Isis::BasisFunction Class Reference

Generic linear equation class. More...

#include <BasisFunction.h>

Inheritance diagram for Isis::BasisFunction:

Collaboration diagram for Isis::BasisFunction:

Public Member Functions
	BasisFunction (const QString &name, int numVars, int numCoefs)
	Creates a BasisFunction object. More...
virtual	~BasisFunction ()
	Destroys the BasisFunction object. More...
void	SetCoefficients (const std::vector< double > &coefs)
	Set the coefficients for the equation. More...
double	Evaluate (const std::vector< double > &vars)
	Compute the equation using the input variables. More...
double	Evaluate (const double &var)
	Compute the equation using the input variable. More...
virtual void	Expand (const std::vector< double > &vars)
	This is the function you should replace depending on your needs. More...
int	Coefficients () const
	Returns the number of coefficients for the equation. More...
int	Variables () const
	Returns the number of variables in the equation. More...
QString	Name () const
	Returns the name of the equation. More...
double	Term (int c) const
	Returns the cth term. More...
double	Coefficient (int i) const
	Returns the ith coefficient. More...

Protected Attributes
QString	p_name
	The name of the equation. Call it by using Name() More...
int	p_numVars
	The number of variables in the equation. Call it by using Variables() More...
int	p_numCoefs
	The number of coefficients in the equation. More...
std::vector< double >	p_coefs
	A vector of the coefficients in the equation. More...
std::vector< double >	p_terms
	A vector of the terms in the equation. More...

Detailed Description

Generic linear equation class.

This is a base class for generating "generic" equations for the Isis least squares fitting algorithm (IsisLSQ). It allows the programmer to set up equations in the form of:

$$x = C1*T1 + C2*T2 + ... + CN*TN;$$

where C1-CN are coefficients and T1-TN are terms. Note that terms can be comprised of multiple variables and/or functions. For example,

$$x = C1 + C2*y + C3*y**2;$$

$$x = C1 + C2*y + C3*z + C4*y*z;$$

By deriving different functions off of this base class this allows the least squares class to be generalized.

Author

2004-06-24 Jeff Anderson

Todo:

Add coded example

History:

2005-03-16 Leah Dahmer - modified file to support Doxygen documentation.

History:

2015-02-20 Jeannie Backer - Improved error messages.

History:

2016-06-10 Marjorie Hahn - Added new signature for Evaluate() that only takes in a single value. Fixes #1679

Definition at line 48 of file BasisFunction.h.

Constructor & Destructor Documentation

BasisFunction()

Isis::BasisFunction::BasisFunction	(	const QString &	name,
		int	numVars,
		int	numCoefs
	)

Creates a BasisFunction object.

Parameters

name	Name of the BasisFunction. For example, "affine".
numVars	Number of variables in the equation. For example: $$x = C1 + C2*y + C3*z$$ has two variables: y and z.
numCoefs	Number of coefficients in the equation. For example: $$x = C1 + C2*y + C3*z$$ has three coefficients: C1, C2 & C3.

Definition at line 29 of file BasisFunction.cpp.

References p_name, p_numCoefs, and p_numVars.

~BasisFunction()

virtual Isis::BasisFunction::~BasisFunction ( )

inlinevirtual

Destroys the BasisFunction object.

Definition at line 52 of file BasisFunction.h.

Member Function Documentation

Coefficient()

double Isis::BasisFunction::Coefficient ( int  i ) const

inline

Returns the ith coefficient.

Parameters

i	The index for the desired coefficient.

Returns

The ith coefficient

Definition at line 107 of file BasisFunction.h.

References p_coefs.

Referenced by Isis::PolynomialUnivariate::DerivativeVar(), Isis::SpicePosition::LoadHermiteCache(), Isis::SurfaceModel::MinMax(), Isis::SpicePosition::SetPolynomial(), Isis::SpiceRotation::SetPolynomial(), and Isis::Affine::Solve().

Coefficients()

int Isis::BasisFunction::Coefficients ( ) const

inline

Returns the number of coefficients for the equation.

Returns

The number of coefficients.

Definition at line 64 of file BasisFunction.h.

References p_numCoefs.

Referenced by Isis::PolynomialUnivariate::DerivativeCoef(), Isis::PolynomialUnivariate::DerivativeVar(), Isis::SpicePosition::SetPolynomial(), Isis::SpiceRotation::SetPolynomial(), Isis::LeastSquares::SolveQRD(), and Isis::LeastSquares::SolveSVD().

Evaluate() [1/2]

double Isis::BasisFunction::Evaluate

(

const double &

var

)

Compute the equation using the input variable.

Parameters

var	A single double value to use for the equation.

Returns

The output double value resulting from the equation.

Definition at line 101 of file BasisFunction.cpp.

References Evaluate().

Evaluate() [2/2]

double Isis::BasisFunction::Evaluate

(

const std::vector< double > &

vars

)

Compute the equation using the input variables.

Parameters

vars	A vector of double values to use for the equation. After setting the coefficients, this can be invoked many times to compute output values given input values.

Returns

The output value.

Definition at line 64 of file BasisFunction.cpp.

