Standard RK4 integrator. More...

#include <crocoddyl/core/integrator/rk4.hpp>

Public Types
typedef ActionDataAbstractTpl< Scalar >	ActionDataAbstract

typedef IntegratedActionModelAbstractTpl< Scalar >	Base

typedef ControlParametrizationModelAbstractTpl< Scalar >	ControlParametrizationModelAbstract

typedef IntegratedActionDataRK4Tpl< Scalar >	Data

typedef DifferentialActionModelAbstractTpl< Scalar >	DifferentialActionModelAbstract

typedef MathBaseTpl< Scalar >	MathBase

typedef MathBase::MatrixXs	MatrixXs

typedef MathBase::VectorXs	VectorXs

Public Member Functions
	IntegratedActionModelRK4Tpl (boost::shared_ptr< DifferentialActionModelAbstract > model, const Scalar time_step=Scalar(1e-3), const bool with_cost_residual=true)

virtual void	calc (const boost::shared_ptr< ActionDataAbstract > &data, const Eigen::Ref< const VectorXs > &x)
	Integrate the total cost value for nodes that depends only on the state using RK4 scheme. More...

virtual void	calc (const boost::shared_ptr< ActionDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)
	Integrate the differential action model using RK4 scheme. More...

virtual void	calcDiff (const boost::shared_ptr< ActionDataAbstract > &data, const Eigen::Ref< const VectorXs > &x)
	Compute the partial derivatives of the cost. More...

virtual void	calcDiff (const boost::shared_ptr< ActionDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)
	Compute the partial derivatives of the RK4 integrator. More...

virtual bool	checkData (const boost::shared_ptr< ActionDataAbstract > &data)
	Checks that a specific data belongs to this model.

virtual boost::shared_ptr< ActionDataAbstract >	createData ()
	Create the RK4 integrator data. More...

	DEPRECATED ("Use IntegratedActionModelRK", IntegratedActionModelRK4Tpl(boost::shared_ptr< DifferentialActionModelAbstract > model, boost::shared_ptr< ControlParametrizationModelAbstract > control, const Scalar time_step=Scalar(1e-3), const bool with_cost_residual=true);) DEPRECATED("Use IntegratedActionModelRK"
	Initialize the RK4 integrator. More...

virtual void	print (std::ostream &os) const
	Print relevant information of the RK4 integrator model. More...

virtual void	quasiStatic (const boost::shared_ptr< ActionDataAbstract > &data, Eigen::Ref< VectorXs > u, const Eigen::Ref< const VectorXs > &x, const std::size_t maxiter=100, const Scalar tol=Scalar(1e-9))
	Computes the quasic static commands. More...

Public Attributes
EIGEN_MAKE_ALIGNED_OPERATOR_NEW typedef _Scalar	Scalar

Protected Attributes
boost::shared_ptr< ControlParametrizationModelAbstract >	control_
	Model of the control parametrization.

boost::shared_ptr< DifferentialActionModelAbstract >	differential_
	< Control parametrization

std::size_t	nu_
	< Differential action model

boost::shared_ptr< StateAbstract >	state_
	< Dimension of the control

Scalar	time_step2_
	< Model of the state

Scalar	time_step_
	< Square of the time step used for integration

bool	with_cost_residual_
	< Time step used for integration

Detailed Description

template<typename _Scalar>
class crocoddyl::IntegratedActionModelRK4Tpl< _Scalar >

Standard RK4 integrator.

It applies a standard RK4 integration scheme to a differential (i.e., continuous time) action model.

This standard RK4 scheme introduces also the possibility to parametrize the control trajectory inside an integration step, for instance using polynomials. This requires introducing some notation to clarify the difference between the control inputs of the differential model and the control inputs to the integrated model. We have decided to use \(\mathbf{w}\) to refer to the control inputs of the differential model and \(\mathbf{u}\) for the control inputs of the integrated action model.

See also: IntegratedActionModelAbstractTpl, calc(), calcDiff(), createData()

Definition at line 70 of file fwd.hpp.

Member Function Documentation

◆ DEPRECATED()

DEPRECATED	(	"Use IntegratedActionModelRK"	,
		IntegratedActionModelRK4Tpl< _Scalar >(boost::shared_ptr< DifferentialActionModelAbstract > model, boost::shared_ptr< ControlParametrizationModelAbstract > control, const Scalar time_step=Scalar(1e-3), const bool with_cost_residual=true);
	)

Initialize the RK4 integrator.

