Description

B-Spline motion function.

#include <ChFunction_BSpline.h>

Inheritance diagram for chrono::ChFunction_BSpline:

Collaboration diagram for chrono::ChFunction_BSpline:

Public Member Functions
	ChFunction_BSpline (int p, const ChVectorDynamic<> &cpoints, ChVectorDynamic<> *knots=0)
	Generic univariate B-Spline of order p, approximating given control points. More...

	ChFunction_BSpline (int p, const ChVectorDynamic<> &x_interp, const ChVectorDynamic<> &y_dN_interp, const ChVectorDynamic< int > &der_order, ChVectorDynamic<> *knots=0)
	Univariate B-Spline of order p, exactly interpolating given waypoints and derivatives: internally solve linear problem A * b = c to find proper constrained control points (eg. More...

	ChFunction_BSpline (const ChFunction_BSpline &other)

virtual ChFunction_BSpline *	Clone () const override
	"Virtual" copy constructor (covariant return type).

virtual void	Setup_Data (int p, ChVectorDynamic<> cpoints, ChVectorDynamic<> *knots)
	Setup internal data of B-Spline.

virtual FunctionType	Get_Type () const override
	Get type of ChFunction.

int	Get_Order () const
	Get B-Spline order.

ChVectorDynamic	Get_Control_Points () const
	Get B-Spline control points.

ChVectorDynamic	Get_Knots () const
	Get B-Spline knots.

ChVectorDynamic	Get_Control_Points_Abscissae () const
	Get B-Spline averaged control points abscissae (Greville abscissae) as in [De Boor, chapt. More...

std::shared_ptr< geometry::ChBasisToolsBspline >	Get_Basis_Tool ()
	Get B-Spline internal tool to evaluate basis functions.

virtual double	Get_y (double x) const override
	B-Spline: y(x) = = SUM_i Ni,p(x) b_i.

virtual double	Get_y_dx (double x) const override
	B-Spline 1st derivative: y(x)' = = SUM_i Ni,p(x)' b_i.

virtual double	Get_y_dxdx (double x) const override
	B-Spline 2nd derivative: y(x)'' = = SUM_i Ni,p(x)'' b_i.

virtual double	Get_y_dxdxdx (double x) const override
	B-Spline 3rd derivative: y(x)''' = = SUM_i Ni,p(x)''' b_i.

virtual void	Recompute_Constrained (int p, const ChVectorDynamic<> &x_interp, const ChVectorDynamic<> &y_dN_interp, const ChVectorDynamic< int > der_order, ChVectorDynamic<> *knots=0)
	Recompute B-Spline control points to exactly interpolate given waypoints and derivatives (eg. More...

virtual void	ArchiveOut (ChArchiveOut &marchive) override
	Method to allow serialization of transient data to archives.

virtual void	ArchiveIn (ChArchiveIn &marchive) override
	Method to allow de-serialization of transient data from archives.

Public Member Functions inherited from chrono::ChFunction
	ChFunction (const ChFunction &other)

virtual double	Get_weight (double x) const
	Return the weight of the function (useful for applications where you need to mix different weighted ChFunctions)

virtual void	Estimate_x_range (double &xmin, double &xmax) const
	Return an estimate of the range of the function argument. More...

virtual void	Estimate_y_range (double xmin, double xmax, double &ymin, double &ymax, int derivate) const
	Return an estimate of the range of the function value. More...

virtual double	Get_y_dN (double x, int derivate) const
	Return the function derivative of specified order at the given point. More...

virtual void	Update (double x)
	Update could be implemented by children classes, ex. to launch callbacks.

virtual double	Compute_max (double xmin, double xmax, double sampling_step, int derivate) const
	Compute the maximum of y(x) in a range xmin-xmax, using a sampling method.

virtual double	Compute_min (double xmin, double xmax, double sampling_step, int derivate) const
	Compute the minimum of y(x) in a range xmin-xmax, using a sampling method.

virtual double	Compute_mean (double xmin, double xmax, double sampling_step, int derivate) const
	Compute the mean value of y(x) in a range xmin-xmax, using a sampling method.

virtual double	Compute_sqrmean (double xmin, double xmax, double sampling_step, int derivate) const
	Compute the square mean val. of y(x) in a range xmin-xmax, using sampling.

virtual double	Compute_int (double xmin, double xmax, double sampling_step, int derivate) const
	Compute the integral of y(x) in a range xmin-xmax, using a sampling method.

virtual double	Get_Ca_pos () const
	Computes the positive acceleration coefficient (inherited classes should customize this).

virtual double	Get_Ca_neg () const
	Compute the positive acceleration coefficient (inherited classes should customize this).

virtual double	Get_Cv () const
	Compute the speed coefficient (inherited classes must customize this).

virtual int	HandleNumber () const
	Return the number of handles of the function.

