ExpressionMul Class Reference

Detailed Description

Symbolic expression representing a multiplication of powers.

\[ c_0 \cdot \prod b_i^{e_i} \]

where \( c_0 \) is a constant and \( b_i \) and \( e_i \) are symbolic expressions.

Internally this class maintains a member variable constant_ representing \( c_0 \) and another member variable base_to_exponent_map_ representing a mapping from a base, \( b_i \) to its exponentiation \( e_i \).

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

Public Member Functions
	ExpressionMul (double constant, std::map< Expression, Expression > base_to_exponent_map)
	Constructs ExpressionMul from constant and base_to_exponent_map.
	~ExpressionMul () override
void	HashAppendDetail (DelegatingHasher *) const override
	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.
Variables	GetVariables () const override
	Collects variables in expression.
bool	EqualTo (const ExpressionCell &e) const override
	Checks structural equality.
bool	Less (const ExpressionCell &e) const override
	Provides lexicographical ordering between expressions.
double	Evaluate (const Environment &env) const override
	Evaluates under a given environment (by default, an empty environment).
Expression	Expand () const override
	Expands out products and positive integer powers in expression.
Expression	EvaluatePartial (const Environment &env) const override
	Returns an Expression obtained by replacing all occurrences of the variables in env in the current expression cell with the corresponding values in env.
Expression	Substitute (const Substitution &s) const override
	Returns an Expression obtained by replacing all occurrences of the variables in s in the current expression cell with the corresponding expressions in s.
Expression	Differentiate (const Variable &x) const override
	Differentiates this symbolic expression with respect to the variable var.
std::ostream &	Display (std::ostream &os) const override
	Outputs string representation of expression into output stream os.
double	get_constant () const
	Returns constant term.
const std::map< Expression, Expression > &	get_base_to_exponent_map () const
	Returns map from a term to its coefficient.
Public Member Functions inherited from ExpressionCell
virtual	~ExpressionCell ()
std::atomic< int > &	use_count () const
	Returns the intrusive use count (ala boost::intrusive_ptr).
ExpressionKind	get_kind () const
	Returns expression kind.
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.
	ExpressionCell (const ExpressionCell &)=delete
ExpressionCell &	operator= (const ExpressionCell &)=delete
	ExpressionCell (ExpressionCell &&)=delete
ExpressionCell &	operator= (ExpressionCell &&)=delete

Additional Inherited Members
Protected Member Functions inherited from ExpressionCell
	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

ExpressionMul()

ExpressionMul	(	double	constant,
		std::map< Expression, Expression >	base_to_exponent_map )

Constructs ExpressionMul from constant and base_to_exponent_map.

~ExpressionMul()

~ExpressionMul ( )

override

Member Function Documentation

Differentiate()

Expression Differentiate ( const Variable & x ) const

nodiscardoverridevirtual

Differentiates this symbolic expression with respect to the variable var.

Exceptions

std::exception

if it is not differentiable.

Implements ExpressionCell.

Display()

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

overridevirtual

Outputs string representation of expression into output stream os.

Implements ExpressionCell.

EqualTo()

bool EqualTo ( const ExpressionCell & c ) const

nodiscardoverridevirtual

Checks structural equality.

Implements ExpressionCell.

Evaluate()

double Evaluate ( const Environment & env ) const

nodiscardoverridevirtual

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

Exceptions

std::exception

if NaN is detected during evaluation.

Implements ExpressionCell.

EvaluatePartial()

Expression EvaluatePartial ( const Environment & env ) const

nodiscardoverridevirtual

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.

Implements ExpressionCell.

Expand()

Expression Expand ( ) const

nodiscardoverridevirtual

Expands out products and positive integer powers in expression.

Exceptions

std::exception

if NaN is detected during expansion.

Implements ExpressionCell.

get_base_to_exponent_map()

const std::map< Expression, Expression > & get_base_to_exponent_map ( ) const

nodiscard

Returns map from a term to its coefficient.

get_constant()

double get_constant ( ) const

nodiscard

Returns constant term.

GetVariables()

Variables GetVariables ( ) const

nodiscardoverridevirtual

Collects variables in expression.

Implements ExpressionCell.

HashAppendDetail()

void HashAppendDetail ( DelegatingHasher * ) const

overridevirtual

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.

Implements ExpressionCell.

Less()

bool Less ( const ExpressionCell & c ) const

nodiscardoverridevirtual

Provides lexicographical ordering between expressions.

Implements ExpressionCell.

Substitute()

Expression Substitute ( const Substitution & s ) const

nodiscardoverridevirtual

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.

Implements ExpressionCell.

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

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