delpi::ExpressionCell Class Reference

Symbolic expression representing an addition between linear monomials. More...

#include <ExpressionCell.h>

Inheritance diagram for delpi::ExpressionCell:

Public Member Functions
ExpressionCell &	Add (const Variable &var, const mpq_class &coeff)
	Add a linear monomial \( c \cdot x \), where \( c \) is a constant and \( x \) is a Variable, to the current expression.
ExpressionCell &	Multiply (const mpq_class &coeff)
	Multiply all terms of the summation by a coeff.
ExpressionCell &	Divide (const mpq_class &coeff)
	Divide all terms of the summation by a coeff.
template<MapFromTo< Variable, mpq_class > T>
mpq_class	Evaluate (const T &env={}) const
	Evaluates using a given environment (by default, an empty environment).
Expression	Substitute (const SubstitutionMap &s) const
	Create a copy of this expression, replacing all occurrences of the variables in s with corresponding expressions in s.

Protected Attributes
std::size_t	hash_
	Cached hash of the object.
Expression::Addends	addends_
	Map between each variable and it coefficient as terms of the summation.

Additional Inherited Members
Protected Member Functions inherited from delpi::SelfReferenceCountingObject
virtual	~SelfReferenceCountingObject ()=default
	Virtual destructor for the SelfReferenceCountingObject.

Detailed Description

Symbolic expression representing an addition between linear monomials.

It can be used to encode expression of the kind

\[ \sum c_i \cdot x_i \]

where \( c_i \) is a constant and \( x_i \) is a Variable. Internally this class maintains a member variable addends_ to represent a mapping between each variable \( x_i \) to its rational \( c_i \).

Definition at line 27 of file ExpressionCell.h.

Member Function Documentation

Add()

ExpressionCell & delpi::ExpressionCell::Add	(	const Variable &	var,
		const mpq_class &	coeff )

Add a linear monomial \( c \cdot x \), where \( c \) is a constant and \( x \) is a Variable, to the current expression.

Parameters

var	variable of the linear monomial
coeff	coefficient of the linear monomial

Returns

reference to this object

Definition at line 70 of file ExpressionCell.cpp.

Divide()

ExpressionCell & delpi::ExpressionCell::Divide

(

const mpq_class &

coeff

)

Divide all terms of the summation by a coeff.

Parameters

coeff

coefficient all the terms will be divided by

Returns

reference to this object

Exceptions

delpi::DelpiException

division by 0 detected

Definition at line 92 of file ExpressionCell.cpp.

Evaluate()

template<MapFromTo< Variable, mpq_class > T>

template mpq_class delpi::ExpressionCell::Evaluate ( const T & env = {} ) const

nodiscard

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

Template Parameters

T	map from variable to value (i.e. std::map<Variable, mpq_class>, std::unordered_map<Variable, mpq_class>)

Parameters

env	map between each variable and its value

Returns

value of the expression in the given environment

Exceptions

std::exception

if there exists variable in this expression whose assignment is not provided by env

Definition at line 101 of file ExpressionCell.cpp.

Multiply()

ExpressionCell & delpi::ExpressionCell::Multiply

(

const mpq_class &

coeff

)

Multiply all terms of the summation by a coeff.

Parameters

coeff

coefficient all the terms will be mutiplied by

Returns

reference to this object

Definition at line 85 of file ExpressionCell.cpp.

Substitute()

Expression delpi::ExpressionCell::Substitute ( const SubstitutionMap & s ) const

nodiscard

Create a copy of this expression, replacing all occurrences of the variables in s with corresponding expressions in s.

Note that the substitutions occur simultaneously.

Expression e = x + 5 * y;
Substitution s = {{x, y}, {y, x}};
e.Substitute(s);  // returns y + 5 * x

Definition at line 108 of file ExpressionCell.cpp.

---

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

• delpi/symbolic/ExpressionCell.h
• delpi/symbolic/ExpressionCell.cpp