virtual bool	HandleAccess (int handle_id, double mx, double my, bool set_mode)
	Get the x and y position of handle, given identifier. More...

virtual int	FilePostscriptPlot (ChFile_ps *m_file, int plotY, int plotDY, int plotDDY)
	Plot function in graph space of the ChFile_ps postscript file where zoom factor, centering, color, thickness etc. More...

virtual int	FileAsciiPairsSave (ChStreamOutAscii &m_file, double xmin=0, double xmax=1, int msamples=200)
	Save function as X-Y pairs separated by space, with CR at each pair, into an ASCII file. More...

virtual void	EvaluateIntervaldN (ChMatrixDynamic<> &data, double xmin, double xmax, double step, int der=0)
	Sample function on entire interval, up to Nth derivative (der = 0: y, 1: y_dx, 2: y_dxdx, 3: y_dxdxdx). More...

Additional Inherited Members
Public Types inherited from chrono::ChFunction
enum	FunctionType { FUNCT_CUSTOM, FUNCT_CONST, FUNCT_CONSTACC, FUNCT_DERIVE, FUNCT_FILLET3, FUNCT_INTEGRATE, FUNCT_MATLAB, FUNCT_MIRROR, FUNCT_MOCAP, FUNCT_NOISE, FUNCT_OPERATION, FUNCT_OSCILLOSCOPE, FUNCT_POLY, FUNCT_POLY345, FUNCT_RAMP, FUNCT_RECORDER, FUNCT_REPEAT, FUNCT_SEQUENCE, FUNCT_SIGMA, FUNCT_SINE, FUNCT_LAMBDA, FUNCT_CYCLOIDAL, FUNCT_BSPLINE, FUNCT_DOUBLES }
	Enumeration of function types.

Constructor & Destructor Documentation

◆ ChFunction_BSpline() [1/2]

chrono::ChFunction_BSpline::ChFunction_BSpline	(	int	p,
		const ChVectorDynamic<> &	cpoints,
		ChVectorDynamic<> *	knots = `0`
	)

Generic univariate B-Spline of order p, approximating given control points.

If knot vector is not provided, initialize it as equally spaced and clamped at both ends.

Parameters

p	order
cpoints	control points
knots	knot vector

◆ ChFunction_BSpline() [2/2]

chrono::ChFunction_BSpline::ChFunction_BSpline	(	int	p,
		const ChVectorDynamic<> &	x_interp,
		const ChVectorDynamic<> &	y_dN_interp,
		const ChVectorDynamic< int > &	der_order,
		ChVectorDynamic<> *	knots = `0`
	)

Univariate B-Spline of order p, exactly interpolating given waypoints and derivatives: internally solve linear problem A * b = c to find proper constrained control points (eg.

useful to pass through given points with assigned velocities, at specific times). If knot vector is not provided, initialize it as equally spaced and clamped at both ends.

Parameters

p	order
x_interp	parameters (eg. times) at which perform interpolation
y_dN_interp	output value to interpolate, Nth derivative: y(x)^(Nth)
der_order	derivative order of given interpolation output (0: pos, 1: vel, 2: acc, ...)
knots	knot vector

Member Function Documentation

◆ Get_Control_Points_Abscissae()

ChVectorDynamic chrono::ChFunction_BSpline::Get_Control_Points_Abscissae ( ) const

Get B-Spline averaged control points abscissae (Greville abscissae) as in [De Boor, chapt.

XI] averaging formula. Useful, in univariate B-Spline functions, to get csi(x) abscissae associated to control points y(x), ie. b_i = [cpointx_i, cpointy_i] = [csi(x)_i, y(x)_i]

◆ Recompute_Constrained()

void chrono::ChFunction_BSpline::Recompute_Constrained	(	int	p,
		const ChVectorDynamic<> &	x_interp,
		const ChVectorDynamic<> &	y_dN_interp,
		const ChVectorDynamic< int >	der_order,
		ChVectorDynamic<> *	knots = `0`
	)

virtual

Recompute B-Spline control points to exactly interpolate given waypoints and derivatives (eg.

satisfy position, velocity, acceleration constraints)

Parameters

p	order
x_interp	parameters (eg. times) at which perform interpolation
y_dN_interp	output value to interpolate, Nth derivative: y(x)^(Nth)
der_order	derivative order of given interpolation output (0: pos, 1: vel, 2: acc, ...)
knots	knot vector

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

/builds/uwsbel/chrono/src/chrono/motion_functions/ChFunction_BSpline.h
/builds/uwsbel/chrono/src/chrono/motion_functions/ChFunction_BSpline.cpp

Description

Public Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ ChFunction_BSpline() [1/2]

◆ ChFunction_BSpline() [2/2]

Member Function Documentation

◆ Get_Control_Points_Abscissae()

◆ Recompute_Constrained()