Creating Graphs

Creating Graphs

New Graphs

Create a new graph with G = UndirectedGraph() or G = UG(). The vertices of this graph may be any Julia type.

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WARNING: Problems may arise using vertices of Any type. It is better to specify a specific type for the vertices.

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A user may use G = UndirectedGraph{T}() to create a graph in which vertices are of type T. Two special cases are provided:

• IntGraph() is equivalent to UndirectedGraph{Int}(). One may also have G = IntGraph(n) which will create a graph whose vertex set is {1,2,...,n} (with no edges).
• UndirectedGraph(A) (where A is an n-by-n, zero-one, hollow, symmetric matrix) creates a graph whose vertex set is {1,2,...,n} and whose adjacency matrix is A.
• UndirectedGraph() is equivalent to UndirectedGraph{String}().
• StringGraph(file_name) builds a graph from data in a file.

Copying

Use H = deep_copy(G) to make a new graph H identical to G.

Adding/Deleting Vertices/Edges

• add!(G,v) adds a vertex v to the graph.
• add!(G,v,w) adds the edge (v,w) to the graph.
• add_edges!(G,edge_list) adds a list of edges to the graph; edge_list is a Set or Array of 2-tuples.
• delete!(G,v) deletes vertex v from the graph.
• delete!(G,v,w) deletes the edge (v,w) from the graph.

Graph Name

Optionally, a graph can be given a name using the name function:

julia> G = IntGraph(10)
UndirectedGraph{Int64} (n=10, m=0)

julia> name(G,"Fred")

julia> G
Fred (n=10, m=0)

julia> name(G)
"Fred"

Note: If the graph is modified, then it's name is erased.

julia> add!(G,1,2)
true

julia> G
UndirectedGraph{Int64} (n=10, m=1)