References Expand(), p_coefs, p_numCoefs, p_numVars, p_terms, Isis::IException::Programmer, and Isis::toString().

Referenced by Evaluate(), Isis::LeastSquares::Evaluate(), Isis::SpiceRotation::EvaluatePolyFunction(), Isis::SpicePosition::LoadHermiteCache(), Isis::SpicePosition::SetEphemerisTimePolyFunction(), Isis::SpiceRotation::setEphemerisTimePolyFunction(), Isis::LeastSquares::SolveQRD(), and Isis::LeastSquares::SolveSVD().

Expand()

void Isis::BasisFunction::Expand ( const std::vector< double > &  vars )

virtual

This is the function you should replace depending on your needs.

It will expand the variables into the terms of the equation. For example,

$$x = C1 + C2*y + C3*z + C4*y*z$$

must be expanded into the p_terms vector as (1.0, y, z, y*z). Note that the term expansion is not limited, you can use cos, sin, sqrt, abs, etc. This virtual method is automatically invoked by the Evaluate method. We provide a default expansion of p_terms = vars, just a linear combination of the variables.

Parameters

vars	A vector of double values to use for the expansion.

Reimplemented in Isis::PolynomialUnivariate, Isis::PolynomialBivariate, and Isis::NthOrderPolynomial.

Definition at line 123 of file BasisFunction.cpp.

References p_terms.

Referenced by Evaluate(), Isis::LeastSquares::FillSparseA(), Isis::LeastSquares::SolveQRD(), and Isis::LeastSquares::SolveSVD().

Name()

QString Isis::BasisFunction::Name ( ) const

inline

Returns the name of the equation.

Returns

The name of the equation.

Definition at line 80 of file BasisFunction.h.

References p_name.

Referenced by Isis::LeastSquares::AddKnown().

SetCoefficients()

void Isis::BasisFunction::SetCoefficients

(

const std::vector< double > &

coefs

)

Set the coefficients for the equation.

Parameters

coefs

A vector of coefficients for the equation.

Definition at line 42 of file BasisFunction.cpp.

References p_coefs, p_numCoefs, Isis::IException::Programmer, and Isis::toString().

Referenced by Isis::SpiceRotation::DCJdt(), Isis::SpiceRotation::EvaluatePolyFunction(), Isis::SpicePosition::LoadHermiteCache(), Isis::PolynomialUnivariate::PolynomialUnivariate(), Isis::SpicePosition::SetEphemerisTimePolyFunction(), Isis::SpiceRotation::setEphemerisTimePolyFunction(), Isis::SpiceRotation::SetPolynomial(), Isis::SpicePosition::SetPolynomial(), Isis::LeastSquares::SolveQRD(), Isis::LeastSquares::SolveSparse(), and Isis::LeastSquares::SolveSVD().

Term()

double Isis::BasisFunction::Term ( int  c ) const

inline

Returns the cth term.

This is only valid after a Evalute/Expand has been invoked. It represents the expansion of the variables into the ith term. For example,

$$x = C1 + C2*x + C3*y + C4*x*y$$

would return x*y for the 3rd term (zero-based)

Parameters

c	The index for the desired coefficient.

Returns

The cth term.

Definition at line 97 of file BasisFunction.h.

References p_terms.

Referenced by Isis::LeastSquares::FillSparseA(), Isis::LeastSquares::SolveQRD(), and Isis::LeastSquares::SolveSVD().

Variables()

int Isis::BasisFunction::Variables ( ) const

inline

Returns the number of variables in the equation.

Returns

The number of variables.

Definition at line 72 of file BasisFunction.h.

References p_numVars.

Referenced by Isis::LeastSquares::AddKnown(), and Isis::NthOrderPolynomial::Expand().

Member Data Documentation

p_coefs

std::vector<double> Isis::BasisFunction::p_coefs

protected

A vector of the coefficients in the equation.

Call it by using Coefficient()

Definition at line 123 of file BasisFunction.h.

Referenced by Coefficient(), Evaluate(), and SetCoefficients().

p_name

QString Isis::BasisFunction::p_name

protected

The name of the equation. Call it by using Name()

Definition at line 113 of file BasisFunction.h.

Referenced by BasisFunction(), and Name().

p_numCoefs

int Isis::BasisFunction::p_numCoefs

protected

The number of coefficients in the equation.

Call it by using Coefficients()

Definition at line 119 of file BasisFunction.h.

Referenced by BasisFunction(), Coefficients(), Evaluate(), and SetCoefficients().

p_numVars

int Isis::BasisFunction::p_numVars

protected

The number of variables in the equation. Call it by using Variables()

Definition at line 115 of file BasisFunction.h.

Referenced by BasisFunction(), Evaluate(), and Variables().

p_terms

std::vector<double> Isis::BasisFunction::p_terms

protected

A vector of the terms in the equation.

Call it by using Term()

Definition at line 127 of file BasisFunction.h.

Referenced by Evaluate(), Expand(), Isis::NthOrderPolynomial::Expand(), Isis::PolynomialBivariate::Expand(), Isis::PolynomialUnivariate::Expand(), and Term().

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

• src/base/objs/BasisFunction/BasisFunction.h
• src/base/objs/BasisFunction/BasisFunction.cpp