Merge branch 'JuliaGraphs:master' into master

Project.toml

@@ -1,6 +1,6 @@
 name = "Graphs"
 uuid = "86223c79-3864-5bf0-83f7-82e725a168b6"
-version = "1.7.3"
+version = "1.7.4"
 
 [deps]
 ArnoldiMethod = "ec485272-7323-5ecc-a04f-4719b315124d"

src/SimpleGraphs/generators/randgraphs.jl

@@ -27,7 +27,7 @@ function SimpleGraph{T}(
     maxe = div(Int(nv) * (nv - 1), 2)
     @assert(ne <= maxe, "Maximum number of edges for this graph is $maxe")
     rng = rng_from_rng_or_seed(rng, seed)
-    ne > div((2 * maxe), 3)  && return complement(SimpleGraph(tnv, maxe - ne, rng=rng, seed=seed))
+    ne > div((2 * maxe), 3)  && return complement(SimpleGraph(tnv, maxe - ne, rng=rng))
 
     g = SimpleGraph(tnv)
 
@@ -70,7 +70,7 @@ function SimpleDiGraph{T}(
     maxe = Int(nv) * (nv - 1)
     @assert(ne <= maxe, "Maximum number of edges for this graph is $maxe")
     rng = rng_from_rng_or_seed(rng, seed)
-    ne > div((2 * maxe), 3) && return complement(SimpleDiGraph{T}(tnv, maxe - ne; rng=rng, seed=seed))
+    ne > div((2 * maxe), 3) && return complement(SimpleDiGraph{T}(tnv, maxe - ne; rng=rng))
     g = SimpleDiGraph(tnv)
     while g.ne < ne
         source = rand(rng, one(T):tnv)
@@ -262,7 +262,7 @@ where each vertex has exacly `div(k, 2)` neighbors on each side (i.e., `k` or
    connected to some vertex `d`, chosen uniformly at random from the entire
    graph, excluding `s` and its neighbors. (Note that `t` is a valid candidate.)
 
-For `β = 1`, the graph will remain a 1-lattice, and for `β = 0`, all edges will
+For `β = 0`, the graph will remain a 1-lattice, and for `β = 1`, all edges will
 be rewired randomly.
 
 ### Optional Arguments
@@ -789,7 +789,7 @@ function random_regular_graph(
     end
     rng = rng_from_rng_or_seed(rng, seed)
     if (k > n / 2) && iseven(n * (n - k - 1))
-        return complement(random_regular_graph(n, n - k - 1; rng=rng, seed=seed))
+        return complement(random_regular_graph(n, n - k - 1; rng=rng))
     end
 
     edges = _try_creation(n, k, rng)
@@ -876,7 +876,7 @@ function random_regular_digraph(
     end
     rng = rng_from_rng_or_seed(rng, seed)
     if (k > n / 2) && iseven(n * (n - k - 1))
-        return complement(random_regular_digraph(n, n - k - 1; dir=dir, rng=rng, seed=seed))
+        return complement(random_regular_digraph(n, n - k - 1; dir=dir, rng=rng))
     end
     cs = collect(2:n)
     i = 1
@@ -962,7 +962,7 @@ function stochastic_block_model(
 
             m = a == b ? div(n[a] * (n[a] - 1), 2) : n[a] * n[b]
             p = a == b ? n[a] * c[a, b] / (2m) : n[a] * c[a, b] / m
-            nedg = randbn(m, p; rng=rng, seed=seed)
+            nedg = randbn(m, p; rng=rng)
             rb = (cum[b] + 1):cum[b + 1]
             i = 0
             while i < nedg

