towr::SoftConstraint Class Reference

Converts a constraint to a cost by weighing the quadratic violations. More...

#include <soft_constraint.h>

Inheritance diagram for towr::SoftConstraint:

Public Types
using	ConstraintPtr = Component::Ptr
Public Types inherited from ifopt::Component
typedef Eigen::SparseMatrix< double, Eigen::RowMajor >	Jacobian
typedef std::shared_ptr< Component >	Ptr
typedef std::vector< Bounds >	VecBound
typedef Eigen::VectorXd	VectorXd

Public Member Functions
	SoftConstraint (const ConstraintPtr &constraint)
	Creates a soft constraint (=cost) from a hard constraint. More...
virtual	~SoftConstraint ()=default
Public Member Functions inherited from ifopt::Component
	Component (int num_rows, const std::string &name)
std::string	GetName () const
int	GetRows () const
virtual void	Print (double tolerance, int &index_start) const
void	SetRows (int num_rows)
virtual	~Component ()=default

Private Member Functions
VecBound	GetBounds () const final
Jacobian	GetJacobian () const override
	The row-vector of derivatives of the cost term. More...
VectorXd	GetValues () const override
	average value of each upper and lower bound. More...
void	SetVariables (const VectorXd &x) final

Private Attributes
VectorXd	b_
ConstraintPtr	constraint_
VectorXd	W_
	weights how each constraint violation contributes to the cost. More...

Additional Inherited Members
Static Public Attributes inherited from ifopt::Component
static const int	kSpecifyLater

Detailed Description

Converts a constraint to a cost by weighing the quadratic violations.

Let constraint g(x) R^m with upper bound b_u and lower bound b_l. Let

g'(x) = g(x) - 0.5(b_u+b_l) = g(x) - b

And it's derivative

dg'(x)/dx = J(x).

Define a cost as

c(x) = 0.5 * g'^T * W * g', where W = diag(w1,...,wm).

Then the gradient of the cost is defined as:

dc(x)/dx = (g'(x)^T * W * J)^T = J^T * W * (g(x)-b).

Definition at line 59 of file soft_constraint.h.

Member Typedef Documentation

using towr::SoftConstraint::ConstraintPtr = Component::Ptr

Definition at line 61 of file soft_constraint.h.

Constructor & Destructor Documentation

towr::SoftConstraint::SoftConstraint

(

const ConstraintPtr &

constraint

)

Creates a soft constraint (=cost) from a hard constraint.

Parameters

constraint

The fully initialized constraint.

Weights are set to identity, so each constraint violation contributes equally to the cost.

Definition at line 34 of file soft_constraint.cc.

virtual towr::SoftConstraint::~SoftConstraint ( )

virtualdefault

Member Function Documentation

VecBound towr::SoftConstraint::GetBounds ( ) const

inlinefinalprivatevirtual

Implements ifopt::Component.

Definition at line 93 of file soft_constraint.h.

SoftConstraint::Jacobian towr::SoftConstraint::GetJacobian ( ) const

overrideprivatevirtual

The row-vector of derivatives of the cost term.

dc(x)/dx = J^T * W * (g-b)

Implements ifopt::Component.

Definition at line 61 of file soft_constraint.cc.

SoftConstraint::VectorXd towr::SoftConstraint::GetValues ( ) const

overrideprivatevirtual

average value of each upper and lower bound.

The quadratic constraint violation transformed to a cost.

c(x) = 0.5 * (g-b)^T * W * (g-b)

Implements ifopt::Component.

Definition at line 53 of file soft_constraint.cc.

void towr::SoftConstraint::SetVariables ( const VectorXd &  x )

inlinefinalprivatevirtual

Implements ifopt::Component.

Definition at line 94 of file soft_constraint.h.

Member Data Documentation

VectorXd towr::SoftConstraint::b_

private

Definition at line 76 of file soft_constraint.h.

ConstraintPtr towr::SoftConstraint::constraint_

private

Definition at line 74 of file soft_constraint.h.

VectorXd towr::SoftConstraint::W_

private

weights how each constraint violation contributes to the cost.

Definition at line 75 of file soft_constraint.h.

---

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

• soft_constraint.h
• soft_constraint.cc