diff --git a/src/networks/Coloring.jl b/src/networks/Coloring.jl
index 09f180c6..24dd3850 100644
--- a/src/networks/Coloring.jl
+++ b/src/networks/Coloring.jl
@@ -31,7 +31,7 @@ function Coloring{K}(g::SimpleGraph; weights=NoWeight(), openvertices=(), fixedv
     rawcode = EinCode(([[i] for i in Graphs.vertices(g)]..., # labels for vertex tensors
                        [[minmax(e.src,e.dst)...] for e in Graphs.edges(g)]...), collect(Int, openvertices))  # labels for edge tensors
     code = _optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier)
-    Coloring{K}(code, g, weights, fixedvertices)
+    Coloring{K}(code, g, weights, Dict{Int,Int}(fixedvertices))
 end
 
 flavors(::Type{<:Coloring{K}}) where K = collect(0:K-1)
@@ -69,4 +69,4 @@ function is_vertex_coloring(graph::SimpleGraph, config)
         config[e.src] == config[e.dst] && return false
     end
     return true
-end
\ No newline at end of file
+end
diff --git a/src/networks/DominatingSet.jl b/src/networks/DominatingSet.jl
index f234e9f8..fd89ea6d 100644
--- a/src/networks/DominatingSet.jl
+++ b/src/networks/DominatingSet.jl
@@ -28,7 +28,7 @@ end
 function DominatingSet(g::SimpleGraph; weights=NoWeight(), openvertices=(), fixedvertices=Dict{Int,Int}(), optimizer=GreedyMethod(), simplifier=nothing)
     @assert weights isa NoWeight || length(weights) == nv(g)
     rawcode = EinCode(([[Graphs.neighbors(g, v)..., v] for v in Graphs.vertices(g)]...,), collect(Int, openvertices))
-    DominatingSet(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), g, weights, fixedvertices)
+    DominatingSet(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), g, weights, Dict{Int,Int}(fixedvertices))
 end
 
 flavors(::Type{<:DominatingSet}) = [0, 1]
diff --git a/src/networks/IndependentSet.jl b/src/networks/IndependentSet.jl
index 5e6112c3..a8b6c251 100644
--- a/src/networks/IndependentSet.jl
+++ b/src/networks/IndependentSet.jl
@@ -42,7 +42,7 @@ function IndependentSet(g::SimpleGraph; weights=NoWeight(), openvertices=(), fix
     rawcode = EinCode([[[i] for i in Graphs.vertices(g)]..., # labels for vertex tensors
                        [[minmax(e.src,e.dst)...] for e in Graphs.edges(g)]...], collect(Int, openvertices))  # labels for edge tensors
     code = _optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier)
-    IndependentSet(code, g, weights, fixedvertices)
+    IndependentSet(code, g, weights, Dict{Int,Int}(fixedvertices))
 end
 
 flavors(::Type{<:IndependentSet}) = [0, 1]
diff --git a/src/networks/Matching.jl b/src/networks/Matching.jl
index 91e653a5..ab71a86b 100644
--- a/src/networks/Matching.jl
+++ b/src/networks/Matching.jl
@@ -22,16 +22,16 @@ struct Matching{CT<:AbstractEinsum, WT<:Union{NoWeight,Vector}} <: GraphProblem
     code::CT
     graph::SimpleGraph{Int}
     weights::WT
-    fixedvertices::Dict{Int,Int}
+    fixedvertices::Dict{Tuple{Int,Int},Int}
 end
 