src/core.jl

@@ -275,7 +275,7 @@ julia> all_neighbors(g, 3)
 2-element Array{Int64,1}:
  1
  2
- ```
+```
 """
 function all_neighbors end
 @traitfn all_neighbors(g::::IsDirected, v::Integer) =

src/traversals/dfs.jl

@@ -7,10 +7,29 @@
 Return `true` if graph `g` contains a cycle.
 
 ### Implementation Notes
-Uses DFS.
+The algorithm uses a DFS. Self-loops are counted as cycles.
 """
 function is_cyclic end
-@traitfn is_cyclic(g::::(!IsDirected)) = ne(g) > 0
+@enum Vertex_state unvisited visited
+@traitfn function is_cyclic(g::AG::(!IsDirected)) where {T, AG<:AbstractGraph{T}}
+    visited = falses(nv(g)) 
+    for v in vertices(g)
+        visited[v] && continue
+        visited[v] = true
+        S = [(v,v)] 
+        while !isempty(S)
+            parent, w = pop!(S)
+            for u in neighbors(g, w)
+                u == w && return true # self-loop
+                u == parent && continue
+                visited[u] && return true
+                visited[u] = true
+                push!(S, (w, u))
+            end
+        end
+    end
+    return false
+end
 # see https://github.com/mauro3/SimpleTraits.jl/issues/47#issuecomment-327880153 for syntax
 @traitfn function is_cyclic(g::AG::IsDirected) where {T, AG<:AbstractGraph{T}}
     vcolor = zeros(UInt8, nv(g))

test/simplegraphs/generators/randgraphs.jl

@@ -47,6 +47,11 @@
         @test erdos_renyi(5, 1.0, is_directed=true, rng=rng) == complete_digraph(5)
         @test erdos_renyi(5, 2.1, rng=rng) == complete_graph(5)
         @test erdos_renyi(5, 2.1, is_directed=true, rng=rng) == complete_digraph(5)
+
+        # issue #173
+        er = erdos_renyi(4, 6, seed=1)
+        @test nv(er) == 4
+        @test ne(er) == 6
     end
 
     @testset "expected degree" begin

test/traversals/dfs.jl

@@ -1,9 +1,15 @@
 @testset "DFS" begin
-
+  gnodes_directed=SimpleDiGraph(4)
+  gnodes_undirected=SimpleGraph(4)
+  gloop_directed=SimpleDiGraph(1)
+  add_edge!(gloop_directed, 1, 1);
+  gloop_undirected=SimpleGraph(1)
+  add_edge!(gloop_undirected, 1, 1);
   g5 = SimpleDiGraph(4)
   add_edge!(g5, 1, 2); add_edge!(g5, 2, 3); add_edge!(g5, 1, 3); add_edge!(g5, 3, 4)
   gx = cycle_digraph(3)
-
+  gcyclic = SimpleGraph([0 1 1 0 0; 1 0 1 0 0; 1 1 0 0 0; 0 0 0 0 1; 0 0 0 1 0])
+  gtree = SimpleGraph([0 1 1 1 0 0 0; 1 0 0 0 0 0 0; 1 0 0 0 0 0 0; 1 0 0 0 1 1 1; 0 0 0 1 0 0 0; 0 0 0 1 0 0 0; 0 0 0 1 0 0 0])
   @testset "dfs_tree" begin
     for g in testdigraphs(g5)
       z = @inferred(dfs_tree(g, 1))
@@ -26,8 +32,29 @@
 
   @testset "is_cyclic" begin
     for g in testgraphs(path_graph(2))
+      @test !@inferred(is_cyclic(g))
+      @test !@inferred(is_cyclic(zero(g)))
+    end
+    for g in testgraphs(gcyclic)
+      @test @inferred(is_cyclic(g))
+    end
+    for g in testgraphs(gtree)
+      @test !@inferred(is_cyclic(g))
+    end
+    for g in testgraphs(g5)
+      @test !@inferred(is_cyclic(g))
+    end
+    for g in testgraphs(gnodes_directed)
+      @test !@inferred(is_cyclic(g))
+    end
+    for g in testgraphs(gnodes_undirected)
+      @test !@inferred(is_cyclic(g))
+    end
+    for g in testgraphs(gloop_directed)
+      @test @inferred(is_cyclic(g))
+    end
+    for g in testgraphs(gloop_undirected)
       @test @inferred(is_cyclic(g))
-      @test @inferred(!is_cyclic(zero(g)))
     end
   end