graph.h File Reference

Description

Core graph class definitions and constructors.

Classes
struct	stag::edge
	A structure representing a weighted edge in a graph. More...
class	stag::LocalGraph
	An abstract class which defines methods for exploring the local neighborhood of vertices in a graph. More...
class	stag::Graph
	The core object used to represent graphs for use with the library. More...
class	stag::AdjacencyListLocalGraph
	A local graph backed by an adjacency list file on disk. More...

Functions
stag::Graph	stag::cycle_graph (StagInt n)
stag::Graph	stag::complete_graph (StagInt n)
stag::Graph	stag::barbell_graph (StagInt n)
stag::Graph	stag::star_graph (StagInt n)
stag::Graph	stag::identity_graph (StagInt n)
template<typename Scalar >
stag::Graph	stag::operator* (Scalar lhs, const stag::Graph &rhs)
template<typename Scalar >
stag::Graph	stag::operator* (const stag::Graph &lhs, Scalar rhs)
stag::Graph	stag::operator+ (const stag::Graph &lhs, const stag::Graph &rhs)

Function Documentation

cycle_graph()

stag::Graph stag::cycle_graph

(

StagInt

n

)

Construct a cycle graph on n vertices.

Parameters

n	the number of vertices in the constructed graph

Returns

a stag::Graph object representing a cycle graph

complete_graph()

stag::Graph stag::complete_graph

(

StagInt

n

)

Construct a complete graph on n vertices.

Parameters

n	the number of vertices in the constructed graph

Returns

a stag::Graph object representing a complete graph

barbell_graph()

stag::Graph stag::barbell_graph

(

StagInt

n

)

Construct a barbell graph. The barbell graph consists of 2 cliques on n vertices, connected by a single edge.

Parameters

n	the number of vertices in each of the two cliques. The returned graph will have \(2n\) vertices.

Returns

a stag::Graph object representing the barbell graph

star_graph()

stag::Graph stag::star_graph

(

StagInt

n

)

Construct a star graph. The star graph consists of one central vertex connected by an edge to n-1 outer vertices.

Parameters

n	the number of vertices in the constructed graph

Returns

a stag::Graph object representing the star graph

identity_graph()

stag::Graph stag::identity_graph

(

StagInt

n

)

Construct the 'identity graph'. The identity graph consists of \(n\) vertices, each with a self-loop of weight 1.

Both the adjacency matrix and Laplacian matrix of the identity graph are equal to the identity matrix.

Parameters

n	the number of vertices in the constructed graph

Returns

a stag::Graph object representing the identity graph

operator*() [1/2]

template<typename Scalar >

stag::Graph stag::operator*	(	Scalar	lhs,
		const stag::Graph &	rhs
	)

Multiplying a graph by a scalar is equivalent to multiplying the weight of each edge by the given value.

For example, the following code creates a complete graph with edges of weight 2.

#include <stag/graph.h>
 
int main() {
  stag::Graph myGraph = 2 * stag::complete_graph(10);
 
  return 0;
}

operator*() [2/2]

template<typename Scalar >

stag::Graph stag::operator*	(	const stag::Graph &	lhs,
		Scalar	rhs
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

operator+()

stag::Graph stag::operator+	(	const stag::Graph &	lhs,
		const stag::Graph &	rhs
	)

Adding two graphs is equivalent to adding their adjacency matrices.

The graphs must have the same number of vertices. For example, the following code adds a complete graph and a cycle graph on \(5\) vertices.

#include <stag/graph.h>
 
int main() {
    stag::Graph myGraph = stag::complete_graph(5) + stag::cycle_graph(5);
 
    return 0;
}

Exceptions

std::invalud_argument

if the graphs have different sizes.