StackOverflow

[jtrakk]

This code has a stack overflow.

julia> Buchheim()(random_regular_digraph(20, 10))
ERROR: LoadError: StackOverflowError:
Stacktrace:
 [1] findall(testf::Function, A::Vector{Int64})
   @ Base ./array.jl:2257
 [2] parent
   @ ~/.julia/packages/NetworkLayout/ObipC/src/buchheim.jl:88 [inlined]
 [3] first_walk(v::Int64, t::NetworkLayout.Tree{Vector{Vector{Int64}}, Vector{GeometryBasics.Point2{Float64}}, Vector{Float64}})
   @ NetworkLayout ~/.julia/packages/NetworkLayout/ObipC/src/buchheim.jl:101
 [4] first_walk(v::Int64, t::NetworkLayout.Tree{Vector{Vector{Int64}}, Vector{GeometryBasics.Point2{Float64}}, Vector{Float64}}) (repeats 14390 times)
   @ NetworkLayout ~/.julia/packages/NetworkLayout/ObipC/src/buchheim.jl:116
 [5] layout(para::NetworkLayout.Buchheim{Float64, Float64}, adj_list::Vector{Vector{Int64}})
   @ NetworkLayout ~/.julia/packages/NetworkLayout/ObipC/src/buchheim.jl:80
 [6] layout(para::NetworkLayout.Buchheim{Float64, Float64}, adj_matrix::SparseArrays.SparseMatrixCSC{Int64, Int64})
   @ NetworkLayout ~/.julia/packages/NetworkLayout/ObipC/src/buchheim.jl:69
 [7] layout
   @ ~/.julia/packages/NetworkLayout/ObipC/src/NetworkLayout.jl:99 [inlined]
 [8] (::NetworkLayout.Buchheim{Float64, Float64})(adj_matrix::Graphs.SimpleGraphs.SimpleDiGraph{Int64})
   @ NetworkLayout ~/.julia/packages/NetworkLayout/ObipC/src/NetworkLayout.jl:34
 [9] top-level scope

[hexaeder]

Yeah similar to #7, this is because Buchheim algorithm works for rooted trees only. A regular digraph isn't a tree at all so the code should error but not with stack overflow. This will be closed by #34, thanks for reminding me of this PR!