ecency-mobile/ios/Pods/boost-for-react-native/boost/graph/hawick_circuits.hpp

382 lines
14 KiB
C++
Raw Normal View History

// Copyright Louis Dionne 2013
// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy
// at http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_GRAPH_HAWICK_CIRCUITS_HPP
#define BOOST_GRAPH_HAWICK_CIRCUITS_HPP
#include <algorithm>
#include <boost/assert.hpp>
#include <boost/foreach.hpp>
#include <boost/graph/graph_traits.hpp>
#include <boost/graph/one_bit_color_map.hpp>
#include <boost/graph/properties.hpp>
#include <boost/move/utility.hpp>
#include <boost/property_map/property_map.hpp>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
#include <boost/range/iterator.hpp>
#include <boost/tuple/tuple.hpp> // for boost::tie
#include <boost/type_traits/remove_reference.hpp>
#include <boost/utility/result_of.hpp>
#include <set>
#include <utility> // for std::pair
#include <vector>
namespace boost {
namespace hawick_circuits_detail {
//! @internal Functor returning all the vertices adjacent to a vertex.
struct get_all_adjacent_vertices {
template <typename Sig>
struct result;
template <typename This, typename Vertex, typename Graph>
struct result<This(Vertex, Graph)> {
private:
typedef typename remove_reference<Graph>::type RawGraph;
typedef graph_traits<RawGraph> Traits;
typedef typename Traits::adjacency_iterator AdjacencyIterator;
public:
typedef std::pair<AdjacencyIterator, AdjacencyIterator> type;
};
template <typename Vertex, typename Graph>
typename result<
get_all_adjacent_vertices(BOOST_FWD_REF(Vertex), BOOST_FWD_REF(Graph))
>::type
operator()(BOOST_FWD_REF(Vertex) v, BOOST_FWD_REF(Graph) g) const {
return adjacent_vertices(boost::forward<Vertex>(v),
boost::forward<Graph>(g));
}
};
//! @internal Functor returning a set of the vertices adjacent to a vertex.
struct get_unique_adjacent_vertices {
template <typename Sig>
struct result;
template <typename This, typename Vertex, typename Graph>
struct result<This(Vertex, Graph)> {
typedef std::set<typename remove_reference<Vertex>::type> type;
};
template <typename Vertex, typename Graph>
typename result<get_unique_adjacent_vertices(Vertex, Graph const&)>::type
operator()(Vertex v, Graph const& g) const {
typedef typename result<
get_unique_adjacent_vertices(Vertex, Graph const&)
>::type Set;
return Set(adjacent_vertices(v, g).first,
adjacent_vertices(v, g).second);
}
};
//! @internal
//! Return whether a container contains a given value.
//! This is not meant as a general purpose membership testing function; it
//! would have to be more clever about possible optimizations.
template <typename Container, typename Value>
bool contains(Container const& c, Value const& v) {
return std::find(boost::begin(c), boost::end(c), v) != boost::end(c);
}
/*!
* @internal
* Algorithm finding all the cycles starting from a given vertex.
*
* The search is only done in the subgraph induced by the starting vertex
* and the vertices with an index higher than the starting vertex.
*/
template <
typename Graph,
typename Visitor,
typename VertexIndexMap,
typename Stack,
typename ClosedMatrix,
typename GetAdjacentVertices
>
struct hawick_circuits_from {
private:
typedef graph_traits<Graph> Traits;
typedef typename Traits::vertex_descriptor Vertex;
typedef typename Traits::edge_descriptor Edge;
typedef typename Traits::vertices_size_type VerticesSize;
typedef typename property_traits<VertexIndexMap>::value_type VertexIndex;
typedef typename result_of<
GetAdjacentVertices(Vertex, Graph const&)
>::type AdjacentVertices;
typedef typename range_iterator<AdjacentVertices const>::type AdjacencyIterator;
// The one_bit_color_map starts all white, i.e. not blocked.
