Spline::PiecewisePolynomial Class Reference

#include <PiecewisePolynomial.h>

Public Types
typedef Polynomial< double >	Poly

Public Member Functions
	PiecewisePolynomial (const Poly &p, double a, double b)
	PiecewisePolynomial (const std::vector< Poly > &_segments, const std::vector< double > &_times, bool relative=false)
	PiecewisePolynomial (const std::vector< Poly > &_segments, const std::vector< double > &_times, const std::vector< double > &_timeShifts)
int	FindSegment (double t) const
double	Evaluate (double t) const
double	Derivative (double t) const
double	Derivative (double t, int n) const
double	operator() (double t) const
PiecewisePolynomial	Differentiate (int n=1) const
double	Start () const
double	End () const
double	StartTime () const
double	EndTime () const
void	Append (const Poly &p, double t, bool relative=false)
void	Concat (const PiecewisePolynomial &traj, bool relative=false)
void	TimeShift (double dt)
void	ZeroTimeShift ()
void	Split (double t, PiecewisePolynomial &front, PiecewisePolynomial &back) const
void	TrimFront (double tstart)
void	TrimBack (double tend)
PiecewisePolynomial	Select (double a, double b) const
std::pair< double, double >	MaxDiscontinuity (int derivative=0) const
bool	Read (File &f)
bool	Write (File &f) const
void	operator+= (double val)
void	operator-= (double val)
void	operator*= (double val)
void	operator/= (double val)
void	operator+= (const Polynomial< double > &b)
void	operator-= (const Polynomial< double > &b)
void	operator*= (const Polynomial< double > &b)

Public Attributes
std::vector< Poly >	segments
std::vector< double >	timeShift
std::vector< double >	times

Detailed Description

A trajectory y(t) consisting of a set of trajectory segments segments[], split among times times[]. segments[i] is defined over the interval Ii = [times[i],times[i+1]).

The timeShift member is defined to allow a difference between the segment's "local" time versus the "global" time of the overall polynomial. More precisely, over interval Ii, we define:

   y(t)=segments[i](t-timeShift[i])

And the segment's local time is defined over the domain [times[i]-timeShift[i],times[i+1]-timeShift[i]).

Member Function Documentation

void Spline::PiecewisePolynomial::Append	(	const Poly &	p,
		double	t,
		bool	relative = false
	)

Appends the segment to the trajectory following the final segment in the trajectory.

If relative is true, then T is interpreted as the total length of the segment, and segment(t) is defined on [0,T].

If relative is false, then T is interpreted as the final time of the segment, and segment(t) is defined on [self.endTime(),T]

void Spline::PiecewisePolynomial::Concat	(	const PiecewisePolynomial &	traj,
		bool	relative = false
	)

Appends traj to the current trajectory. If relative=true, the domain of traj is shifted forward in time by EndTime() before concatenating

References TimeShift().

Referenced by Split(), TrimBack(), and TrimFront().

std::pair< double, double > Spline::PiecewisePolynomial::MaxDiscontinuity

(

int

derivative = 0

)

const

Computes the maximum discontinuity of the i'th derivative. Return value is the time and absolute magnitude of the maximum discontinuity.

References ReadFile(), Split(), TimeShift(), TrimBack(), TrimFront(), and WriteFile().

PiecewisePolynomial Spline::PiecewisePolynomial::Select	(	double	a,
		double	b
	)		const

Selects a range

References TrimBack(), and TrimFront().

void Spline::PiecewisePolynomial::Split	(	double	t,
		PiecewisePolynomial &	front,
		PiecewisePolynomial &	back
	)		const

Splits the trajectory in two pieces

References Concat().

Referenced by MaxDiscontinuity().

void Spline::PiecewisePolynomial::TimeShift

(

double

dt

)

Moves time forward by dt

Referenced by Concat(), and MaxDiscontinuity().

void Spline::PiecewisePolynomial::TrimBack

(

double

tend

)

Sets a new end time tend

References Concat().

Referenced by MaxDiscontinuity(), and Select().

void Spline::PiecewisePolynomial::TrimFront

(

double

tstart

)

Sets a new start time tstart

References Concat().

Referenced by MaxDiscontinuity(), and Select().

void Spline::PiecewisePolynomial::ZeroTimeShift

(

)

Changes the local time domain of every segment to be defined with timeShift 0.

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

• PiecewisePolynomial.h
• PiecewisePolynomial.cpp