Function_< T > Class Template Reference

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

#include <Function.h>

Inheritance diagram for Function_< T >:

List of all members.

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, . More...
class	Polynomial
	This is a Function_ subclass whose output value is a polynomial of its argument: f(x) = ax^n+bx^(n-1)+. 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.
virtual T	calcDerivative (const Array_< int > &derivComponents, const Vector &x) const =0
	Calculate a partial derivative of this function at a particular point.
T	calcDerivative (const std::vector< int > &derivComponents, const Vector &x) const
	This provides compatibility with std::vector without requiring any copying.
virtual int	getArgumentSize () const =0
	Get the number of components expected in the input vector.
virtual int	getMaxDerivativeOrder () const =0
	Get the maximum derivative order this Function_ object can calculate.

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

virtual ~Function_ ( ) [inline, virtual]

Member Function Documentation

T calcDerivative	(	const std::vector< int > &	derivComponents,
		const Vector &	x
	)			const `[inline]`

This provides compatibility with std::vector without requiring any copying.

Reimplemented in Spline_< T >, Constant, Linear, Polynomial, and Step.

References Function_< T >::calcDerivative().

Referenced by Function_< T >::calcDerivative().

virtual 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().