move BlossomV to an extension to permit GraphsMatching install on any system

Author: Krastanov

Project.toml

@@ -4,7 +4,6 @@ authors = ["JuliaGraphs"]
 version = "0.2.1"
 
 [deps]
-BlossomV = "6c721016-9dae-5d90-abf6-67daaccb2332"
 Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"
 Hungarian = "e91730f6-4275-51fb-a7a0-7064cfbd3b39"
 JuMP = "4076af6c-e467-56ae-b986-b466b2749572"
@@ -13,14 +12,20 @@ LEMONGraphs = "14b1564f-c77f-4800-9e89-efd961faef7c"
 MathOptInterface = "b8f27783-ece8-5eb3-8dc8-9495eed66fee"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 
+[weakdeps]
+BlossomV = "6c721016-9dae-5d90-abf6-67daaccb2332"
+
+[extensions]
+GraphsMatchingBlossomVExt = "BlossomV"
+
 [compat]
 BlossomV = "0.4"
 Graphs = "1.4, 1.7"
 Hungarian = "0.4, 0.6, 0.7"
 JuMP = "1"
 LEMONGraphs = "0.1.0"
 MathOptInterface = "1"
-julia = "1"
+julia = "1.10"
 
 [extras]
 Cbc = "9961bab8-2fa3-5c5a-9d89-47fab24efd76"

ext/GraphsMatchingBlossomVExt/GraphsMatchingBlossomVExt.jl

@@ -0,0 +1,26 @@
+module GraphsMatchingBlossomVExt
+
+using Graphs
+using GraphsMatching
+import BlossomV
+
+function GraphsMatching.minimum_weight_perfect_matching(g::Graph, w::Dict{E,U}, ::BlossomVAlgorithm) where {U<:Integer,E<:Edge}
+    m = BlossomV.Matching(nv(g))
+    for (e, c) in w
+        BlossomV.add_edge(m, src(e) - 1, dst(e) - 1, c)
+    end
+    BlossomV.solve(m)
+
+    mate = fill(-1, nv(g))
+    totweight = zero(U)
+    for i in 1:nv(g)
+        j = BlossomV.get_match(m, i - 1) + 1
+        mate[i] = j <= 0 ? -1 : j
+        if i < j
+            totweight += w[Edge(i, j)]
+        end
+    end
+    return MatchingResult(totweight, mate)
+end
+
+end

src/GraphsMatching.jl

@@ -7,7 +7,6 @@ using SparseArrays: spzeros
 using JuMP
 using MathOptInterface
 const MOI = MathOptInterface
-import BlossomV
 import LEMONGraphs
 using Hungarian
 
@@ -21,6 +20,16 @@ export MatchingResult,
     BlossomVAlgorithm,
     LEMONMWPMAlgorithm
 
+function __init__()
+    if isdefined(Base.Experimental, :register_error_hint)
+        Base.Experimental.register_error_hint(MethodError) do io, exc, argtypes, kwargs
+            if BlossomVAlgorithm in argtypes
+                print(io,"""\nPlease first import `BlossomV` to make BlossomV-based matching available.""")
+            end
+        end
+    end
+end
+
 """
     struct MatchingResult{U}
         weight::U

src/minimum_weight_perfect_matching.jl

@@ -77,7 +77,7 @@ function minimum_weight_perfect_matching(
 end
 
 function minimum_weight_perfect_matching(
-    g::Graph, w::Dict{E,U}, cutoff, algorithm::AbstractMinimumWeightPerfectMatchingAlgorithm=LEMONMWPMAlgorithm(); kws...
+    g::Graph, w::Dict{E,U}, cutoff::Real, algorithm::AbstractMinimumWeightPerfectMatchingAlgorithm=LEMONMWPMAlgorithm(); kws...
 ) where {U<:Real,E<:Edge}
     wnew = Dict{E,U}()
     for (e, c) in w
@@ -111,25 +111,6 @@ function minimum_weight_perfect_matching(
     return MatchingResult(weight, match.mate)
 end
 
-function minimum_weight_perfect_matching(g::Graph, w::Dict{E,U}, ::BlossomVAlgorithm) where {U<:Integer,E<:Edge}
-    m = BlossomV.Matching(nv(g))
-    for (e, c) in w
-        BlossomV.add_edge(m, src(e) - 1, dst(e) - 1, c)
-    end
-    BlossomV.solve(m)
-
-    mate = fill(-1, nv(g))
-    totweight = zero(U)
-    for i in 1:nv(g)
-        j = BlossomV.get_match(m, i - 1) + 1
-        mate[i] = j <= 0 ? -1 : j
-        if i < j
-            totweight += w[Edge(i, j)]
-        end
-    end
-    return MatchingResult(totweight, mate)
-end
-
 function minimum_weight_perfect_matching(g::Graph, w::Dict{E,U}, ::LEMONMWPMAlgorithm) where {U<:Integer,E<:Edge}
     max = 2*abs(maximum(values(w)))
     weights = [-get(w, e, max) for e in edges(g)]

test/Project.toml

@@ -0,0 +1,11 @@
+[deps]
+BlossomV = "6c721016-9dae-5d90-abf6-67daaccb2332"
+Cbc = "9961bab8-2fa3-5c5a-9d89-47fab24efd76"
+Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"
+Hungarian = "e91730f6-4275-51fb-a7a0-7064cfbd3b39"
+JuMP = "4076af6c-e467-56ae-b986-b466b2749572"
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+LEMONGraphs = "14b1564f-c77f-4800-9e89-efd961faef7c"
+MathOptInterface = "b8f27783-ece8-5eb3-8dc8-9495eed66fee"
+SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

test/runtests.jl

@@ -5,6 +5,8 @@ using Cbc
 using JuMP
 using LinearAlgebra: I
 
+import BlossomV # to test the extension
+
 @testset "GraphsMatching" begin
 
     @testset "maximum_weight_matching_reduction" begin