fix empty graph (#48)

* fix empty graph

* bump version

Author: GiggleLiu

Project.toml

@@ -1,7 +1,7 @@
 name = "GenericTensorNetworks"
 uuid = "3521c873-ad32-4bb4-b63d-f4f178f42b49"
 authors = ["GiggleLiu <cacate0129@gmail.com> and contributors"]
-version = "1.0.5"
+version = "1.0.6"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"

src/networks/Coloring.jl

@@ -42,9 +42,10 @@ fixedvertices(gp::Coloring) = gp.fixedvertices
 
 function generate_tensors(x::T, c::Coloring{K}) where {K,T}
     ixs = getixsv(c.code)
-    return select_dims(vcat(
-        add_labels!([coloringv(T, K) for i=1:nv(c.graph)], ixs[1:nv(c.graph)], labels(c)), [coloringb(x, K) .^ get_weights(c, i) for i=1:ne(c.graph)]
-    ), ixs, fixedvertices(c))
+    return select_dims([
+        add_labels!(Array{T}[coloringv(T, K) for i=1:nv(c.graph)], ixs[1:nv(c.graph)], labels(c))...,
+        Array{T}[coloringb(x, K) .^ get_weights(c, i) for i=1:ne(c.graph)]...
+    ], ixs, fixedvertices(c))
 end
 
 # coloring bond tensor

src/networks/IndependentSet.jl

@@ -56,9 +56,10 @@ function generate_tensors(x::T, gp::IndependentSet) where T
     nv(gp.graph) == 0 && return []
     ixs = getixsv(gp.code)
     # we only add labels at vertex tensors
-    return select_dims(vcat(add_labels!([misv(Ref(x) .^ get_weights(gp, i)) for i=1:nv(gp.graph)], ixs[1:nv(gp.graph)], labels(gp)),
-            [misb(T, length(ix)) for ix in ixs[nv(gp.graph)+1:end]] # if n!=2, it corresponds to set packing problem.
-    ), ixs, fixedvertices(gp))
+    return select_dims([
+            add_labels!(Array{T}[misv(Ref(x) .^ get_weights(gp, i)) for i=1:nv(gp.graph)], ixs[1:nv(gp.graph)], labels(gp))...,
+            Array{T}[misb(T, length(ix)) for ix in ixs[nv(gp.graph)+1:end]]... # if n!=2, it corresponds to set packing problem.
+    ], ixs, fixedvertices(gp))
 end
 
 function misb(::Type{T}, n::Integer=2) where T

src/networks/Matching.jl

@@ -41,9 +41,9 @@ labels(gp::Matching) = getindex.(terms(gp))
 fixedvertices(gp::Matching) = gp.fixedvertices
 
 function generate_tensors(x::T, m::Matching) where T
-    ne(m.graph) == 0 && return []
+    ne(m.graph) == 0 && return Array{T}[]
     ixs = getixsv(m.code)
-    tensors = AbstractArray{T}[]
+    tensors = Array{T}[]
     for i=1:length(ixs)
         ix = ixs[i]
         if i<=ne(m.graph)

src/networks/OpenPitMining.jl

@@ -98,8 +98,10 @@ function generate_tensors(x::T, gp::OpenPitMining) where T
     nblocks == 0 && return []
     ixs = getixsv(gp.code)
     # we only add labels at vertex tensors
-    return select_dims(vcat(add_labels!([Ref(x) .^ get_weights(gp, i) for i=1:nblocks], ixs[1:nblocks], labels(gp)),
-            [mining_tensor(T) for ix in ixs[nblocks+1:end]]), ixs, fixedvertices(gp)
+    return select_dims([
+        add_labels!(Array{T}[Ref(x) .^ get_weights(gp, i) for i=1:nblocks], ixs[1:nblocks], labels(gp))...,
+        Array{T}[mining_tensor(T) for ix in ixs[nblocks+1:end]]...
+        ], ixs, fixedvertices(gp)
     )
 end
 

