MetaGraphs load and save

Question

How can I save and load a MetaGraph object from LightGraphs, and MetaGraphs, so that if I load the metagraph I still have the metadata? Right now I have a metagraph mg that I save using:

LightGraphs.savegraph("net.lg", mg)

But trying to reload it :

reloaded = LightGraphs.loadgraph("net.lg")

gives me the following:

BoundsError: attempt to access 2-element Array{SubString{String},1} at index [3]

Is there anyway to read in the metagraphs in the MetaGaphs package?

Answer 1

We support MetaGraphs persistence using a JLD format provided by JLD2.jl:

using LightGraphs, MetaGraphs
julia> g = Graph(10,20)
{10, 20} undirected simple Int64 graph

julia> mg = MetaGraph(g)
{10, 20} undirected Int64 metagraph with Float64 weights defined by :weight (default weight 1.0)

julia> savegraph("foo.mg", mg)
1

julia> mg2 = loadgraph("foo.mg", MGFormat())
{10, 20} undirected Int64 metagraph with Float64 weights defined by :weight (default weight 1.0)

julia> mg2 == mg
true

Note that you need to specify MGFormat() in the loadgraph, otherwise LightGraphs won't know what type of graph you're trying to load.