smats::Environment< T > Class Template Reference

#include <environment.h>

Public Types
using	key_type = Variable
using	mapped_type = T
using	map = std::unordered_map<key_type, T>
using	value_type = map::value_type
using	iterator = map::iterator
using	const_iterator = map::const_iterator

Public Member Functions
	Environment ()=default
	Environment (std::initializer_list< value_type > init)
	Environment (std::span< const value_type > init)
	Environment (std::initializer_list< key_type > vars)
	Environment (std::span< const key_type > vars)
	Environment (map m)
iterator	begin ()
iterator	end ()
const_iterator	begin () const
const_iterator	end () const
const_iterator	cbegin () const
const_iterator	cend () const
void	insert (const key_type &key, const T &elem)
void	insert_or_assign (const key_type &key, const T &elem)
bool	empty () const
std::size_t	size () const
Variables	domain () const
bool	contains (const key_type &key) const
iterator	find (const key_type &key)
const_iterator	find (const key_type &key) const
const T &	at (const key_type &key) const
T &	operator[] (const key_type &key)
const T &	operator[] (const key_type &key) const
bool	operator== (const Environment< T > &other) const

Private Attributes
map	map_
	map between variables and values

Detailed Description

template<class T>
class smats::Environment< T >

Represents a symbolic environment (mapping from a variable to a value).

This class is used when we evaluate symbolic expressions or formulas which include unquantified (free) variables. Here are examples:

const Variable var_x{"x"};
const Variable var_y{"y"};
const Expression x{var_x};
const Expression y{var_x};
const Expression e1{x + y};
const Expression e2{x - y};
const Formula f{e1 > e2};
 
// env maps var_x to 2.0 and var_y to 3.0
const Environment env{{var_x, 2.0}, {var_y, 3.0}};
 
const numeric_type res1 = e1.Evaluate(env);  // x + y => 2.0 + 3.0 =>  5.0
const numeric_type res2 = e2.Evaluate(env);  // x - y => 2.0 - 3.0 => -1.0
const bool res = f.Evaluate(env);  // x + y > x - y => 5.0 >= -1.0 => True

Template Parameters

T	type of the value

Constructor & Destructor Documentation

Environment() [1/6]

template<class T >

smats::Environment< T >::Environment ( )

default

Construct a new environment object.

Environment() [2/6]

template<class T >

smats::Environment< T >::Environment ( std::initializer_list< value_type > init )

explicit

Construct a new environment object from a list of (Variable, numeric_type).

Parameters

init	initializer list of (Variable, numeric_type)

Exceptions

std::runtime_exception

if init include a dummy variable or a NaN value.

Environment() [3/6]

template<class T >

smats::Environment< T >::Environment ( std::span< const value_type > init )

explicit

Construct a new environment object from a list of (Variable, numeric_type).

Parameters

init	initializer list of (Variable, numeric_type)

Exceptions

std::runtime_exception

if init include a dummy variable or a NaN value.

Environment() [4/6]

template<class T >

smats::Environment< T >::Environment ( std::initializer_list< key_type > vars )

explicit

Construct a new environment object from a list of variables.

Initializes the variables with 0.0.

Parameters

vars	initializer list of variables

Exceptions

std::runtime_exception

if vars include a dummy variable.

Environment() [5/6]

template<class T >

smats::Environment< T >::Environment ( std::span< const key_type > vars )

explicit

Construct a new environment object from a list of variables.

Initializes the variables with 0.0.

Parameters

vars	initializer list of variables

Exceptions

std::runtime_exception

if vars include a dummy variable.

Environment() [6/6]

template<class T >

smats::Environment< T >::Environment ( map m )

explicit

Construct a new environment object from the map m between variables and values.

Parameters

m	map between variables and values

Exceptions

std::runtime_exception

if m include a dummy variable or a NaN value.

Member Function Documentation

at()

template<class T >

const T & smats::Environment< T >::at ( const key_type & key ) const

nodiscard

Get a reference to the value that is mapped to a key equivalent to key.

