ExpressionCost Class Reference

Detailed Description

Impose a generic (potentially nonlinear) cost represented as a symbolic Expression.

Expression::Evaluate is called on every constraint evaluation.

Uses symbolic::Jacobian to provide the gradients to the AutoDiff method.

#include <drake/solvers/cost.h>

Public Member Functions
	ExpressionCost (const symbolic::Expression &e)
const VectorXDecisionVariable &	vars () const
const symbolic::Expression &	expression () const
Does not allow copy, move, or assignment
	ExpressionCost (const ExpressionCost &)=delete
ExpressionCost &	operator= (const ExpressionCost &)=delete
	ExpressionCost (ExpressionCost &&)=delete
ExpressionCost &	operator= (ExpressionCost &&)=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...
bool	is_thread_safe () const
	Returns whether it is safe to call Eval in parallel. More...
	EvaluatorBase (const EvaluatorBase &)=delete
EvaluatorBase &	operator= (const EvaluatorBase &)=delete
	EvaluatorBase (EvaluatorBase &&)=delete
EvaluatorBase &	operator= (EvaluatorBase &&)=delete

Protected Member Functions
void	DoEval (const Eigen::Ref< const Eigen::VectorXd > &x, Eigen::VectorXd *y) const override
	Implements expression evaluation for scalar type double. More...
void	DoEval (const Eigen::Ref< const AutoDiffVecXd > &x, AutoDiffVecXd *y) const override
	Implements expression evaluation for scalar type AutoDiffXd. More...
void	DoEval (const Eigen::Ref< const VectorX< symbolic::Variable >> &x, VectorX< symbolic::Expression > *y) const override
	Implements expression evaluation for scalar type symbolic::Expression. More...
std::ostream &	DoDisplay (std::ostream &, const VectorX< symbolic::Variable > &) const override
	NVI implementation of Display. More...
std::string	DoToLatex (const VectorX< symbolic::Variable > &, int) const override
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)
void	set_is_thread_safe (bool is_thread_safe)

Constructor & Destructor Documentation

ExpressionCost() [1/3]

ExpressionCost ( const ExpressionCost &  )

delete

ExpressionCost() [2/3]

ExpressionCost ( ExpressionCost &&  )

delete

ExpressionCost() [3/3]

ExpressionCost ( const symbolic::Expression &  e )

explicit

Member Function Documentation

DoDisplay()

std::ostream& DoDisplay ( std::ostream &  os, const VectorX< symbolic::Variable > &  vars  ) const

overrideprotectedvirtual

NVI implementation of Display.

The default implementation will report the NiceTypeName, get_description, and list the bound variables. Subclasses may override to customize the message.

Precondition

vars size is consistent with num_vars".

Reimplemented from EvaluatorBase.

DoEval() [1/3]

void DoEval ( const Eigen::Ref< const Eigen::VectorXd > &  x, Eigen::VectorXd *  y  ) const

overrideprotectedvirtual

Implements expression evaluation for scalar type double.

Parameters

x	Input vector.
y	Output vector.

Precondition

x must be of size num_vars x 1.

Postcondition

y will be of size num_outputs x 1.

Implements EvaluatorBase.

DoEval() [2/3]

void DoEval ( const Eigen::Ref< const AutoDiffVecXd > &  x, AutoDiffVecXd *  y  ) const

overrideprotectedvirtual

Implements expression evaluation for scalar type AutoDiffXd.

Parameters

x	Input vector.
y	Output vector.

Precondition

x must be of size num_vars x 1.

Postcondition

y will be of size num_outputs x 1.

Implements EvaluatorBase.

DoEval() [3/3]

void DoEval ( const Eigen::Ref< const VectorX< symbolic::Variable >> &  x, VectorX< symbolic::Expression > *  y  ) const

overrideprotectedvirtual

Implements expression evaluation for scalar type symbolic::Expression.

Parameters

[in]	x	Input vector.
[out]	y	Output vector.

Precondition

x must be of size num_vars x 1.

Postcondition

y will be of size num_outputs x 1.

Implements EvaluatorBase.

DoToLatex()

std::string DoToLatex ( const VectorX< symbolic::Variable > &  , int    ) const

overrideprotectedvirtual

Reimplemented from EvaluatorBase.

expression()

const symbolic::Expression& expression

(

)

const

Returns

the symbolic expression.

operator=() [1/2]

ExpressionCost& operator= ( const ExpressionCost &  )

delete

operator=() [2/2]

ExpressionCost& operator= ( ExpressionCost &&  )

delete

vars()

const VectorXDecisionVariable& vars

(

)

const

Returns

the list of the variables involved in the vector of expressions, in the order that they are expected to be received during DoEval. Any Binding that connects this constraint to decision variables should pass this list of variables to the Binding.

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

• drake/solvers/cost.h