Returns the codevector at the given index
vec get_codevector(int Index) const;
//! Rescale and translate a codevector
void modify_codevector(int no, double mul, const vec &add);
//! Returns the size (number of codevectors) of the VQ
int size() const;
//! Returns the dimension of the VQ
int dim() const;
//! Returns the number of bits of the VQ [log2(size)/dim]
int nobits() const;
/*!
\brief Load the codebook from a file
\param Name The name of the VQ file
The file format is a textfile where each row is a vector from the codebook.
*/
void load(const char *Name);
/*!
\brief Save the codebook to a file
\param Name The name of the VQ file
The file format is a textfile where each row is a vector from the codebook.
*/
void save(const char *Name) const;
//! Returns the distortion at the latest time a vector was encoded
double latest_distortion();
protected:
//! The vector containing the code book
vec CodeBook;
//! The size of the code book
int Size;
//! The dimension of the code book
int Dim;
//! The distortion at the latest time a vector was encoded
double LatestDist;
};
// INLINE FUNCTIONS
inline int Vector_Quantizer::size() const { return Size; }
inline int Vector_Quantizer::nobits() const { return levels2bits(Size); }
inline int Vector_Quantizer::dim() const { return Dim; }
inline double Vector_Quantizer::latest_distortion() { return LatestDist; }
inline vec Vector_Quantizer::decode(int Index) const { return get_codevector(Index); }
inline vec Vector_Quantizer::Q(const vec &x) { return decode(encode(x)); }
inline vec Vector_Quantizer::operator()(const vec &x) { return Q(x); }
/*!
\ingroup sourcecoding
\brief Class for vector quantization
The following code illustrates how the quantizer can be initialized from a file and
used to quantize a random vector.
\code
Scalar_Quantizer Quantizer;
double x,y;
int i;
Quantizer.load("random.sq");
x=randn();
i=Quantizer.encode(x);
y=Quantizer.decode(i);
\endcode
*/
class Scalar_Quantizer {
public:
//! Default constructor
Scalar_Quantizer();
//! Create a VQ from a VQ file
Scalar_Quantizer(const char *Name);
//! Encode
int encode(double x) const;
//! Encode the input vector
ivec encode(const vec &x) const;
//! Decode the index
double decode(int Index) const;
//! Decode the indices
vec decode(const ivec &Index) const;
//! Quantize
double Q(double x) const;
//! Quantize the input vector
vec Q(const vec &x) const;
//! Quantize
double operator()(double x) const;
//! Quantize the input vector
vec operator()(const vec &x) const;
//! Initialize the codebook by a matrix
void set_levels(const vec &L);
//! Returns the codebook
vec get_levels() const;
//! Returns the size (number of codevectors) of the VQ
int size() const;
protected:
//! The vector containing the code book
vec Levels;
//! The distortion at the latest time a vector was encoded
double LatestDist;
};
inline int Scalar_Quantizer::size() const { return Levels.length(); }
inline double Scalar_Quantizer::decode(int Index) const { return Levels(Index); }
inline double Scalar_Quantizer::Q(double x) const { return decode(encode(x)); }
inline double Scalar_Quantizer::operator()(double x) const { return Q(x); }
inline vec Scalar_Quantizer::operator()(const vec &x) const { return Q(x); }
inline void Scalar_Quantizer::set_levels(const vec &L) {Levels=L;sort(Levels); }
inline vec Scalar_Quantizer::get_levels() const {return Levels; }
//! ADD DOCUMENTATION HERE
int scalar_encode(double x, vec &Levels) ;
//! ADD DOCUMENTATION HERE
ivec scalar_encode(vec &x, vec &Levels);
//! ADD DOCUMENTATION HERE
inline double scalar_quantize(double x, vec &Levels) { return Levels(scalar_encode(x,Levels)); }
//! ADD DOCUMENTATION HERE
inline vec scalar_quantize(vec &x, vec &Levels) { return Levels(scalar_encode(x,Levels)); }
} // namespace itpp
#endif // #ifndef VQ_H
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