Parameters

[in]	model	Differential action model
[in]	control	Control parametrization
[in]	time_step	Step time (default 1e-3)
[in]	with_cost_residual	Compute cost residual (default true)

Initialize the RK4 integrator

This initialization uses ControlParametrizationPolyZeroTpl for the control parametrization.

Parameters

[in]	model	Differential action model
[in]	time_step	Step time (default 1e-3)
[in]	with_cost_residual	Compute cost residual (default true)

◆ calc() [1/2]

virtual void calc	(	const boost::shared_ptr< ActionDataAbstract > &	data,
		const Eigen::Ref< const VectorXs > &	x,
		const Eigen::Ref< const VectorXs > &	u
	)

virtual

Integrate the differential action model using RK4 scheme.

Parameters

[in]	data	RK4 integrator data
[in]	x	State point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]	u	Control input \(\mathbf{u}\in\mathbb{R}^{nu}\)

◆ calc() [2/2]

virtual void calc	(	const boost::shared_ptr< ActionDataAbstract > &	data,
		const Eigen::Ref< const VectorXs > &	x
	)

virtual

Integrate the total cost value for nodes that depends only on the state using RK4 scheme.

It computes the total cost and defines the next state as the current one. This function is used in the terminal nodes of an optimal control problem.

Parameters

[in]	data	RK4 integrator data
[in]	x	State point \(\mathbf{x}\in\mathbb{R}^{ndx}\)

◆ calcDiff() [1/2]

virtual void calcDiff	(	const boost::shared_ptr< ActionDataAbstract > &	data,
		const Eigen::Ref< const VectorXs > &	x,
		const Eigen::Ref< const VectorXs > &	u
	)

virtual

Compute the partial derivatives of the RK4 integrator.

Parameters

[in]	data	RK4 integrator data
[in]	x	State point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]	u	Control input \(\mathbf{u}\in\mathbb{R}^{nu}\)

◆ calcDiff() [2/2]

virtual void calcDiff	(	const boost::shared_ptr< ActionDataAbstract > &	data,
		const Eigen::Ref< const VectorXs > &	x
	)

virtual

Compute the partial derivatives of the cost.

It updates the derivatives of the cost function with respect to the state only. This function is used in the terminal nodes of an optimal control problem.

Parameters

[in]	data	RK4 integrator data
[in]	x	State point \(\mathbf{x}\in\mathbb{R}^{ndx}\)

◆ createData()

virtual boost::shared_ptr<ActionDataAbstract> createData ( )

virtual

Create the RK4 integrator data.

Returns: the RK4 integrator data

◆ quasiStatic()

virtual void quasiStatic	(	const boost::shared_ptr< ActionDataAbstract > &	data,
		Eigen::Ref< VectorXs >	u,
		const Eigen::Ref< const VectorXs > &	x,
		const std::size_t	maxiter = `100`,
		const Scalar	tol = `Scalar(1e-9)`
	)

virtual

Computes the quasic static commands.

The quasic static commands are the ones produced for a the reference posture as an equilibrium point, i.e. for \(\mathbf{f^q_x}\delta\mathbf{q}+\mathbf{f_u}\delta\mathbf{u}=\mathbf{0}\)

Parameters

[in]	data	RK4 integrator data
[out]	u	Quasic static commands
[in]	x	State point (velocity has to be zero)
[in]	maxiter	Maximum allowed number of iterations
[in]	tol	Tolerance

◆ print()

virtual void print ( std::ostream & os ) const

virtual

Print relevant information of the RK4 integrator model.

Parameters

[out] os Output stream object

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

include/crocoddyl/core/fwd.hpp
include/crocoddyl/core/integrator/rk4.hpp

Public Types

Public Member Functions

Public Attributes

Protected Attributes

Detailed Description

template<typename _Scalar> class crocoddyl::IntegratedActionModelRK4Tpl< _Scalar >

Member Function Documentation

◆ DEPRECATED()

◆ calc() [1/2]

◆ calc() [2/2]

◆ calcDiff() [1/2]

◆ calcDiff() [2/2]

◆ createData()

◆ quasiStatic()

◆ print()

template<typename _Scalar>
class crocoddyl::IntegratedActionModelRK4Tpl< _Scalar >