// Since we make that assumption (I looked at the implementation, but
// I can't find anything that documents this behavior), we're gonna
// assert it in the constructor.
typedef one_bit_color_map<VertexIndexMap> BlockedMap;
typedef typename property_traits<BlockedMap>::value_type BlockedColor;
static BlockedColor blocked_false_color()
{ return color_traits<BlockedColor>::white(); }
static BlockedColor blocked_true_color()
{ return color_traits<BlockedColor>::black(); }
// This is used by the constructor to secure the assumption
// documented above.
bool blocked_map_starts_all_unblocked() const {
BOOST_FOREACH(Vertex v, vertices(graph_))
if (is_blocked(v))
return false;
return true;
}
// This is only used in the constructor to make sure the optimization of
// sharing data structures between iterations does not break the code.
bool all_closed_rows_are_empty() const {
BOOST_FOREACH(typename ClosedMatrix::reference row, closed_)
if (!row.empty())
return false;
return true;
}
public:
hawick_circuits_from(Graph const& graph, Visitor& visitor,
VertexIndexMap const& vim,
Stack& stack, ClosedMatrix& closed,
VerticesSize n_vertices)
: graph_(graph), visitor_(visitor), vim_(vim), stack_(stack),
closed_(closed), blocked_(n_vertices, vim_)
{
BOOST_ASSERT(blocked_map_starts_all_unblocked());
// Since sharing the data structures between iterations is
// just an optimization, it must always be equivalent to
// constructing new ones in this constructor.
BOOST_ASSERT(stack_.empty());
BOOST_ASSERT(closed_.size() == n_vertices);
BOOST_ASSERT(all_closed_rows_are_empty());
}
private:
//! @internal Return the index of a given vertex.
VertexIndex index_of(Vertex v) const {
return get(vim_, v);
}
//! @internal Return whether a vertex `v` is closed to a vertex `u`.
bool is_closed_to(Vertex u, Vertex v) const {
typedef typename ClosedMatrix::const_reference VertexList;
VertexList closed_to_u = closed_[index_of(u)];
return contains(closed_to_u, v);
}
//! @internal Close a vertex `v` to a vertex `u`.
void close_to(Vertex u, Vertex v) {
BOOST_ASSERT(!is_closed_to(u, v));
closed_[index_of(u)].push_back(v);
}
//! @internal Return whether a given vertex is blocked.
bool is_blocked(Vertex v) const {
return get(blocked_, v) == blocked_true_color();
}
//! @internal Block a given vertex.
void block(Vertex v) {
put(blocked_, v, blocked_true_color());
}
//! @internal Unblock a given vertex.
void unblock(Vertex u) {
typedef typename ClosedMatrix::reference VertexList;
put(blocked_, u, blocked_false_color());
VertexList closed_to_u = closed_[index_of(u)];
while (!closed_to_u.empty()) {
Vertex const w = closed_to_u.back();
closed_to_u.pop_back();
if (is_blocked(w))
unblock(w);
}
BOOST_ASSERT(closed_to_u.empty());
}
//! @internal Main procedure as described in the paper.
bool circuit(Vertex start, Vertex v) {
bool found_circuit = false;
stack_.push_back(v);
block(v);
// Cache some values that are used more than once in the function.
VertexIndex const index_of_start = index_of(start);
AdjacentVertices const adj_vertices = GetAdjacentVertices()(v, graph_);
AdjacencyIterator const w_end = boost::end(adj_vertices);
for (AdjacencyIterator w_it = boost::begin(adj_vertices);
w_it != w_end;
++w_it)
{
Vertex const w = *w_it;
// Since we're only looking in the subgraph induced by `start`
// and the vertices with an index higher than `start`, we skip
// any vertex that does not satisfy that.
if (index_of(w) < index_of_start)
continue;
// If the last vertex is equal to `start`, we have a circuit.
else if (w == start) {
// const_cast to ensure the visitor does not modify the stack
visitor_.cycle(const_cast<Stack const&>(stack_), graph_);
found_circuit = true;
}
// If `w` is not blocked, we continue searching further down the
// same path for a cycle with `w` in it.
else if (!is_blocked(w) && circuit(start, w))
found_circuit = true;
}
if (found_circuit)
unblock(v);
else
for (AdjacencyIterator w_it = boost::begin(adj_vertices);
w_it != w_end;
++w_it)
{
Vertex const w = *w_it;
// Like above, we skip vertices that are not in the subgraph
// we're considering.
if (index_of(w) < index_of_start)
continue;
// If `v` is not closed to `w`, we make it so.
