This abstract class represents a mathematical function that calculates a value of arbitrary type based on M real arguments. More...

Inheritance diagram for SimTK::Function_< T >:

Classes
class	Constant
	This is a Function_ subclass which simply returns a fixed value, independent of its arguments. More...

class	Linear
	This is a Function_ subclass whose output value is a linear function of its arguments: f(x, y, ...) = ax+by+...+c. More...

class	Polynomial
	This is a Function_ subclass whose output value is a polynomial of its argument: f(x) = ax^n+bx^(n-1)+...+c. More...

class	Sinusoid
	This is a Function_ subclass whose output value is a sinusoid of its argument: f(x) = asin(wx + p) where a is amplitude, w is frequency in radians per unit of x, p is phase in radians. More...

class	Step
	This is a Function_ subclass whose output value y=f(x) is smoothly stepped from y=y0 to y1 as its input argument goes from x=x0 to x1. More...

Public Member Functions
virtual	~Function_ ()

virtual T	calcValue (const Vector &x) const =0
	Calculate the value of this function at a particular point. More...

virtual T	calcDerivative (const Array_< int > &derivComponents, const Vector &x) const =0
	Calculate a partial derivative of this function at a particular point. More...

T	calcDerivative (const std::vector< int > &derivComponents, const Vector &x) const
	This provides compatibility with std::vector without requiring any copying. More...

virtual int	getArgumentSize () const =0
	Get the number of components expected in the input vector. More...

virtual int	getMaxDerivativeOrder () const =0
	Get the maximum derivative order this Function_ object can calculate. More...

Detailed Description

template<class T>
class SimTK::Function_< T >

This abstract class represents a mathematical function that calculates a value of arbitrary type based on M real arguments.

The output type is set as a template argument, while the number of input components may be determined at runtime. The name "Function" (with no trailing _) may be used as a synonym for Function_<Real>.

Subclasses define particular mathematical functions. Predefined subclasses are provided for several common function types: Function_<T>::Constant, Function_<T>::Linear, Function_<T>::Polynomial, and Function_<T>::Step. You can define your own subclasses for other function types. The Spline_ class also provides a convenient way to create various types of Functions.

Constructor & Destructor Documentation

template<class T>

virtual SimTK::Function_< T >::~Function_ ( )

inlinevirtual

Member Function Documentation

template<class T>

virtual T SimTK::Function_< T >::calcValue ( const Vector & x ) const

pure virtual

Calculate the value of this function at a particular point.

Parameters

x	the Vector of input arguments. Its size must equal the value returned by getArgumentSize().

Implemented in SimTK::BicubicFunction, SimTK::Function_< T >::Step, SimTK::Function_< T >::Sinusoid, SimTK::Function_< T >::Polynomial, SimTK::Function_< T >::Linear, SimTK::Spline_< T >, and SimTK::Function_< T >::Constant.

template<class T>

virtual T SimTK::Function_< T >::calcDerivative	(	const Array_< int > &	derivComponents,
		const Vector &	x
	)		const

pure virtual

Calculate a partial derivative of this function at a particular point.

Which derivative to take is specified by listing the input components with which to take it. For example, if derivComponents=={0}, that indicates a first derivative with respective to component 0. If derivComponents=={0, 0, 0}, that indicates a third derivative with respective to component 0. If derivComponents=={4, 7}, that indicates a partial second derivative with respect to components 4 and 7.

Parameters

derivComponents	The input components with respect to which the derivative should be taken. Its size must be less than or equal to the value returned by getMaxDerivativeOrder().
x	The Vector of input arguments. Its size must equal the value returned by getArgumentSize().