Parameters

key	key of the element to find

Returns

reference to the mapped value of the requested key

Exceptions

std::out_of_range

if the key does not exist

begin() [1/2]

template<class T >

iterator smats::Environment< T >::begin ( )

inline

Get read-only access to the iterator to the beginning of the environment.

Returns

iterator to the beginning of the environment

begin() [2/2]

template<class T >

const_iterator smats::Environment< T >::begin ( ) const

inlinenodiscard

Get read-only access to the const iterator to the beginning of the environment.

Returns

const iterator to the beginning of the environment

cbegin()

template<class T >

const_iterator smats::Environment< T >::cbegin ( ) const

inlinenodiscard

Get read-only access to the const iterator to the beginning of the environment.

Returns

const iterator to the beginning of the environment

cend()

template<class T >

const_iterator smats::Environment< T >::cend ( ) const

inlinenodiscard

Get read-only access to the const iterator to the end of the environment.

Returns

const iterator to the end of the environment

contains()

template<class T >

bool smats::Environment< T >::contains ( const key_type & key ) const

inlinenodiscard

Check if the environment contains the key.

Parameters

key	key to check

Returns

true if the environment contains key

false if the environment doesn't contain key

domain()

template<class T >

Variables smats::Environment< T >::domain ( ) const

nodiscard

Get read-only access to the domain of the environment.

Returns

domain of the environment

empty()

template<class T >

bool smats::Environment< T >::empty ( ) const

inlinenodiscard

Check whether the environment is empty.

Returns

true if the environment is empty

false if the environment is not empty

end() [1/2]

template<class T >

iterator smats::Environment< T >::end ( )

inline

Get read-only access to the iterator to the end of the environment.

Returns

iterator to the end of the environment

end() [2/2]

template<class T >

const_iterator smats::Environment< T >::end ( ) const

inlinenodiscard

Get read-only access to the const iterator to the end of the environment.

Returns

const iterator to the end of the environment

find() [1/2]

template<class T >

iterator smats::Environment< T >::find ( const key_type & key )

inline

Finds element with specific key.

Parameters

key	key to find

Returns

iterator to the element with key equivalent to key.

find() [2/2]

template<class T >

const_iterator smats::Environment< T >::find ( const key_type & key ) const

inlinenodiscard

Finds element with specific key.

Parameters

key	key to find

Returns

const_iterator to the element with key equivalent to key.

insert()

template<class T >

void smats::Environment< T >::insert	(	const key_type &	key,
		const T &	elem )

Insert a pair (key, elem) if this environment doesn't contain key.

Similar to insert function in map, if the key already exists in this environment, then calling insert(key, elem) doesn't change the existing key-value in this environment.

Parameters

key	key to insert
elem	value to insert

insert_or_assign()

template<class T >

void smats::Environment< T >::insert_or_assign	(	const key_type &	key,
		const T &	elem )

Insert a pair (key, elem) or assign elem to the existing key if it exists.

Parameters

key	key to insert
elem	value to insert

operator[]() [1/2]

template<class T >

T & smats::Environment< T >::operator[]

(

const key_type &

key

)

Returns a reference to the value that is mapped to a key equivalent to key, performing an insertion if such key does not already exist.

Parameters

key	key of the element to find or insert

operator[]() [2/2]

template<class T >

const T & smats::Environment< T >::operator[]

(

const key_type &

key

)

const

Returns a constant reference to the value that is mapped to a key equivalent to key.

Parameters

key	key of the element to find

Returns

reference to the mapped value of the requested key

Exceptions

std::out_of_range

if the key does not exist

size()

template<class T >

std::size_t smats::Environment< T >::size ( ) const

inlinenodiscard

Get read-only access to the number of elements of the environment.

Returns

number of elements of the environment

---

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

• smats/symbolic/environment.h
• smats/symbolic/environment.cpp