if (!is_closed_to(w, v))
close_to(w, v);
}
BOOST_ASSERT(v == stack_.back());
stack_.pop_back();
return found_circuit;
}
public:
void operator()(Vertex start) {
circuit(start, start);
}
private:
Graph const& graph_;
Visitor& visitor_;
VertexIndexMap const& vim_;
Stack& stack_;
ClosedMatrix& closed_;
BlockedMap blocked_;
};
template <
typename GetAdjacentVertices,
typename Graph, typename Visitor, typename VertexIndexMap
>
void call_hawick_circuits(Graph const& graph,
Visitor /* by value */ visitor,
VertexIndexMap const& vertex_index_map) {
typedef graph_traits<Graph> Traits;
typedef typename Traits::vertex_descriptor Vertex;
typedef typename Traits::vertices_size_type VerticesSize;
typedef typename Traits::vertex_iterator VertexIterator;
typedef std::vector<Vertex> Stack;
typedef std::vector<std::vector<Vertex> > ClosedMatrix;
typedef hawick_circuits_from<
Graph, Visitor, VertexIndexMap, Stack, ClosedMatrix,
GetAdjacentVertices
> SubAlgorithm;
VerticesSize const n_vertices = num_vertices(graph);
Stack stack; stack.reserve(n_vertices);
ClosedMatrix closed(n_vertices);
VertexIterator start, last;
for (boost::tie(start, last) = vertices(graph); start != last; ++start) {
// Note1: The sub algorithm may NOT be reused once it has been called.
// Note2: We reuse the Stack and the ClosedMatrix (after clearing them)
// in each iteration to avoid redundant destruction and construction.
// It would be strictly equivalent to have these as member variables
// of the sub algorithm.
SubAlgorithm sub_algo(graph, visitor, vertex_index_map,
stack, closed, n_vertices);
sub_algo(*start);
stack.clear();
typename ClosedMatrix::iterator row, last_row = closed.end();
for (row = closed.begin(); row != last_row; ++row)
row->clear();
}
}
template <typename GetAdjacentVertices, typename Graph, typename Visitor>
void call_hawick_circuits(Graph const& graph, BOOST_FWD_REF(Visitor) visitor) {
call_hawick_circuits<GetAdjacentVertices>(
graph, boost::forward<Visitor>(visitor), get(vertex_index, graph)
);
}
} // end namespace hawick_circuits_detail
//! Enumerate all the elementary circuits in a directed multigraph.
template <typename Graph, typename Visitor, typename VertexIndexMap>
void hawick_circuits(BOOST_FWD_REF(Graph) graph,
BOOST_FWD_REF(Visitor) visitor,
BOOST_FWD_REF(VertexIndexMap) vertex_index_map) {
hawick_circuits_detail::call_hawick_circuits<
hawick_circuits_detail::get_all_adjacent_vertices
>(
boost::forward<Graph>(graph),
boost::forward<Visitor>(visitor),
boost::forward<VertexIndexMap>(vertex_index_map)
);
}
template <typename Graph, typename Visitor>
void hawick_circuits(BOOST_FWD_REF(Graph) graph,
BOOST_FWD_REF(Visitor) visitor) {
hawick_circuits_detail::call_hawick_circuits<
hawick_circuits_detail::get_all_adjacent_vertices
>(boost::forward<Graph>(graph), boost::forward<Visitor>(visitor));
}
/*!
* Same as `boost::hawick_circuits`, but duplicate circuits caused by parallel
* edges will not be considered. Each circuit will be considered only once.
*/
template <typename Graph, typename Visitor, typename VertexIndexMap>
void hawick_unique_circuits(BOOST_FWD_REF(Graph) graph,
BOOST_FWD_REF(Visitor) visitor,
BOOST_FWD_REF(VertexIndexMap) vertex_index_map) {
hawick_circuits_detail::call_hawick_circuits<
hawick_circuits_detail::get_unique_adjacent_vertices
>(
boost::forward<Graph>(graph),
boost::forward<Visitor>(visitor),
boost::forward<VertexIndexMap>(vertex_index_map)
);
}
template <typename Graph, typename Visitor>
void hawick_unique_circuits(BOOST_FWD_REF(Graph) graph,
BOOST_FWD_REF(Visitor) visitor) {
hawick_circuits_detail::call_hawick_circuits<
hawick_circuits_detail::get_unique_adjacent_vertices
>(boost::forward<Graph>(graph), boost::forward<Visitor>(visitor));
}
} // end namespace boost
#endif // !BOOST_GRAPH_HAWICK_CIRCUITS_HPP