slightly improved docs for graphs (#5171)

Author: micjoswig

docs/src/Combinatorics/graphs.md

@@ -54,16 +54,32 @@ label!
 ```
 
 ## Auxiliary functions
+
+### Degrees
+```@docs
+degree(g::Graph, v::Int)
+indegree(g::Graph{Directed}, v::Int)
+outdegree(g::Graph{Directed}, v::Int)
+```
+
+### Connectivity
+```@docs
+is_connected(g::Graph{Undirected})
+connected_components(g::Graph{Undirected})
+connectivity(g::Graph{Undirected})
+is_weakly_connected(g::Graph{Directed})
+is_strongly_connected(g::Graph{Directed})
+weakly_connected_components(g::Graph{Directed})
+diameter(g::Graph{T}) where {T <: Union{Directed, Undirected}}
+```
+
+### Others
 ```@docs
 adjacency_matrix(g::Graph)
 all_neighbors(g::Graph{T}, v::Int64) where {T <: Union{Directed, Undirected}}
 automorphism_group_generators(g::Graph{T}) where {T <: Union{Directed, Undirected}}
-connectivity(g::Graph{Undirected})
 complete_graph(n::Int64)
 complete_bipartite_graph(n::Int64, m::Int64)
-degree(g::Graph, v::Int)
-indegree(g::Graph{Directed}, v::Int)
-outdegree(g::Graph{Directed}, v::Int)
 vertices(g::Graph{T}) where {T <: Union{Directed, Undirected}}
 edges(g::Graph{T}) where {T <: Union{Directed, Undirected}}
 has_edge(g::Graph{T}, source::Int64, target::Int64) where {T <: Union{Directed, Undirected}}

src/Combinatorics/Graphs/functions.jl

@@ -984,6 +984,22 @@ true
 """
 is_connected(g::Graph{Undirected}) = Polymake.call_function(:graph, :is_connected, pm_object(g))::Bool
 
+@doc raw"""
+    connected_components(g::Graph{Undirected})
+
+Return the connected components of an undirected graph `g`.
+
+# Examples
+```jldoctest
+julia> g = Graph{Undirected}(2);
+
+julia> add_edge!(g, 1, 2);
+
+julia> connected_components(g)
+1-element Vector{Vector{Int64}}:
+ [1, 2]
+```
+"""
 function connected_components(g::Graph{Undirected})
     im = Polymake.call_function(:graph, :connected_components, pm_object(g))::IncidenceMatrix
     return [Vector(Polymake.row(im,i)) for i in 1:Polymake.nrows(im)]