ExpressionCell Class Reference

Detailed Description

Represents an abstract class which is the base of concrete symbolic-expression classes.

Note

It provides virtual function, ExpressionCell::Display, because operator<< is not allowed to be a virtual function.

#include <drake/common/symbolic/expression/expression_cell.h>

Public Member Functions
virtual	~ExpressionCell ()
std::atomic< int > &	use_count () const
	Returns the intrusive use count (ala boost::intrusive_ptr).
ExpressionKind	get_kind () const
	Returns expression kind.
virtual void	HashAppendDetail (DelegatingHasher *) const =0
	Sends all hash-relevant bytes for this ExpressionCell type into the given hasher, per the hash_append generic hashing concept – except for get_kind(), because Expression already sends that.
virtual Variables	GetVariables () const =0
	Collects variables in expression.
virtual bool	EqualTo (const ExpressionCell &c) const =0
	Checks structural equality.
virtual bool	Less (const ExpressionCell &c) const =0
	Provides lexicographical ordering between expressions.
bool	is_polynomial () const
	Checks if this symbolic expression is convertible to Polynomial.
bool	is_expanded () const
	Checks if this symbolic expression is already expanded.
void	set_expanded ()
	Sets this symbolic expression as already expanded.
virtual double	Evaluate (const Environment &env) const =0
	Evaluates under a given environment (by default, an empty environment).
virtual Expression	Expand () const =0
	Expands out products and positive integer powers in expression.
virtual Expression	EvaluatePartial (const Environment &env) const =0
	Returns an Expression obtained by replacing all occurrences of the variables in env in the current expression cell with the corresponding values in env.
virtual Expression	Substitute (const Substitution &s) const =0
	Returns an Expression obtained by replacing all occurrences of the variables in s in the current expression cell with the corresponding expressions in s.
virtual Expression	Differentiate (const Variable &x) const =0
	Differentiates this symbolic expression with respect to the variable var.
virtual std::ostream &	Display (std::ostream &os) const =0
	Outputs string representation of expression into output stream os.
Does not allow copy, move, or assignment
	ExpressionCell (const ExpressionCell &)=delete
ExpressionCell &	operator= (const ExpressionCell &)=delete
	ExpressionCell (ExpressionCell &&)=delete
ExpressionCell &	operator= (ExpressionCell &&)=delete

Protected Member Functions
	ExpressionCell (ExpressionKind k, bool is_poly, bool is_expanded)
	Constructs ExpressionCell of kind k with is_poly and is_expanded, with a use_count of zero.

Constructor & Destructor Documentation

ExpressionCell() [1/3]

ExpressionCell ( const ExpressionCell & )

delete

ExpressionCell() [2/3]

ExpressionCell ( ExpressionCell && )

delete

~ExpressionCell()

virtual ~ExpressionCell ( )

virtual

ExpressionCell() [3/3]

ExpressionCell ( ExpressionKind k, bool is_poly, bool is_expanded )

protected

Constructs ExpressionCell of kind k with is_poly and is_expanded, with a use_count of zero.

Member Function Documentation

Differentiate()

virtual Expression Differentiate ( const Variable & x ) const

nodiscardpure virtual

Differentiates this symbolic expression with respect to the variable var.

Exceptions

std::exception

if it is not differentiable.

Implemented in ExpressionAbs, ExpressionAcos, ExpressionAdd, ExpressionAsin, ExpressionAtan2, ExpressionAtan, ExpressionCeiling, ExpressionCos, ExpressionCosh, ExpressionDiv, ExpressionExp, ExpressionFloor, ExpressionIfThenElse, ExpressionLog, ExpressionMax, ExpressionMin, ExpressionMul, ExpressionNaN, ExpressionPow, ExpressionSin, ExpressionSinh, ExpressionSqrt, ExpressionTan, ExpressionTanh, ExpressionUninterpretedFunction, and ExpressionVar.

Display()

virtual std::ostream & Display ( std::ostream & os ) const

pure virtual

Outputs string representation of expression into output stream os.

Implemented in ExpressionAbs, ExpressionAcos, ExpressionAdd, ExpressionAsin, ExpressionAtan2, ExpressionAtan, ExpressionCeiling, ExpressionCos, ExpressionCosh, ExpressionDiv, ExpressionExp, ExpressionFloor, ExpressionIfThenElse, ExpressionLog, ExpressionMax, ExpressionMin, ExpressionMul, ExpressionNaN, ExpressionPow, ExpressionSin, ExpressionSinh, ExpressionSqrt, ExpressionTan, ExpressionTanh, ExpressionUninterpretedFunction, and ExpressionVar.

EqualTo()

virtual bool EqualTo ( const ExpressionCell & c ) const

nodiscardpure virtual

Checks structural equality.

Implemented in BinaryExpressionCell, ExpressionAdd, ExpressionIfThenElse, ExpressionMul, ExpressionNaN, ExpressionUninterpretedFunction, ExpressionVar, and UnaryExpressionCell.

