Description

Sequence function: y = sequence_of_functions(f1(y), f2(y), f3(y)) All other function types can be inserted into this.

This function is very important because very complex motion laws can be created by sequencing many basic ChFunctions.

#include <ChFunction_Sequence.h>

Inheritance diagram for chrono::ChFunction_Sequence:

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Collaboration diagram for chrono::ChFunction_Sequence:

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Public Member Functions
	ChFunction_Sequence (const ChFunction_Sequence &other)

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

virtual FunctionType	Get_Type () const override
	Return the unique function type identifier.

virtual double	Get_y (double x) const override
	Return the y value of the function, at position x.

virtual double	Get_y_dx (double x) const override
	Return the dy/dx derivative of the function, at position x. More...

virtual double	Get_y_dxdx (double x) const override
	Return the ddy/dxdx double derivative of the function, at position x. More...

void	Set_start (double m_start)
	The sequence of functions starts at this x value.

double	Get_start () const

std::list< ChFseqNode > &	Get_list ()
	Access the list of the sub-functions.

void	Setup ()
	Scans all the seq.of functions and setup the timings and continuity offsets, to satisfy all constraints. More...

bool	InsertFunct (std::shared_ptr< ChFunction > myfx, double duration, double weight=1, bool c0=false, bool c1=false, bool c2=false, int position=-1)
	Insert function after the fx with defined "position" index in list. More...

bool	KillFunct (int position)
	Remove and deletes function with defined "position", and returns true. More...

std::shared_ptr< ChFunction >	GetNthFunction (int position)
	Returns the ChFunction with given "position". More...

ChFseqNode *	GetNthNode (int position)
	As above, but returns the function node (containing function pointer, function duration, continuity flags with previous node, etc.)

double	GetNthDuration (int position)
	As above, but returning duration. More...

virtual double	Get_weight (double x) const override
	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 override
	Return an estimate of the range of the function argument. More...

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

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

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 }
	Enumeration of function types.

Member Function Documentation

◆ Estimate_x_range()

void chrono::ChFunction_Sequence::Estimate_x_range	(	double &	xmin,
		double &	xmax
	)		const

overridevirtual

Return an estimate of the range of the function argument.

(Can be used for automatic zooming in a GUI)

Reimplemented from chrono::ChFunction.

◆ Get_y_dx()

double chrono::ChFunction_Sequence::Get_y_dx ( double x ) const

overridevirtual

Return the dy/dx derivative of the function, at position x.

Note that inherited classes may also avoid overriding this method, because this base method already provide a general-purpose numerical differentiation to get dy/dx only from the Get_y() function. (however, if the analytical derivative is known, it may better to implement a custom method).

Reimplemented from chrono::ChFunction.

◆ Get_y_dxdx()

double chrono::ChFunction_Sequence::Get_y_dxdx ( double x ) const

overridevirtual

Return the ddy/dxdx double derivative of the function, at position x.

Note that inherited classes may also avoid overriding this method, because this base method already provide a general-purpose numerical differentiation to get ddy/dxdx only from the Get_y() function. (however, if the analytical derivative is known, it may be better to implement a custom method).

Reimplemented from chrono::ChFunction.

◆ GetNthDuration()

double chrono::ChFunction_Sequence::GetNthDuration ( int position )

As above, but returning duration.

(return value is reference, so it can be also changed later, but remember Setup() for the ChFunction_Sequence after you modified this return value by reference TO DO). If no function, returns 0.

◆ GetNthFunction()

std::shared_ptr< ChFunction > chrono::ChFunction_Sequence::GetNthFunction ( int position )

Returns the ChFunction with given "position".

If position = 0, returns always head (beginning),
If position = -1 returns tail (end).
If position > max number of current nodes, returns tail fx anyway.

◆ HandleAccess()

bool chrono::ChFunction_Sequence::HandleAccess	(	int	handle_id,
		double	mx,
		double	my,
		bool	set_mode
	)

overridevirtual

Get the x and y position of handle, given identifier.

If set mode, x and y values are stored. Return false if handle not found.

Reimplemented from chrono::ChFunction.

◆ InsertFunct()

bool chrono::ChFunction_Sequence::InsertFunct	(	std::shared_ptr< ChFunction >	myfx,
		double	duration,
		double	weight = `1`,
		bool	c0 = `false`,
		bool	c1 = `false`,
		bool	c2 = `false`,
		int	position = `-1`
	)

Insert function after the fx with defined "position" index in list.

If index is higher than available objects, it simply goes to the end.
If index = 0 insert at the beginning,
If index = -1 insert at the end. Inserted functions will be deleted automatically when this object will be deleted. The fx segment has its own 'weight': use 1.0 for default, or different weights if you want that Get_weight() will give different results depending on the "x" parameter. Set c0=true if you want to force C0 continuity with previous function (an offset will be implicitly added to the function, as y=f(x)+Offset). Same for C1 and C2 continuity, using c1 and c2 flags.

Parameters

myfx	the function to insert
duration	duration of the time segment for this function
weight	optional weight scalar
c0	impose continuity to previous f() by offsetting/slanting
c1	impose continuity to previous f() by offsetting/slanting
c2	impose continuity to previous f() by offsetting/slanting
position	position index, 0,1,2,3.. (if -1 insert at the end)

◆ KillFunct()

bool chrono::ChFunction_Sequence::KillFunct ( int position )

Remove and deletes function with defined "position", and returns true.

If position = 0, removes always head (beginning),
If position = -1 removes tail (end).
If position > max number of current nodes, removes tail anyway, but returns false.

◆ Setup()

void chrono::ChFunction_Sequence::Setup ( )

Scans all the seq.of functions and setup the timings and continuity offsets, to satisfy all constraints.

This must be called whenever a new function is inserted, or its timing and continuity constraints are changed.

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

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

Description

Public Member Functions

Additional Inherited Members

Member Function Documentation

◆ Estimate_x_range()

◆ Get_y_dx()

◆ Get_y_dxdx()

◆ GetNthDuration()

◆ GetNthFunction()

◆ HandleAccess()

◆ InsertFunct()

◆ KillFunct()

◆ Setup()