Membership

This page contains information about the member functions of the FroidurePin class related to testing membership.

const_reference libsemigroups::FroidurePin::at(element_index_type i)

Access element specified by index with bound checks.

This function attempts to enumerate until at least i + 1 elements have been found.

Parameters:

i – the index of the element to access.

Throws:

LibsemigroupsException – if i is greater than or equal to the return value of size().

Returns:

The element with index i (if any).

bool libsemigroups::FroidurePin::contains(const_reference x)

Test membership of an element.

Returns true if x belongs to this and false if it does not.

Note

This function may trigger a (partial) enumeration.

Parameters:

x – a const reference to a possible element.

Throws:

(None) – This function guarantees not to throw a LibsemigroupsException.

Returns:

A value of type bool.

element_index_type libsemigroups::FroidurePin::current_position(const_reference x) const

Find the position of an element with no enumeration.

Returns the position of the element x in the semigroup if it is already known to belong to the semigroup or UNDEFINED. This function finds the position of the element x if it is already known to belong to this, and UNDEFINED if not. If this is not yet fully enumerated, then this function may return UNDEFINED when x does belong to this.

See also

position and sorted_position.

Parameters:

x – a const reference to a possible element.

Throws:

(None) – This function guarantees not to throw a LibsemigroupsException.

Returns:

A value of type element_index_type.

const_reference libsemigroups::FroidurePin::generator(letter_type i) const

Returns the generator with specified index.

Note

Note that generator(i) is in general not in position i.

Parameters:

i – the index of a generator.

Throws:

LibsemigroupsException – if i is greater than or equal to number_of_generators().

Returns:

A value of type const_reference.

const_reference libsemigroups::FroidurePin::operator[](element_index_type i) const

Access element specified by index.

This function attempts to enumerate until at least i + 1 elements have been found.

Parameters:

i – the index of the element to access.

Throws:

(None) – This function guarantees not to throw a LibsemigroupsException.

Returns:

The element with index i (if any).

element_index_type libsemigroups::FroidurePin::position(const_reference x)

Find the position of an element with enumeration if necessary.

Returns the position of x in this, or UNDEFINED if x is not an element of this.

See also

current_position and sorted_position.

Parameters:

x – a const reference to a possible element.

Throws:

(None) – This function guarantees not to throw a LibsemigroupsException.

Returns:

A value of type element_index_type.

const_reference libsemigroups::FroidurePin::sorted_at(element_index_type i)

Access element specified by sorted index with bound checks.

This function triggers a full enumeration, and the parameter i is the index when the elements are sorted by Less.

Parameters:

i – the sorted index of the element to access.

Throws:

LibsemigroupsException – if i is greater than or equal to the return value of size().

Returns:

The element with index i (if any).

element_index_type libsemigroups::FroidurePin::sorted_position(const_reference x)

Returns the sorted index of an element.

Returns the position of x in the elements of this when they are sorted by Less, or UNDEFINED if x is not an element of this.

See also

current_position and position.

Parameters:

x – a const reference to a possible element.

Throws:

(None) – This function guarantees not to throw a LibsemigroupsException.

Returns:

A value of type element_index_type.