STK::ChebyshevCoefficients< Data, Coefs > Class Template Reference

ChebyshevCoefficients class allows to compute the coefficients of a sampled function using Chebyshev polynomials. More...

#include <STK_ChebyshevCoefficients.h>

Inheritance diagram for STK::ChebyshevCoefficients< Data, Coefs >:

Public Types
typedef IBasis< Data, Coefs >	Base
typedef Data::Type	Type
Public Types inherited from STK::IBasis< Data, Coefs >
typedef Data::Type	Type

Public Member Functions
	ChebyshevCoefficients (Data const *p_data=0, int dim=1, bool useDataValues=true)
	default constructor
	ChebyshevCoefficients (Data const &data, int dim, bool useDataValues=true)
	constructor
	ChebyshevCoefficients (ChebyshevCoefficients const &coefs)
	copy constructor.
virtual	~ChebyshevCoefficients ()
	Destructor.
ChebyshevCoefficients *	clone () const
	clone pattern implementation
virtual bool	run ()
	run the computations.
Public Member Functions inherited from STK::IBasis< Data, Coefs >
	IBasis ()
	default constructor
	IBasis (Data const *p_data, int dim, bool useDataValues=true)
	constructor
	IBasis (Data const &data, int dim, bool useDataValues=true)
	constructor
	IBasis (IBasis const &basis)
	copy constructor.
virtual	~IBasis ()
	destructor
int	dim () const
Coefs const &	coefficients () const
Type	minValue () const
Type	maxValue () const
void	setData (Data const &data)
	Set the data set.
void	setDim (int dim)
void	setMinValue (Type const &minValue)
void	setMaxValue (Type const &maxValue)
bool	initializeStep ()
	Initialize the parameters minValue_ and maxValue_ using data set.
Public Member Functions inherited from STK::IRunnerBase
String const &	error () const
	get the last error message.

Public Attributes
Data const *	p_data_
	the input data set
Coefs	coefficients_
	Array2D of the coefficients.
int	dim_
	number of dimension to build
Type	minValue_
	Minimal value of the data.
Type	maxValue_
	Maximal value of the data.

Additional Inherited Members
Protected Member Functions inherited from STK::IBasis< Data, Coefs >
virtual void	update ()
	update IBasis if a parameter or a new data set is set, update the state of this runner.
Protected Member Functions inherited from STK::IRunnerBase
	IRunnerBase ()
	default constructor
	IRunnerBase (IRunnerBase const &runner)
	copy constructor
virtual	~IRunnerBase ()
	destructor
Protected Attributes inherited from STK::IBasis< Data, Coefs >
Data const *	p_data_
	the input data set
int	dim_
	number of dimension to build
bool	useDataValues_
Type	minValue_
	Minimal value of the data.
Type	maxValue_
	Maximal value of the data.
Coefs	coefficients_
	Array2D of the coefficients.
Protected Attributes inherited from STK::IRunnerBase
String	msg_error_
	String with the last error message.
bool	hasRun_
	true if run has been used, false otherwise

Detailed Description

template<class Data, class Coefs = ArrayXX>
class STK::ChebyshevCoefficients< Data, Coefs >

ChebyshevCoefficients class allows to compute the coefficients of a sampled function using Chebyshev polynomials.

Chebyshev polynomials are important in approximation theory because the roots of the Chebyshev polynomials of the first kind, which are also called Chebyshev nodes, are used as nodes in polynomial interpolation.

Definition at line 51 of file STK_ChebyshevCoefficients.h.

Member Typedef Documentation

Base

template<class Data , class Coefs = ArrayXX>

typedef IBasis<Data, Coefs> STK::ChebyshevCoefficients< Data, Coefs >::Base

Definition at line 54 of file STK_ChebyshevCoefficients.h.

Type

template<class Data , class Coefs = ArrayXX>

typedef Data::Type STK::ChebyshevCoefficients< Data, Coefs >::Type

Definition at line 55 of file STK_ChebyshevCoefficients.h.

Constructor & Destructor Documentation

ChebyshevCoefficients() [1/3]

template<class Data , class Coefs = ArrayXX>

STK::ChebyshevCoefficients< Data, Coefs >::ChebyshevCoefficients ( Data const *  p_data = 0, int  dim = 1, bool  useDataValues = true  )

inline

default constructor

Parameters

p_data	pointer on the data set
dim	number of basis to use
useDataValues	if true use data in order to find the minValue_ and maxValue_, use values set otherwise

Definition at line 71 of file STK_ChebyshevCoefficients.h.

