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Isis 3.0 Developer's Reference (API) |
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Generic linear equation class. More...
#include <BasisFunction.h>
Inherited by Isis::Basis1VariableFunction, Isis::Parabola, and Isis::PolynomialBivariate.
Public Member Functions | |
| BasisFunction (const std::string &name, int numVars, int numCoefs) | |
| Creates a BasisFunction object. | |
| virtual | ~BasisFunction () |
| Destroys the BasisFunction object. | |
| void | SetCoefficients (const std::vector< double > &coefs) |
| Set the coefficients for the equation. | |
| double | Evaluate (const std::vector< double > &vars) |
| Compute the equation using the input variables. | |
| virtual void | Expand (const std::vector< double > &vars) |
| This is the function you should replace depending on your needs. | |
| int | Coefficients () const |
| Returns the number of coefficients for the equation. | |
| int | Variables () const |
| Returns the number of variables in the equation. | |
| std::string | Name () const |
| Returns the name of the equation. | |
| double | Term (int c) const |
| Returns the cth term. | |
| double | Coefficient (int i) const |
| Returns the ith coefficient. | |
Protected Attributes | |
| std::string | p_name |
| The name of the equation. Call it by using Name(). | |
| int | p_numVars |
| The number of variables in the equation. Call it by using Variables(). | |
| int | p_numCoefs |
| The number of coefficients in the equation. | |
| std::vector< double > | p_coefs |
| A vector of the coefficients in the equation. | |
| std::vector< double > | p_terms |
| A vector of the terms in the equation. | |
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:
![\[ x = C1*T1 + C2*T2 + ... + CN*TN; \]](form_16.png)
where C1-CN are coefficients and T1-TN are terms. Note that terms can be comprised of multiple variables and/or functions. For example,
![\[ x = C1 + C2*y + C3*y**2; \]](form_20.png)
![\[ x = C1 + C2*y + C3*z + C4*y*z; \]](form_21.png)
By deriving different functions off of this base class this allows the least squares class to be generalized.
| Isis::BasisFunction::BasisFunction | ( | const std::string & | name, | |
| int | numVars, | |||
| int | numCoefs | |||
| ) |
Creates a BasisFunction object.
| name | Name of the BasisFunction. For example, "affine". | |
| numVars | Number of variables in the equation. For example:
has two variables: y and z. | |
| numCoefs | Number of coefficients in the equation. For example:
has three coefficients: C1, C2 & C3. |
| virtual Isis::BasisFunction::~BasisFunction | ( | ) | [inline, virtual] |
Destroys the BasisFunction object.
| double Isis::BasisFunction::Coefficient | ( | int | i | ) | const [inline] |
Returns the ith coefficient.
| i | The index for the desired coefficient. |
References p_coefs.
Referenced by Isis::AutoReg::ModelSurface(), Isis::OverlapNormalization::Solve(), and Isis::Affine::Solve().
| int Isis::BasisFunction::Coefficients | ( | ) | const [inline] |
Returns the number of coefficients for the equation.
References p_numCoefs.
Referenced by Isis::OverlapNormalization::Solve().
| double Isis::BasisFunction::Evaluate | ( | const std::vector< double > & | vars | ) |
Compute the equation using the input variables.
| 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. |
Referenced by Isis::SpicePosition::SetEphemerisTimePolyFunction().
| 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,
![\[ x = C1 + C2*y + C3*z + C4*y*z \]](form_19.png)
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.
| vars | A vector of double values to use for the expansion. |
Reimplemented in Isis::Parabola, Isis::PolynomialBivariate, and Isis::PolynomialUnivariate.
| std::string Isis::BasisFunction::Name | ( | ) | const [inline] |
| void Isis::BasisFunction::SetCoefficients | ( | const std::vector< double > & | coefs | ) |
Set the coefficients for the equation.
| coefs | A vector of coefficients for the equation. |
Referenced by Isis::SpicePosition::SetEphemerisTimePolyFunction(), and Isis::SpicePosition::SetPolynomial().
| 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,
![\[ x = C1 + C2*x + C3*y + C4*x*y \]](form_22.png)
would return x*y for the 3rd term (zero-based)
| c | The index for the desired coefficient. |
References p_terms.
| int Isis::BasisFunction::Variables | ( | ) | const [inline] |
Returns the number of variables in the equation.
References p_numVars.
std::vector<double> Isis::BasisFunction::p_coefs [protected] |
A vector of the coefficients in the equation.
Call it by using Coefficient()
Referenced by Coefficient().
std::string Isis::BasisFunction::p_name [protected] |
int Isis::BasisFunction::p_numCoefs [protected] |
The number of coefficients in the equation.
Call it by using Coefficients()
Referenced by Coefficients().
int Isis::BasisFunction::p_numVars [protected] |
The number of variables in the equation. Call it by using Variables().
Referenced by Variables().
std::vector<double> Isis::BasisFunction::p_terms [protected] |
![\[ x = C1 + C2*y + C3*z \]](form_18.png)