src/networks/PaintShop.jl

@@ -57,9 +57,8 @@ function PaintShop(sequence::AbstractVector{T}; openvertices=(), fixedvertices=D
     @assert all(l->count(==(l), sequence)==2, sequence)
     n = length(sequence)
     isfirst = [findfirst(==(sequence[i]), sequence) == i for i=1:n]
-    rawcode = EinCode(vcat(
+    rawcode = EinCode(
                 [[sequence[i], sequence[i+1]] for i=1:n-1], # labels for edge tensors
-                ),
                 collect(T, openvertices))
     PaintShop(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), sequence, isfirst, Dict{T,Int}(fixedvertices))
 end
@@ -73,7 +72,7 @@ fixedvertices(gp::PaintShop) = gp.fixedvertices
 function generate_tensors(x::T, c::PaintShop) where T
     ixs = getixsv(c.code)
     tensors = [paintshop_bond_tensor((Ref(x) .^ get_weights(c, i))...) for i=1:length(ixs)]
-    return select_dims(add_labels!([flip_labels(tensors[i], c.isfirst[i], c.isfirst[i+1]) for i=1:length(ixs)], ixs, labels(c)), ixs, fixedvertices(c))
+    return select_dims(add_labels!(Array{T}[flip_labels(tensors[i], c.isfirst[i], c.isfirst[i+1]) for i=1:length(ixs)], ixs, labels(c)), ixs, fixedvertices(c))
 end
 
 function paintshop_bond_tensor(a::T, b::T) where T

src/networks/SetCovering.jl

@@ -81,8 +81,9 @@ function generate_tensors(x::T, gp::SetCovering) where T
     nsets == 0 && return []
     ixs = getixsv(gp.code)
     # we only add labels at vertex tensors
-    return select_dims(vcat(add_labels!([misv(Ref(x) .^ get_weights(gp, i)) for i=1:nsets], ixs[1:nsets], labels(gp)),
-            [cover_tensor(T, ix) for ix in ixs[nsets+1:end]]), ixs, fixedvertices(gp)
+    return select_dims([
+        add_labels!(Array{T}[misv(Ref(x) .^ get_weights(gp, i)) for i=1:nsets], ixs[1:nsets], labels(gp))...,
+            Array{T}[cover_tensor(T, ix) for ix in ixs[nsets+1:end]]...], ixs, fixedvertices(gp)
     )
 end
 

src/networks/SetPacking.jl

@@ -54,8 +54,9 @@ function generate_tensors(x::T, gp::SetPacking) where T
     length(gp.sets) == 0 && return []
     ixs = getixsv(gp.code)
     # we only add labels at vertex tensors
-    return select_dims(vcat(add_labels!([misv(Ref(x) .^ get_weights(gp, i)) for i=1:length(gp.sets)], ixs[1:length(gp.sets)], labels(gp)),
-            [misb(T, length(ix)) for ix in ixs[length(gp.sets)+1:end]]), ixs, fixedvertices(gp),
+    return select_dims([
+        add_labels!(Array{T}[misv(Ref(x) .^ get_weights(gp, i)) for i=1:length(gp.sets)], ixs[1:length(gp.sets)], labels(gp))...,
+        Array{T}[misb(T, length(ix)) for ix in ixs[length(gp.sets)+1:end]]...], ixs, fixedvertices(gp),
     )
 end
 

test/networks/Coloring.jl

@@ -25,4 +25,10 @@ end
     @test solve(problem, SizeMax())[].n == 30
     res = solve(problem, SingleConfigMax())[].c.data
     @test is_vertex_coloring(g, res)
+end
+
+@testset "empty graph" begin
+    g = SimpleGraph(4)
+    pb = Coloring{3}(g)
+    @test solve(pb, SizeMax()) !== 4
 end

test/networks/DominatingSet.jl

@@ -24,4 +24,10 @@ end
     for config in configs
         @test is_dominating_set(g, config)
     end
+end
+
+@testset "empty graph" begin
+    g = SimpleGraph(4)
+    pb = MaximalIS(g)
+    @test solve(pb, SizeMax()) !== 4
 end