                         : Base(p_data, dim, useDataValues){}

ChebyshevCoefficients() [2/3]

template<class Data , class Coefs = ArrayXX>

STK::ChebyshevCoefficients< Data, Coefs >::ChebyshevCoefficients ( Data const &  data, int  dim, bool  useDataValues = true  )

inline

constructor

Parameters

data	reference on the data set
dim	number of basis to use
useDataValues	if true use data in order to find the minValue_ and maxValue_, use values set otherwise

Definition at line 79 of file STK_ChebyshevCoefficients.h.

                         : Base(data, dim, useDataValues){}

ChebyshevCoefficients() [3/3]

template<class Data , class Coefs = ArrayXX>

STK::ChebyshevCoefficients< Data, Coefs >::ChebyshevCoefficients ( ChebyshevCoefficients< Data, Coefs > const &  coefs )

inline

copy constructor.

Parameters

coefs

the coefficients to copy

Definition at line 84 of file STK_ChebyshevCoefficients.h.

: Base(coefs){}

~ChebyshevCoefficients()

template<class Data , class Coefs = ArrayXX>

virtual STK::ChebyshevCoefficients< Data, Coefs >::~ChebyshevCoefficients ( )

inlinevirtual

Destructor.

Definition at line 86 of file STK_ChebyshevCoefficients.h.

{}

Member Function Documentation

clone()

template<class Data , class Coefs = ArrayXX>

ChebyshevCoefficients * STK::ChebyshevCoefficients< Data, Coefs >::clone ( ) const

inline

clone pattern implementation

Definition at line 88 of file STK_ChebyshevCoefficients.h.

{ return new ChebyshevCoefficients(*this);}

run()

template<class Data , class Coefs >

bool STK::ChebyshevCoefficients< Data, Coefs >::run ( )

virtual

run the computations.

Implements STK::IRunnerBase.

Definition at line 95 of file STK_ChebyshevCoefficients.h.

{
  // check if data exists
  if (!p_data_)
  {
   msg_error_ = STKERROR_NO_ARG(Error in SinesCoefficients::run,p_data_ is null);
   return false;
  }
  if (!this->initializeStep()) return false;
  Data x = ( Type(2)* (*p_data_)-(minValue_+maxValue_))/(maxValue_-minValue_);
  // resize and initialize coefficients
  coefficients_.resize(p_data_->range(), Range(0, dim_)) =0;
  if (dim_>1)
  {
    coefficients_.col(0) = Type(1);
    if (dim_>2)
    {
      coefficients_.col(1) = x;
    }
    // compute T_{n+1}(x) = 2xT_n(x) - T_{n-1}(x)
    for(int j=2; j<coefficients_.endCols(); ++j)
    {
      coefficients_.col(j) = 2. * x *coefficients_.col(j-1) - coefficients_.col(j-2); ;
    }
  }
  // rescale
  for(int d=1; d<coefficients_.endCols(); ++d)
  {
    coefficients_.col(d) = (coefficients_.col(d) * (maxValue_-minValue_) + (minValue_+maxValue_))/Type(2);
  }
  this->hasRun_ = true;
  return true;
 
}

References STK::IRunnerBase::hasRun_, STK::IRegression< Array, Array, Weight >::initializeStep(), STK::IRunnerBase::msg_error_, STK::SinesCoefficients< Data, Coefs >::run(), and STKERROR_NO_ARG.

Member Data Documentation

coefficients_

template<class Data , class Coefs = ArrayXX>

Coefs STK::IBasis< Data, Coefs >::coefficients_

Array2D of the coefficients.

Definition at line 121 of file STK_IBasis.h.

dim_

template<class Data , class Coefs = ArrayXX>

int STK::IBasis< Data, Coefs >::dim_

number of dimension to build

Definition at line 112 of file STK_IBasis.h.

maxValue_

template<class Data , class Coefs = ArrayXX>

Type STK::IBasis< Data, Coefs >::maxValue_

Maximal value of the data.

Definition at line 118 of file STK_IBasis.h.

minValue_

template<class Data , class Coefs = ArrayXX>

Type STK::IBasis< Data, Coefs >::minValue_

Minimal value of the data.

Definition at line 116 of file STK_IBasis.h.

p_data_

template<class Data , class Coefs = ArrayXX>

Data const* STK::IBasis< Data, Coefs >::p_data_

the input data set

Definition at line 110 of file STK_IBasis.h.

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

• STK_ChebyshevCoefficients.h