fr.cnes.sirius.patrius.math.parameter

Class LinearCombinationFunction

java.lang.Object

fr.cnes.sirius.patrius.math.parameter.LinearCombinationFunction

All Implemented Interfaces:

IParamDiffFunction, IParameterizable, IParameterizableFunction, Serializable

Direct Known Subclasses:

ConstantFunction, LinearFunction, NthOrderPolynomialFunction

public class LinearCombinationFunction
extends Object
implements IParamDiffFunction

This class is used to define a linear combination of functions where the linear coefficients are parameters:
g(sc) = p1*f1(sc) + p2*f2(sc) + ...

Note: The child class have to cast their functions to Serializable if it should be serializable (not required).

Author:

veuillezh, bonitt

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<Parameter,Function<SpacecraftState,Double>>	functions Map describing the functions.
protected static String	PARAMETER_PREFIX_NAME Standard parameter prefix name: "A".

Constructor Summary

Constructors

Constructor and Description
LinearCombinationFunction(Collection<Function<SpacecraftState,Double>> monomialFunctionCollection) Constructor to initialize the function with the monomial function description.
LinearCombinationFunction(Map<Parameter,Function<SpacecraftState,Double>> functions) Constructor to initialize the function.

Method Summary

Modifier and Type	Method and Description
double	derivativeValue(Parameter p, SpacecraftState s) Compute the derivative value with respect to the input parameter.
ArrayList<Parameter>	getParameters() Get the supported parameters.
boolean	isDifferentiableBy(Parameter p) Tell if the function is differentiable by the given parameter.
boolean	supportsParameter(Parameter param) Check if a parameter is supported.
double	value(SpacecraftState state) Getting the value of the function.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PARAMETER_PREFIX_NAME

protected static final String PARAMETER_PREFIX_NAME

Standard parameter prefix name: "A".

See Also:

Constant Field Values

functions

protected final Map<Parameter,Function<SpacecraftState,Double>> functions

Map describing the functions.

Constructor Detail

LinearCombinationFunction

public LinearCombinationFunction(Map<Parameter,Function<SpacecraftState,Double>> functions)

Constructor to initialize the function.

WARNING: The given map is directly stored in the function. Please be careful to not modify the map, otherwise the function would change to, which can lead to unexpected behaviors.

Parameters:

functions - Map describing the functions

Throws:

NullArgumentException - if a parameter (key) or a monomial function (value) is described by null because a null parameter/function can't be applied

LinearCombinationFunction

public LinearCombinationFunction(Collection<Function<SpacecraftState,Double>> monomialFunctionCollection)

Constructor to initialize the function with the monomial function description. The parameters are automatically initialized with a generic name and a 0.0 value.

Parameters:

monomialFunctionCollection - Collection describing the monomial functions

Throws:

NullArgumentException - if a monomial function is described by null because a null function can't be applied

Method Detail

derivativeValue

public double derivativeValue(Parameter p,
                              SpacecraftState s)

Compute the derivative value with respect to the input parameter.

Specified by:

derivativeValue in interface IParamDiffFunction

Parameters:

p - parameter

s - current state

Returns:

the derivative value

value

public double value(SpacecraftState state)

Getting the value of the function.

Specified by:

value in interface IParameterizableFunction

Parameters:

state - the spacecraft state

Returns:

the value of the function.

supportsParameter

public boolean supportsParameter(Parameter param)

Check if a parameter is supported.

Specified by:

supportsParameter in interface IParameterizable

Parameters:

param - parameter to check

Returns:

true if the parameter is supported

isDifferentiableBy

public boolean isDifferentiableBy(Parameter p)

Tell if the function is differentiable by the given parameter.

Specified by:

isDifferentiableBy in interface IParamDiffFunction

Parameters:

p - function parameter

Returns:

true if the function is differentiable by the given parameter.

getParameters

public ArrayList<Parameter> getParameters()

Get the supported parameters.

The list is returned in a shallow copy.

Specified by:

getParameters in interface IParameterizable

Returns:

list of supported parameters