Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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C++ Boost

is_bipartite

// Version with a colormap to retrieve the bipartition
template <typename Graph, typename IndexMap, typename PartitionMap>
bool is_bipartite (const Graph& graph, const IndexMap index_map, PartitionMap partition_map)

template <typename Graph, typename IndexMap>
bool is_bipartite (const Graph& graph, const IndexMap index_map)

// Version which uses the internal index map
template <typename Graph>
bool is_bipartite (const Graph& graph);

The is_bipartite() functions tests a given graph for bipartiteness using a DFS-based coloring approach.

An undirected graph is bipartite if one can partition its set of vertices into two sets "left" and "right", such that each edge goes from either side to the other. Obviously, a two-coloring of the graph is exactly the same as a two-partition. is_bipartite() tests whether such a two-coloring is possible and can return it in a given property map.

The bipartition is recorded in the color map partition_map, which will contain a two-coloring of the graph, i.e. an assignment of black and white to the vertices such that no edge is monochromatic. The predicate whether the graph is bipartite is the return value of the function.

Where Defined

boost/graph/bipartite.hpp

Parameters

IN: const Graph& graph

An undirected graph. The graph type must be a model of Vertex List Graph and Incidence Graph.

IN: const IndexMap index_map

This maps each vertex to an integer in the range [0, num_vertices(graph)). The type VertexIndexMap must be a model of Readable Property Map. The value type of the map must be an integer type. The vertex descriptor type of the graph needs to be usable as the key type of the map.

OUT: PartitionMap partition_map

The algorithm tests whether the graph is bipartite and assigns each vertex either a white or a black color, according to the partition. The PartitionMap type must be a model of Readable Property Map and Writable Property Map The value type must model ColorValue.

Complexity

The time complexity for the algorithm is O(V + E).

See Also

find_odd_cycle()

Example

The file examples/bipartite.cpp contains an example of testing an undirected graph for bipartiteness.


Copyright © 2010 Matthias Walter (xammy@xammy.homelinux.net)