Fix a bug related to ConfigsMax (#62)

* Fix a bug related to ConfigsMax

* fix test and 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 = "1.3.2"
+version = "1.3.3"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"

src/bounding.jl

@@ -14,7 +14,11 @@ The backward rule for tropical einsum.
 * `size_dict` is a key-value map from tensor label to dimension size.
 """
 function backward_tropical(mode, ixs, @nospecialize(xs::Tuple), iy, @nospecialize(y), @nospecialize(ymask), size_dict)
-    y .= inv.(y) .* ymask
+    # remove float to improve the stability of the algorithm
+    removeinf(x::CountingTropical{<:AbstractFloat}) = isinf(x.n) ? typeof(x)(prevfloat(x.n), x.c) : x
+    removeinf(x::Tropical{<:AbstractFloat}) = isinf(x.n) ? typeof(x)(prevfloat(x.n)) : x
+    removeinf(x) = x
+    y .= removeinf.(inv.(y) .* ymask)
     masks = []
     for i=1:length(ixs)
         nixs = OMEinsum._insertat(ixs, i, iy)

src/networks/IndependentSet.jl

@@ -60,10 +60,11 @@ 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([
+    tensors = select_dims([
             add_labels!(Array{T}[misv(_pow.(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))
+    return tensors
 end
 
 function misb(::Type{T}, n::Integer=2) where T

test/configurations.jl

@@ -58,4 +58,22 @@ end
             @test all(x->count_ones(x)==(i-1), s.data)
         end
     end
+end
+
+@testset "configs bug fix" begin
+    subgraph = let
+        g = SimpleGraph(5)
+        vertices = "cdefg"
+        for (w, v) in ["cd", "ce", "cf", "de", "ef", "fg"]
+            add_edge!(g, findfirst(==(w), vertices), findfirst(==(v), vertices))
+        end
+        g
+    end
+    problem = IndependentSet(subgraph, openvertices=[1,4,5])
+    res1 = solve(problem, SizeMax(), T=Float64)
+    @test res1 == Tropical.(reshape([1, 1, 2, -Inf, 2, 2, -Inf, -Inf], 2, 2, 2))
+    res2 = solve(problem, CountingMax(); T=Float64)
+    res3 = solve(problem, ConfigsMax(; bounded=true); T=Float64)
+    @test getfield.(res2, :n) == getfield.(res1, :n)
+    @test getfield.(res3, :n) == getfield.(res1, :n)
 end