added convenience constructors to drop weights. (#50)

Author: willow-ahrens

src/simpleweighteddigraph.jl

@@ -71,6 +71,8 @@ function SimpleWeightedDiGraph(i::AbstractVector{T}, j::AbstractVector{T}, v::Ab
     SimpleWeightedDiGraph{T, U}(sparse(j, i, v, m, m, combine); permute=false)
 end
 
+LightGraphs.SimpleDiGraph(g::SimpleWeightedDiGraph) = SimpleDiGraph(g.weights)
+
 edgetype(::SimpleWeightedDiGraph{T, U}) where T<:Integer where U<:Real = SimpleWeightedGraphEdge{T,U}
 
 edges(g::SimpleWeightedDiGraph) = (SimpleWeightedEdge(x[2], x[1], x[3]) for x in zip(findnz(g.weights)...))

src/simpleweightedgraph.jl

@@ -87,6 +87,8 @@ function SimpleWeightedGraph(i::AbstractVector{T}, j::AbstractVector{T}, v::Abst
     SimpleWeightedGraph{T, U}(s)
 end
 
+LightGraphs.SimpleGraph(g::SimpleWeightedGraph) = SimpleGraph(g.weights)
+
 edgetype(::SimpleWeightedGraph{T, U}) where T<:Integer where U<:Real= SimpleWeightedGraphEdge{T,U}
 
 edges(g::SimpleWeightedGraph) = (SimpleWeightedEdge(x[1], x[2], x[3]) for x in zip(findnz(triu(g.weights))...))

test/simpleweightedgraph.jl

@@ -219,4 +219,7 @@ using SimpleWeightedGraphs
     @test s.weights[1,2] == 1
     @test s.weights[2,1] == 2
 
+    @test SimpleDiGraph(SimpleWeightedDiGraph(CycleGraph(4))) == SimpleDiGraph(CycleGraph(4))
+    @test SimpleGraph(SimpleWeightedGraph(PathGraph(5))) == PathGraph(5)
+
 end