-function Matching(g::SimpleGraph; weights=NoWeight(), openvertices=(),fixedvertices=Dict{Int,Int}(), optimizer=GreedyMethod(), simplifier=nothing)
+function Matching(g::SimpleGraph; weights=NoWeight(), openvertices=(),fixedvertices=Dict{Tuple{Int,Int},Int}(), optimizer=GreedyMethod(), simplifier=nothing)
     @assert weights isa NoWeight || length(weights) == ne(g)
     edges = [minmax(e.src,e.dst) for e in Graphs.edges(g)]
     rawcode = EinCode(vcat([[s] for s in edges], # labels for edge tensors
                 [[minmax(i,j) for j in neighbors(g, i)] for i in Graphs.vertices(g)]),
                 collect(Tuple{Int,Int}, openvertices))
-    Matching(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), g, weights, fixedvertices)
+    Matching(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), g, weights, Dict{Tuple{Int,Int},Int}(fixedvertices))
 end
 
 flavors(::Type{<:Matching}) = [0, 1]
diff --git a/src/networks/MaxCut.jl b/src/networks/MaxCut.jl
index 8082d282..12be6e39 100644
--- a/src/networks/MaxCut.jl
+++ b/src/networks/MaxCut.jl
@@ -27,7 +27,7 @@ end
 function MaxCut(g::SimpleGraph; weights=NoWeight(), openvertices=(), fixedvertices=Dict{Int,Int}(), optimizer=GreedyMethod(), simplifier=nothing)
     @assert weights isa NoWeight || length(weights) == ne(g)
     rawcode = EinCode([[minmax(e.src,e.dst)...] for e in Graphs.edges(g)], collect(Int, openvertices))  # labels for edge tensors
-    MaxCut(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), g, weights, fixedvertices)
+    MaxCut(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), g, weights, Dict{Int,Int}(fixedvertices))
 end
 
 flavors(::Type{<:MaxCut}) = [0, 1]
diff --git a/src/networks/MaximalIS.jl b/src/networks/MaximalIS.jl
index 135532f8..773c7273 100644
--- a/src/networks/MaximalIS.jl
+++ b/src/networks/MaximalIS.jl
@@ -28,7 +28,7 @@ end
 function MaximalIS(g::SimpleGraph; weights=NoWeight(), openvertices=(), optimizer=GreedyMethod(), simplifier=nothing, fixedvertices=Dict{Int,Int}())
     @assert weights isa NoWeight || length(weights) == nv(g)
     rawcode = EinCode(([[Graphs.neighbors(g, v)..., v] for v in Graphs.vertices(g)]...,), collect(Int, openvertices))
-    MaximalIS(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), g, weights, fixedvertices)
+    MaximalIS(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), g, weights, Dict{Int,Int}(fixedvertices))
 end
 
 flavors(::Type{<:MaximalIS}) = [0, 1]
diff --git a/src/networks/PaintShop.jl b/src/networks/PaintShop.jl
index f4d58cc5..588176c7 100644
--- a/src/networks/PaintShop.jl
+++ b/src/networks/PaintShop.jl
@@ -44,7 +44,7 @@ struct PaintShop{CT<:AbstractEinsum,LT} <: GraphProblem
     fixedvertices::Dict{LT,Int}
 end
 
-function paintshop_from_pairs(pairs::AbstractVector{Tuple{Int,Int}}; openvertices=(), optimizer=GreedyMethod(), simplifier=nothing, fixedvertices=Dict{LT,Int}())
+function paintshop_from_pairs(pairs::AbstractVector{Tuple{Int,Int}}; openvertices=(), optimizer=GreedyMethod(), simplifier=nothing, fixedvertices=Dict())
     n = length(pairs)
     @assert sort!(vcat(collect.(pairs)...)) == collect(1:2n)
     sequence = zeros(Int, 2*n)
@@ -61,7 +61,7 @@ function PaintShop(sequence::AbstractVector{T}; openvertices=(), fixedvertices=D
                 [[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, fixedvertices)
+    PaintShop(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), sequence, isfirst, Dict{T,Int}(fixedvertices))
 end
 
 flavors(::Type{<:PaintShop}) = [0, 1]
@@ -106,4 +106,4 @@ function paint_shop_coloring_from_config(p::PaintShop{CT,LT}, config) where {CT,
     return map(1:length(p.sequence)) do i
         p.isfirst[i] ? d[p.sequence[i]] : ~d[p.sequence[i]]
     end
-end
\ No newline at end of file
+end
diff --git a/src/networks/Satisfiability.jl b/src/networks/Satisfiability.jl
index 2da7c914..8f93200f 100644
--- a/src/networks/Satisfiability.jl
+++ b/src/networks/Satisfiability.jl
@@ -161,7 +161,7 @@ end
 
