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...

Inheritance diagram for SimTK::Function_< T >::Step:

Public Member Functions
	Step (const T &y0, const T &y1, Real x0, Real x1)
	Create a Function_::Step object that smoothly interpolates its output through a given range as its input moves through its range. More...

void	setParameters (const T &y0, const T &y1, Real x0, Real x1)
	Change the four parameters that define the step function; see constructor for documentation. More...

T	calcValue (const Vector &xin) const override
	Calculate the value of this function at a particular point. More...

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

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

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

Step *	clone () const override
	Create a new heap-allocated copy of this concrete Function. More...

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

Public Member Functions inherited from SimTK::Function_< T >
virtual	~Function_ ()

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

Detailed Description

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

This is an S-shaped function with first and second derivatives y'(x0)=y'(x1)=0 and y''(x0)=y''(x1)==0. The third derivative y''' exists and is continuous but we cannot guarantee anything about it at the end points.

Constructor & Destructor Documentation

◆ Step()

template<class T>

SimTK::Function_< T >::Step::Step	(	const T &	y0,
		const T &	y1,
		Real	x0,
		Real	x1
	)

inline

Create a Function_::Step object that smoothly interpolates its output through a given range as its input moves through its range.

Parameters

y0	Output value when (x-x0)*sign(x1-x0) <= 0.
y1	Output value when (x-x1)*sign(x1-x0) >= 0.
x0	Start of switching interval.
x1	End of switching interval (must not equal x0).

Template Parameters

T	The template type is the type of y0 and y1. This must be a type that supports subtraction and scalar multiplication by a Real so that we can compute an expression like y=y0 + f*(y1-y0) for some Real scalar f.

Note that the numerical values of x0 and x1 can be in either order x0 < x1 or x0 > x1, but they cannot be equal.

Member Function Documentation

◆ setParameters()

template<class T>

void SimTK::Function_< T >::Step::setParameters	(	const T &	y0,
		const T &	y1,
		Real	x0,
		Real	x1
	)

inline

Change the four parameters that define the step function; see constructor for documentation.

◆ calcValue()

template<class T>

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

inlineoverridevirtual

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().

Implements SimTK::Function_< T >.

◆ calcDerivative() [1/2]

template<class T>

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

inlineoverridevirtual

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().

Returns: The value of the selected derivative, which is of type T.

Implements SimTK::Function_< T >.

◆ getArgumentSize()

template<class T>

int SimTK::Function_< T >::Step::getArgumentSize ( ) const

inlineoverridevirtual

Get the number of components expected in the input vector.

Implements SimTK::Function_< T >.

◆ getMaxDerivativeOrder()

template<class T>

int SimTK::Function_< T >::Step::getMaxDerivativeOrder ( ) const

inlineoverridevirtual

Get the maximum derivative order this Function_ object can calculate.

Implements SimTK::Function_< T >.

◆ clone()

template<class T>

Step* SimTK::Function_< T >::Step::clone ( ) const

inlineoverridevirtual

Create a new heap-allocated copy of this concrete Function.

For backwards compatibility this is not pure virtual; it has a default implementation that throws an exception if called. However, it should always be implemented.

Reimplemented from SimTK::Function_< T >.

◆ calcDerivative() [2/2]

template<class T>

T SimTK::Function_< T >::Step::calcDerivative	(	const std::vector< int > &	derivComponents,
		const Vector &	x
	)		const

inline

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

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

Function.h

Public Member Functions

Detailed Description

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

Constructor & Destructor Documentation

◆ Step()

Member Function Documentation

◆ setParameters()

◆ calcValue()

◆ calcDerivative() [1/2]

◆ getArgumentSize()

◆ getMaxDerivativeOrder()

◆ clone()

◆ calcDerivative() [2/2]

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