/NautyTraces.jl

A simple interface to the nauty/trace code to test graph isomorphism.

Primary LanguageJuliaMIT LicenseMIT

NautyTraces.jl

This package provides Julia bindings to the nauty and traces library, accessible via the nauty graph format or any SimpleGraph format.

julia> using Pkg; Pkg.add("NautyTraces"); Pkg.build("NautyTraces")

julia> using Graphs, NautyTraces

julia> g = DenseNautyGraph(10) # a graph on 10 vertices
DenseNautyGraph(Bool[0 0  0 0; 0 0  0 0;  ; 0 0  0 0; 0 0  0 0])

julia> for i=1:5 # the Petersen graph
           add_edge!(g,i,mod1(i+1,5))
           add_edge!(g,i,5+i)
           add_edge!(g,5+i,5+mod1(i+2,5))
       end

julia> result = nauty(g,automgroup=true)
(orbits: IntDisjointSets{Int64}([1, 1, 1, 1, 1, 1, 1, 1, 1, 1], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 1), group size: 120, generators: Permutations.Permutation[(1)(2)(3)(4,8)(5,6)(7)(9,10), (1)(2)(3,7)(4,9)(5,6)(8,10), (1)(2,5)(3,4)(6)(7,10)(8,9), (1,2)(3,5)(4)(6,7)(8,10)(9)])

julia> g = DenseNautyGraph(cycle_graph(10)) # a cycle
DenseNautyGraph(Bool[0 0  0 0; 0 0  0 0;  ; 1 0  0 0; 0 1  0 1])

julia> result = nauty(g,getcanon=true)
(orbits: DataStructures.IntDisjointSets{Int64}([1, 1, 1, 1, 1, 1, 1, 1, 1, 1], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 1), group size: 20, labeling: (1)(2,10,9,3)(4,6,7)(5)(8), canong)

julia> SimpleGraph(result.canong)
{10, 10} undirected simple Int64 graph

julia> collect(edges(ans)) # edges in the canonical ordering of the cycle
10-element Vector{Graphs.SimpleGraphs.SimpleEdge{Int64}}:
 Edge 1 => 2
 Edge 1 => 3
 Edge 2 => 10
 Edge 3 => 9
 Edge 4 => 5
 Edge 4 => 6
 Edge 5 => 7
 Edge 6 => 8
 Edge 7 => 9
 Edge 8 => 10