 function Satisfiability(cnf::CNF{T}; weights=NoWeight(), openvertices=(), optimizer=GreedyMethod(), simplifier=nothing, fixedvertices=Dict{T,Int}()) where T
     rawcode = EinCode([[getfield.(c.vars, :name)...] for c in cnf.clauses], collect(T, openvertices))
-    Satisfiability(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), cnf, weights, fixedvertices)
+    Satisfiability(_optimize_code(rawcode, uniformsize_fix(rawcode, 2, fixedvertices), optimizer, simplifier), cnf, weights, Dict{T,Int}(fixedvertices))
 end
 
 flavors(::Type{<:Satisfiability}) = [0, 1]  # false, true
diff --git a/src/networks/SetCovering.jl b/src/networks/SetCovering.jl
index 620456a0..4214edf4 100644
--- a/src/networks/SetCovering.jl
+++ b/src/networks/SetCovering.jl
@@ -44,7 +44,7 @@ function SetCovering(sets::AbstractVector{Vector{ET}}; weights=NoWeight(), openv
 
     code = EinCode([[[i] for i=1:nsets]...,
         [count[e] for e in elements]...], collect(Int,openvertices))
-    SetCovering(_optimize_code(code, uniformsize_fix(code, 2, fixedvertices), optimizer, simplifier), sets, weights, fixedvertices)
+    SetCovering(_optimize_code(code, uniformsize_fix(code, 2, fixedvertices), optimizer, simplifier), sets, weights, Dict{ET,Int}(fixedvertices))
 end
 
 function cover_count(sets)
diff --git a/src/networks/SetPacking.jl b/src/networks/SetPacking.jl
index aff3fa4f..bf484cf8 100644
--- a/src/networks/SetPacking.jl
+++ b/src/networks/SetPacking.jl
@@ -40,7 +40,7 @@ function SetPacking(sets::AbstractVector{Vector{ET}}; weights=NoWeight(), openve
     nsets = length(sets)
     @assert weights isa NoWeight || length(weights) == nsets
     code = EinCode(vcat([[i] for i=1:nsets], [[i,j] for i=1:nsets,j=1:nsets if j>i && !isempty(sets[i] ∩ sets[j])]), collect(Int,openvertices))
-    SetPacking(_optimize_code(code, uniformsize_fix(code, 2, openvertices), optimizer, simplifier), sets, weights, fixedvertices)
+    SetPacking(_optimize_code(code, uniformsize_fix(code, 2, openvertices), optimizer, simplifier), sets, weights, Dict{ET,Int}(fixedvertices))
 end
 
 flavors(::Type{<:SetPacking}) = [0, 1]
diff --git a/test/networks/Coloring.jl b/test/networks/Coloring.jl
index 4f066fc1..87ab2497 100644
--- a/test/networks/Coloring.jl
+++ b/test/networks/Coloring.jl
@@ -6,11 +6,11 @@ using Test, GenericTensorNetworks, Graphs
         add_edge!(g, i, j)
     end
     code = Coloring{3}(g; optimizer=GreedyMethod())
-    res = best_solutions(code; all=true)[]
+    res = GenericTensorNetworks.best_solutions(code; all=true)[]
     @test length(res.c.data) == 12
     g = smallgraph(:petersen)
     code = Coloring{3}(g; optimizer=GreedyMethod())
-    res = best_solutions(code; all=true)[]
+    res = GenericTensorNetworks.best_solutions(code; all=true)[]
     @test length(res.c.data) == 120
 
     c = solve(code, SingleConfigMax())[]
diff --git a/test/networks/Matching.jl b/test/networks/Matching.jl
index 48148960..a7bfc937 100644
--- a/test/networks/Matching.jl
+++ b/test/networks/Matching.jl
@@ -1,11 +1,17 @@
 using Test, GenericTensorNetworks, Graphs
+using GenericTensorNetworks: solutions
 