Evaluate()

virtual double Evaluate ( const Environment & env ) const

nodiscardpure virtual

Evaluates under a given environment (by default, an empty environment).

Exceptions

std::exception

if NaN is detected during evaluation.

Implemented in BinaryExpressionCell, ExpressionAdd, ExpressionIfThenElse, ExpressionMul, ExpressionNaN, ExpressionUninterpretedFunction, ExpressionVar, and UnaryExpressionCell.

EvaluatePartial()

virtual Expression EvaluatePartial ( const Environment & env ) const

nodiscardpure virtual

Returns an Expression obtained by replacing all occurrences of the variables in env in the current expression cell with the corresponding values in env.

Exceptions

std::exception

if NaN is detected during substitution.

Implemented in ExpressionAbs, ExpressionAcos, ExpressionAdd, ExpressionAsin, ExpressionAtan2, ExpressionAtan, ExpressionCeiling, ExpressionCos, ExpressionCosh, ExpressionDiv, ExpressionExp, ExpressionFloor, ExpressionIfThenElse, ExpressionLog, ExpressionMax, ExpressionMin, ExpressionMul, ExpressionNaN, ExpressionPow, ExpressionSin, ExpressionSinh, ExpressionSqrt, ExpressionTan, ExpressionTanh, ExpressionUninterpretedFunction, and ExpressionVar.

Expand()

virtual Expression Expand ( ) const

nodiscardpure virtual

Expands out products and positive integer powers in expression.

Exceptions

std::exception

if NaN is detected during expansion.

Implemented in ExpressionAbs, ExpressionAcos, ExpressionAdd, ExpressionAsin, ExpressionAtan2, ExpressionAtan, ExpressionCeiling, ExpressionCos, ExpressionCosh, ExpressionDiv, ExpressionExp, ExpressionFloor, ExpressionIfThenElse, ExpressionLog, ExpressionMax, ExpressionMin, ExpressionMul, ExpressionNaN, ExpressionPow, ExpressionSin, ExpressionSinh, ExpressionSqrt, ExpressionTan, ExpressionTanh, ExpressionUninterpretedFunction, and ExpressionVar.

get_kind()

ExpressionKind get_kind ( ) const

nodiscard

Returns expression kind.

GetVariables()

virtual Variables GetVariables ( ) const

nodiscardpure virtual

Collects variables in expression.

Implemented in BinaryExpressionCell, ExpressionAdd, ExpressionIfThenElse, ExpressionMul, ExpressionNaN, ExpressionUninterpretedFunction, ExpressionVar, and UnaryExpressionCell.

HashAppendDetail()

virtual void HashAppendDetail ( DelegatingHasher * ) const

pure virtual

Sends all hash-relevant bytes for this ExpressionCell type into the given hasher, per the hash_append generic hashing concept – except for get_kind(), because Expression already sends that.

Implemented in BinaryExpressionCell, ExpressionAdd, ExpressionIfThenElse, ExpressionMul, ExpressionNaN, ExpressionUninterpretedFunction, ExpressionVar, and UnaryExpressionCell.

is_expanded()

bool is_expanded ( ) const

nodiscard

Checks if this symbolic expression is already expanded.

is_polynomial()

bool is_polynomial ( ) const

nodiscard

Checks if this symbolic expression is convertible to Polynomial.

Less()

virtual bool Less ( const ExpressionCell & c ) const

nodiscardpure virtual

Provides lexicographical ordering between expressions.

Implemented in BinaryExpressionCell, ExpressionAdd, ExpressionIfThenElse, ExpressionMul, ExpressionNaN, ExpressionUninterpretedFunction, ExpressionVar, and UnaryExpressionCell.

operator=() [1/2]

ExpressionCell & operator= ( const ExpressionCell & )

delete

operator=() [2/2]

ExpressionCell & operator= ( ExpressionCell && )

delete

set_expanded()

void set_expanded

(

)

Sets this symbolic expression as already expanded.

Substitute()

virtual Expression Substitute ( const Substitution & s ) const

nodiscardpure virtual

Returns an Expression obtained by replacing all occurrences of the variables in s in the current expression cell with the corresponding expressions in s.

Exceptions

std::exception

if NaN is detected during substitution.

Implemented in ExpressionAbs, ExpressionAcos, ExpressionAdd, ExpressionAsin, ExpressionAtan2, ExpressionAtan, ExpressionCeiling, ExpressionCos, ExpressionCosh, ExpressionDiv, ExpressionExp, ExpressionFloor, ExpressionIfThenElse, ExpressionLog, ExpressionMax, ExpressionMin, ExpressionMul, ExpressionNaN, ExpressionPow, ExpressionSin, ExpressionSinh, ExpressionSqrt, ExpressionTan, ExpressionTanh, ExpressionUninterpretedFunction, and ExpressionVar.

use_count()

std::atomic< int > & use_count

(

)

const

Returns the intrusive use count (ala boost::intrusive_ptr).

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

• drake/common/symbolic/expression/expression_cell.h