QuadraticCost Class Reference

Detailed Description

Implements a cost of the form

\[ .5 x'Qx + b'x + c \]

.

#include <drake/solvers/cost.h>

Public Member Functions
template<typename DerivedQ , typename Derivedb >
	QuadraticCost (const Eigen::MatrixBase< DerivedQ > &Q, const Eigen::MatrixBase< Derivedb > &b, double c=0., std::optional< bool > is_hessian_psd=std::nullopt)
	Constructs a cost of the form \[ .5 x'Qx + b'x + c \] . More...
	~QuadraticCost () override
const Eigen::MatrixXd &	Q () const
	Returns the symmetric matrix Q, as the Hessian of the cost. More...
const Eigen::VectorXd &	b () const
double	c () const
bool	is_convex () const
	Returns true if this cost is convex. More...
template<typename DerivedQ , typename DerivedB >
void	UpdateCoefficients (const Eigen::MatrixBase< DerivedQ > &new_Q, const Eigen::MatrixBase< DerivedB > &new_b, double new_c=0., std::optional< bool > is_hessian_psd=std::nullopt)
	Updates the quadratic and linear term of the constraint. More...
Does not allow copy, move, or assignment
	QuadraticCost (const QuadraticCost &)=delete
QuadraticCost &	operator= (const QuadraticCost &)=delete
	QuadraticCost (QuadraticCost &&)=delete
QuadraticCost &	operator= (QuadraticCost &&)=delete
Public Member Functions inherited from Cost
	Cost (const Cost &)=delete
Cost &	operator= (const Cost &)=delete
	Cost (Cost &&)=delete
Cost &	operator= (Cost &&)=delete
Public Member Functions inherited from EvaluatorBase
virtual	~EvaluatorBase ()
void	Eval (const Eigen::Ref< const Eigen::VectorXd > &x, Eigen::VectorXd *y) const
	Evaluates the expression. More...
void	Eval (const Eigen::Ref< const AutoDiffVecXd > &x, AutoDiffVecXd *y) const
	Evaluates the expression. More...
void	Eval (const Eigen::Ref< const VectorX< symbolic::Variable >> &x, VectorX< symbolic::Expression > *y) const
	Evaluates the expression. More...
void	set_description (const std::string &description)
	Set a human-friendly description for the evaluator. More...
const std::string &	get_description () const
	Getter for a human-friendly description for the evaluator. More...
std::ostream &	Display (std::ostream &os, const VectorX< symbolic::Variable > &vars) const
	Formats this evaluator into the given stream using vars for the bound decision variable names. More...
std::ostream &	Display (std::ostream &os) const
	Formats this evaluator into the given stream, without displaying the decision variables it is bound to. More...
std::string	ToLatex (const VectorX< symbolic::Variable > &vars, int precision=3) const
	Returns a LaTeX string describing this evaluator. More...
int	num_vars () const
	Getter for the number of variables, namely the number of rows in x, as used in Eval(x, y). More...
int	num_outputs () const
	Getter for the number of outputs, namely the number of rows in y, as used in Eval(x, y). More...
void	SetGradientSparsityPattern (const std::vector< std::pair< int, int >> &gradient_sparsity_pattern)
	Set the sparsity pattern of the gradient matrix ∂y/∂x (the gradient of y value in Eval, w.r.t x in Eval) . More...
const std::optional< std::vector< std::pair< int, int > > > &	gradient_sparsity_pattern () const
	Returns the vector of (row_index, col_index) that contains all the entries in the gradient of Eval function (∂y/∂x) whose value could be non-zero, namely if ∂yᵢ/∂xⱼ could be non-zero, then the pair (i, j) is in gradient_sparsity_pattern. More...
	EvaluatorBase (const EvaluatorBase &)=delete
EvaluatorBase &	operator= (const EvaluatorBase &)=delete
	EvaluatorBase (EvaluatorBase &&)=delete
EvaluatorBase &	operator= (EvaluatorBase &&)=delete

Additional Inherited Members
Protected Member Functions inherited from Cost
	Cost (int num_vars, const std::string &description="")
	Constructs a cost evaluator. More...
Protected Member Functions inherited from EvaluatorBase
	EvaluatorBase (int num_outputs, int num_vars, const std::string &description="")
	Constructs a evaluator. More...
void	set_num_outputs (int num_outputs)

Constructor & Destructor Documentation

QuadraticCost() [1/3]

QuadraticCost ( const QuadraticCost &  )

delete

QuadraticCost() [2/3]

QuadraticCost ( QuadraticCost &&  )

delete

QuadraticCost() [3/3]

QuadraticCost	(	const Eigen::MatrixBase< DerivedQ > &	Q,
		const Eigen::MatrixBase< Derivedb > &	b,
		double	c = 0.,
		std::optional< bool >	is_hessian_psd = std::nullopt
	)

Constructs a cost of the form

\[ .5 x'Qx + b'x + c \]

.

Parameters

Q	Quadratic term.
b	Linear term.
c	(optional) Constant term.
is_hessian_psd	(optional) Indicates if the Hessian matrix Q is positive semidefinite (psd) or not. If set to true, then the user guarantees that Q is psd; if set to false, then the user guarantees that Q is not psd. If set to std::nullopt, then the constructor will check if Q is psd or not. The default is std::nullopt. To speed up the constructor, set is_hessian_psd to either true or false.

~QuadraticCost()

~QuadraticCost ( )

override

Member Function Documentation

b()

const Eigen::VectorXd& b

(

)

const

c()

double c

(

)

const

is_convex()

bool is_convex

(

)

const

Returns true if this cost is convex.

A quadratic cost if convex if and only if its Hessian matrix Q is positive semidefinite.

operator=() [1/2]

QuadraticCost& operator= ( const QuadraticCost &  )

delete

operator=() [2/2]

QuadraticCost& operator= ( QuadraticCost &&  )

delete

Q()

const Eigen::MatrixXd& Q

(

)

const

Returns the symmetric matrix Q, as the Hessian of the cost.

UpdateCoefficients()

void UpdateCoefficients	(	const Eigen::MatrixBase< DerivedQ > &	new_Q,
		const Eigen::MatrixBase< DerivedB > &	new_b,
		double	new_c = 0.,
		std::optional< bool >	is_hessian_psd = std::nullopt
	)

Updates the quadratic and linear term of the constraint.

The new matrices need to have the same dimension as before.

Parameters

new_Q	New quadratic term.
new_b	New linear term.
new_c	(optional) New constant term.
is_hessian_psd	(optional) Indicates if the Hessian matrix Q is positive semidefinite (psd) or not. If set to true, then the user guarantees that Q is psd; if set to false, then the user guarantees that Q is not psd. If set to std::nullopt, then this function will check if Q is psd or not. The default is std::nullopt. To speed up the computation, set is_hessian_psd to either true or false.

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

• drake/solvers/cost.h