 @testset "enumerating - matching" begin
     g = smallgraph(:petersen)
-    code = Matching(g; optimizer=GreedyMethod())
+    code = Matching(g; optimizer=GreedyMethod(), fixedvertices=Dict())
     res = solutions(code, CountingTropicalF64; all=true)[]
     @test res.n == 5
     @test length(res.c.data) == 6
+    code = Matching(g; optimizer=GreedyMethod(), fixedvertices=Dict((1,2)=>1))
+    res = solutions(code, CountingTropicalF64; all=true)[]
+    @test res.n == 5
+    k = findfirst(x->x==(1,2), labels(code))
+    @test length(res.c.data) == 2 && res.c.data[1][k] == 1 && res.c.data[2][k] == 1
 end
 
 @testset "match polynomial" begin
diff --git a/test/networks/MaxCut.jl b/test/networks/MaxCut.jl
index 7c8c2a36..52d1be25 100644
--- a/test/networks/MaxCut.jl
+++ b/test/networks/MaxCut.jl
@@ -35,7 +35,7 @@ end
         add_edge!(g, i, j)
     end
     code = MaxCut(g; optimizer=GreedyMethod())
-    res = best_solutions(code; all=true)[]
+    res = GenericTensorNetworks.best_solutions(code; all=true)[]
     @test length(res.c.data) == 2
     @test cut_size(g, res.c.data[1]) == 5
 end
diff --git a/test/networks/MaximalIS.jl b/test/networks/MaximalIS.jl
index fdd908cc..8b9d8387 100644
--- a/test/networks/MaximalIS.jl
+++ b/test/networks/MaximalIS.jl
@@ -1,4 +1,5 @@
 using GenericTensorNetworks, Test, Graphs
+using GenericTensorNetworks: graph_polynomial
 
 @testset "counting maximal IS" begin
     g = random_regular_graph(20, 3)
diff --git a/test/networks/Satisfiability.jl b/test/networks/Satisfiability.jl
index ee32d4be..d3135cbd 100644
--- a/test/networks/Satisfiability.jl
+++ b/test/networks/Satisfiability.jl
@@ -33,7 +33,7 @@ end
     gp = Satisfiability(cnf)
 
     @test solve(gp, SizeMax())[].n == 4.0
-    res = best_solutions(gp; all=true)[].c.data
+    res = GenericTensorNetworks.best_solutions(gp; all=true)[].c.data
     for i=0:1<<6-1
         v = StaticBitVector(Bool[i>>(k-1) & 1 for k=1:6])
         if v ∈ res
@@ -54,7 +54,7 @@ end
     gp = Satisfiability(cnf; weights=fill(2, length(cnf)))
 
     @test solve(gp, SizeMax())[].n == 8.0
-    res = best_solutions(gp; all=true)[].c.data
+    res = GenericTensorNetworks.best_solutions(gp; all=true)[].c.data
     for i=0:1<<6-1
         v = StaticBitVector(Bool[i>>(k-1) & 1 for k=1:6])
         if v ∈ res
diff --git a/test/networks/SetPacking.jl b/test/networks/SetPacking.jl
index 65ed2e1b..c0573145 100644
--- a/test/networks/SetPacking.jl
+++ b/test/networks/SetPacking.jl
@@ -3,7 +3,7 @@ using GenericTensorNetworks, Test, Graphs
 @testset "set packing" begin
     sets = [[1, 2, 5], [1, 3], [2, 4], [3, 6], [2, 3, 6]]  # each set is a vertex
     gp = SetPacking(sets; optimizer=GreedyMethod())
-    res = best_solutions(gp; all=true)[]
+    res = GenericTensorNetworks.best_solutions(gp; all=true)[]
     @test res.n == 2
     @test BitVector(Bool[0,0,1,1,0]) ∈ res.c.data
     @test BitVector(Bool[1,0,0,1,0]) ∈ res.c.data