lal::iterators::Q_iterator< GRAPH, is_directed, > Class Template Reference

Iterator over the set of pairs of independent edges of a graph. More...

#include <Q_iterator.hpp>

Public Member Functions
	Q_iterator (const GRAPH &g) noexcept
	Constructor. More...
	~Q_iterator ()=default
	Default destructor.
bool	end () const noexcept
	Returns true if the end of the iteration was reached.
const edge_pair &	get_edge_pair () const noexcept
	Returns the current edge pair.
edge_pair_t	get_edge_pair_t () const noexcept
	Returns the current edge pair.
edge_pair	yield_edge_pair () noexcept
	Returns the current edge pair and advances the iterator.
void	next () noexcept
	Moves the iterator to the next pair, if there is any.
void	reset () noexcept
	Sets the iterator at the beginning of the set of edges.

Private Member Functions
void	__reset () noexcept
	Sets the iterator at the beginning of the set of edges.
edge_pair	make_current_pair () const noexcept
	Returns the current pair of independent edges. More...
bool	share_nodes_pointer (const node s, const std::size_t pt, const node u, const std::size_t pv) const noexcept
	Returns whether two edges share vertices or not. More...
bool	share_nodes (const node s, const node t, const node u, const node v) const noexcept
	Returns whether two edges share vertices or not. More...
template<bool isdir = is_directed, std::enable_if_t< isdir, bool > = true>
std::tuple< bool, E_pointer, E_pointer >	find_next_pair (node s, std::size_t pt, node u, std::size_t pv) noexcept
	Find the next pair in a directed graph.
template<bool isdir = is_directed, std::enable_if_t< not isdir, bool > = true>
std::tuple< bool, E_pointer, E_pointer >	find_next_pair (node s, std::size_t pt, node u, std::size_t pv) noexcept
	Find the next pair in an undirected graph.

Private Attributes
const GRAPH &	m_G
	Graph we are iterating on.
const uint64_t	m_n
	Number of vertices.
E_pointer	m_cur1 = E_pointer(0,0)
	Current pointers to the first edge.
E_pointer	m_cur2 = E_pointer(0,0)
	Current pointers to the second edge.
bool	m_exists_next = true
	Is there a next pair of independent edges?
bool	m_reached_end = false
	Has the end of the iteration been reached?
edge_pair	m_cur_pair = { {0,0}, {0,0} }
	Current pair of independent edges.

Detailed Description

template<typename GRAPH, bool is_directed = std::is_base_of_v<graphs::directed_graph, GRAPH>, std::enable_if_t< std::is_base_of_v< graphs::directed_graph, GRAPH >||std::is_base_of_v< graphs::undirected_graph, GRAPH >, bool > = true>
class lal::iterators::Q_iterator< GRAPH, is_directed, >

Iterator over the set of pairs of independent edges of a graph.

This class is used to easily iterate over the elements of the set \(Q\) of a graph.

This class iterates over the independent pairs of edges of a graph. For undirected graphs, the edges of the pair returned are edges \((u,v)\) so that the inequality \(u < v\) always holds. For directed graphs, this is not always true, since the edges returned always has left-to-right direction.

This class has to be initialised with a constant reference to a graph.

A possible usage of this class is the following:

Q_iterator it(g); // g is a graph
while (not it.end()) {
    const auto [e1,e2] = it.get_edge_pair();
    // ...
        it.next();
}

or, in a more compact way:

Q_iterator it(g); // g is a graph
while (not it.end()) {
    const auto [e1,e2] = it.yield_edge_pair();
    // ...
}

Alternatively, the lal::iterators::Q_iterator object can be used in a for loop:

for (Q_iterator it(g); not it.end(); it.next()) {
    const auto [e1,e2] = it.get_edge_pair();
    // ...
}

Constructor & Destructor Documentation

Q_iterator()

template<typename GRAPH , bool is_directed = std::is_base_of_v<graphs::directed_graph, GRAPH>, std::enable_if_t< std::is_base_of_v< graphs::directed_graph, GRAPH >||std::is_base_of_v< graphs::undirected_graph, GRAPH >, bool > = true>

lal::iterators::Q_iterator< GRAPH, is_directed, >::Q_iterator ( const GRAPH &  g )

inlinenoexcept

Constructor.

Parameters

g	Constant reference to the graph over which we iterate.

Member Function Documentation

make_current_pair()

template<typename GRAPH , bool is_directed = std::is_base_of_v<graphs::directed_graph, GRAPH>, std::enable_if_t< std::is_base_of_v< graphs::directed_graph, GRAPH >||std::is_base_of_v< graphs::undirected_graph, GRAPH >, bool > = true>

edge_pair lal::iterators::Q_iterator< GRAPH, is_directed, >::make_current_pair ( ) const

inlineprivatenoexcept

Returns the current pair of independent edges.

These are the edges pointed by attribute m_cur1 and by attribute m_cur2.

share_nodes()

template<typename GRAPH , bool is_directed = std::is_base_of_v<graphs::directed_graph, GRAPH>, std::enable_if_t< std::is_base_of_v< graphs::directed_graph, GRAPH >||std::is_base_of_v< graphs::undirected_graph, GRAPH >, bool > = true>

bool lal::iterators::Q_iterator< GRAPH, is_directed, >::share_nodes ( const node  s, const node  t, const node  u, const node  v  ) const

inlineprivatenoexcept

Returns whether two edges share vertices or not.

Parameters

s	First node of the first edge.
t	Second node of the first edge.
u	First node of the second edge.
v	Second node of the second edge.

Returns

Whether or not the edges share nodes.

share_nodes_pointer()

template<typename GRAPH , bool is_directed = std::is_base_of_v<graphs::directed_graph, GRAPH>, std::enable_if_t< std::is_base_of_v< graphs::directed_graph, GRAPH >||std::is_base_of_v< graphs::undirected_graph, GRAPH >, bool > = true>

bool lal::iterators::Q_iterator< GRAPH, is_directed, >::share_nodes_pointer ( const node  s, const std::size_t  pt, const node  u, const std::size_t  pv  ) const

inlineprivatenoexcept

Returns whether two edges share vertices or not.

The edges are determined in the following manner. The first edge is determined by node s, and the node pointed by pt. The second edge is determined by node u, and the node pointed by pv.

Parameters

s	First node of the first edge.
pt	Pointer to the second node of the first edge.
u	First node of the second edge.
pv	Pointer to the second node of the second edge.

Returns

Whether or not the edges share nodes.

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

• lal/iterators/Q_iterator.hpp