crocoddyl  1.7.0
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CostModelAbstractTpl< _Scalar > Class Template Referenceabstract

Abstract class for cost models. More...

#include <crocoddyl/core/cost-base.hpp>

Inheritance diagram for CostModelAbstractTpl< _Scalar >:

Public Types

typedef ActivationModelAbstractTpl< Scalar > ActivationModelAbstract
 
typedef ActivationModelQuadTpl< Scalar > ActivationModelQuad
 
typedef CostDataAbstractTpl< Scalar > CostDataAbstract
 
typedef DataCollectorAbstractTpl< Scalar > DataCollectorAbstract
 
typedef MathBaseTpl< Scalar > MathBase
 
typedef MathBase::MatrixXs MatrixXs
 
typedef StateAbstractTpl< Scalar > StateAbstract
 
typedef MathBase::VectorXs VectorXs
 

Public Member Functions

 CostModelAbstractTpl (boost::shared_ptr< StateAbstract > state, boost::shared_ptr< ActivationModelAbstract > activation, const std::size_t nu)
 Initialize the cost model. More...
 
 CostModelAbstractTpl (boost::shared_ptr< StateAbstract > state, boost::shared_ptr< ActivationModelAbstract > activation)
 
 CostModelAbstractTpl (boost::shared_ptr< StateAbstract > state, const std::size_t nr, const std::size_t nu)
 
 CostModelAbstractTpl (boost::shared_ptr< StateAbstract > state, const std::size_t nr)
 
virtual void calc (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)=0
 Compute the cost value and its residual vector. More...
 
void calc (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x)
 
virtual void calcDiff (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)=0
 Compute the Jacobian and Hessian of cost and its residual vector. More...
 
void calcDiff (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x)
 
virtual boost::shared_ptr< CostDataAbstractcreateData (DataCollectorAbstract *const data)
 Create the cost data. More...
 
const boost::shared_ptr< ActivationModelAbstract > & get_activation () const
 Return the activation model.
 
std::size_t get_nu () const
 Return the dimension of the control input.
 
template<class ReferenceType >
ReferenceType get_reference () const
 Return the cost reference.
 
const boost::shared_ptr< StateAbstract > & get_state () const
 Return the state.
 
template<class ReferenceType >
void set_reference (ReferenceType ref)
 Modify the cost reference.
 

Public Attributes

EIGEN_MAKE_ALIGNED_OPERATOR_NEW typedef _Scalar Scalar
 

Protected Member Functions

virtual void get_referenceImpl (const std::type_info &, void *) const
 
virtual void set_referenceImpl (const std::type_info &, const void *)
 

Protected Attributes

boost::shared_ptr< ActivationModelAbstractactivation_
 Activation model.
 
std::size_t nu_
 Control dimension.
 
boost::shared_ptr< StateAbstractstate_
 State description.
 
VectorXs unone_
 No control vector.
 

Detailed Description

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

Abstract class for cost models.

In Crocoddyl, a cost model is defined by the scalar activation function \(a(\cdot)\) and by the residual function \(\mathbf{r}(\cdot)\) as follows:

\[ cost = a(\mathbf{r}(\mathbf{x}, \mathbf{u})), \]

where the residual function depends on the state point \(\mathbf{x}\in\mathcal{X}\), which lies in the state manifold described with a nq-tuple, its velocity \(\dot{\mathbf{x}}\in T_{\mathbf{x}}\mathcal{X}\) that belongs to the tangent space with nv dimension, and the control input \(\mathbf{u}\in\mathbb{R}^{nu}\). The residual vector is defined by \(\mathbf{r}\in\mathbb{R}^{nr}\) where nr describes its dimension in the Euclidean space. On the other hand, the activation function builds a cost value based on the definition of the residual vector. The residual vector has to be specialized in a derived classes.

The main computations are carring out in calc and calcDiff routines. calc computes the cost (and its residual) and calcDiff computes the derivatives of the cost function (and its residual). Concretely speaking, calcDiff builds a linear-quadratic approximation of the cost function with the form: \(\mathbf{l_x}\in\mathbb{R}^{ndx}\), \(\mathbf{l_u}\in\mathbb{R}^{nu}\), \(\mathbf{l_{xx}}\in\mathbb{R}^{ndx\times ndx}\), \(\mathbf{l_{xu}}\in\mathbb{R}^{ndx\times nu}\), \(\mathbf{l_{uu}}\in\mathbb{R}^{nu\times nu}\) are the Jacobians and Hessians, respectively. Additionally, it is important remark that calcDiff() computes the derivates using the latest stored values by calc(). Thus, we need to run first calc().

See also
StateAbstractTpl, ActivationModelAbstractTpl, calc(), calcDiff(), createData()

Definition at line 47 of file cost-base.hpp.

Constructor & Destructor Documentation

◆ CostModelAbstractTpl() [1/4]

CostModelAbstractTpl ( boost::shared_ptr< StateAbstract state,
boost::shared_ptr< ActivationModelAbstract activation,
const std::size_t  nu 
)

Initialize the cost model.

Parameters
[in]stateState of the multibody system
[in]activationActivation model
[in]nuDimension of control vector

◆ CostModelAbstractTpl() [2/4]

CostModelAbstractTpl ( boost::shared_ptr< StateAbstract state,
boost::shared_ptr< ActivationModelAbstract activation 
)

Initialize the cost model.

The default nu value is obtained from StateAbstractTpl::get_nv().

Parameters
[in]stateState of the multibody system
[in]activationActivation model

◆ CostModelAbstractTpl() [3/4]

CostModelAbstractTpl ( boost::shared_ptr< StateAbstract state,
const std::size_t  nr,
const std::size_t  nu 
)

Initialize the cost model.

We use ActivationModelQuadTpl as a default activation model (i.e. \(a=\frac{1}{2}\|\mathbf{r}\|^2\))

Parameters
[in]stateState of the multibody system
[in]nrDimension of residual vector
[in]nuDimension of control vector

◆ CostModelAbstractTpl() [4/4]

CostModelAbstractTpl ( boost::shared_ptr< StateAbstract state,
const std::size_t  nr 
)

Initialize the cost model.

We use ActivationModelQuadTpl as a default activation model (i.e. \(a=\frac{1}{2}\|\mathbf{r}\|^2\)). Furthermore, the default nu value is obtained from StateAbstractTpl::get_nv().

Parameters
[in]stateState of the multibody system
[in]nrDimension of residual vector
[in]nuDimension of control vector

Member Function Documentation

◆ calc() [1/2]

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

Compute the cost value and its residual vector.

Parameters
[in]dataCost data
[in]xState point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]uControl input \(\mathbf{u}\in\mathbb{R}^{nu}\)

◆ calcDiff() [1/2]

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

Compute the Jacobian and Hessian of cost and its residual vector.

It computes the Jacobian and Hessian of the cost function. It assumes that calc() has been run first.

Parameters
[in]dataCost data
[in]xState point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]uControl input \(\mathbf{u}\in\mathbb{R}^{nu}\)

◆ createData()

◆ calc() [2/2]

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

Compute the cost value and its residual vector.

Parameters
[in]dataCost data
[in]xState point

◆ calcDiff() [2/2]

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

Compute the Jacobian and Hessian of cost and its residual vector.

Parameters
[in]dataCost data
[in]xState point

◆ set_referenceImpl()

◆ get_referenceImpl()


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