drop Graphs.jl dependency

Author: cscherrer

Project.toml

@@ -9,7 +9,6 @@ DiffResults = "163ba53b-c6d8-5494-b064-1a9d43ac40c5"
 Distributions = "31c24e10-a181-5473-b8eb-7969acd0382f"
 FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"
 GeneralizedGenerated = "6b9d7cbe-bcb9-11e9-073f-15a7a543e2eb"
-Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"
 IRTools = "7869d1d1-7146-5819-86e3-90919afe41df"
 JuliaVariables = "b14d175d-62b4-44ba-8fb7-3064adc8c3ec"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
@@ -43,9 +42,8 @@ TupleVectors = "615932cf-77b6-4358-adcd-5b7eba981d7e"
 ArrayInterface = "3"
 DiffResults = "1"
 Distributions = "0.23, 0.24, 0.25"
-FillArrays = "0.9, 0.10, 0.11, 0.12"
+FillArrays = "0.10, 0.11, 0.12"
 GeneralizedGenerated = "0.3"
-Graphs = "0.10"
 IRTools = "0.4"
 JuliaVariables = "0.2"
 MLStyle = "0.3,0.4"
@@ -67,7 +65,7 @@ SpecialFunctions = "0.9, 0.10, 1"
 StatsBase = "0.33"
 StatsFuns = "0.9"
 SymbolicCodegen = "0.2"
-SymbolicUtils = "0.11, 0.12, 0.13"
+SymbolicUtils = "0.14, 0.15, 0.16"
 TransformVariables = "0.4"
 TupleVectors = "0.1"
 julia = "1.5"

src/core/toposort.jl

@@ -1,37 +1,34 @@
 import SimplePosets
 using SimpleGraphs: SimpleGraph, AbstractSimpleGraph, SimpleDigraph, eltype, NV, elist, in_neighbors, add_edges!, vertex2idx
 
-import Graphs
-import Graphs.simple_graph, Graphs.add_edge!, Graphs.topological_sort_by_dfs
-export convert_simple
+export toposort
+function toposort(m::Model)
+    names = toposort(poset(m).D)
+    setdiff(names, arguments(m))
+end
 
-# From https://github.com/scheinerman/SimpleGraphs.jl/blob/1396758729f95912d7f245f9c70957f4993be417/src/simple_converters.jl
-function convert_simple(G::AbstractSimpleGraph)
-    T = eltype(G)
-    n = NV(G)
-    has_dir = isa(G,SimpleDigraph)
+# Thanks to @CameronBieganek for this implementation:
+# https://discourse.julialang.org/t/lightgraphs-jl-transition/69526/52?u=cscherrer
+function toposort(g::SimpleDigraph{T}) where {T}
+    g = deepcopy(g)
+    order = T[]
+    s = collect(filter(v -> SimpleGraphs.in_deg(g, v) == 0, vlist(g)))
 
+    while !isempty(s)
+        u = pop!(s)
+        push!(order, u)
 
-    d = vertex2idx(G)
-    dinv = Dict{Int,T}()
-    for k in keys(d)
-        v = d[k]
-        dinv[v] = k
+        for v in out_neighbors(g, u)
+            delete!(g, u, v)
+            if SimpleGraphs.in_deg(g, v) == 0
+                push!(s, v)
+            end
+        end
     end
 
-    H = simple_graph(n,is_directed=has_dir)
-
-    EE = elist(G)
-    for e in EE
-        u = d[e[1]]
-        v = d[e[2]]
-        add_edge!(H,u,v)
+    if SimpleGraphs.NE(g) > 0
+        error("Graph contains cycles.")
     end
-    return (H,d,dinv)
-end
 
-export toposort
-function toposort(m::Model)
-    (g, _, names) = poset(m).D |> convert_simple
-    setdiff(map(v -> names[v], Graphs.topological_sort_by_dfs(g)), arguments(m))
+    order
 end