Added integration test

Project.toml

@@ -13,6 +13,8 @@ julia = "1"
 
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+DiffEqDiffTools = "01453d9d-ee7c-5054-8395-0335cb756afa"
 
 [targets]
-test = ["Test"]
+test = ["Test", "LinearAlgebra", "DiffEqDiffTools"]

src/matrix2graph.jl

@@ -10,7 +10,7 @@ sparse matrix, columns are represented with vertices
 and 2 vertices are connected with an edge only if
 the two columns are mutually orthogonal.
 """
-function matrix2graph(SparseMatrix::SparseMatrixCSC{Int64,Int64})
+function matrix2graph(SparseMatrix::SparseMatrixCSC{T,Int}) where T<:Number
     dropzeros(SparseMatrix)
     (rows_index, cols_index, val) = findnz(SparseMatrix)
 

test/runtests.jl

@@ -5,3 +5,4 @@ using Test
 @testset "Exact coloring via contraction" begin include("test_contraction.jl") end
 @testset "Greedy distance-1 coloring" begin include("test_greedy_d1.jl") end
 @testset "Matrix to graph conversion" begin include("test_matrix2graph.jl") end
+@testset "Integration test" begin include("test_integration.jl") end

test/test_integration.jl

@@ -0,0 +1,49 @@
+using SparseDiffTools
+using LinearAlgebra
+using DiffEqDiffTools
+using Test
+
+fcalls = 0
+function f(dx,x)
+  global fcalls += 1
+  for i in 2:length(x)-1
+    dx[i] = x[i-1] - 2x[i] + x[i+1]
+  end
+  dx[1] = -2x[1] + x[2]
+  dx[end] = x[end-1] - 2x[end]
+  nothing
+end
+
+function second_derivative_stencil(N)
+  A = zeros(N,N)
+  for i in 1:N, j in 1:N
+      (j-i==-1 || j-i==1) && (A[i,j]=1)
+      j-i==0 && (A[i,j]=-2)
+  end
+  A
+end
+
+function generate_sparsity_pattern(N::Integer)
+    dl = repeat([1.0],N-1)
+    du = repeat([1.0],N-1)
+    d = repeat([-2.0],N)
+    return Tridiagonal(dl,d,du)
+end
+
+sparsity_pattern = sparse(generate_sparsity_pattern(30))
+
+_graph = matrix2graph(sparsity_pattern)
+coloring_vector = greedy_d1(_graph)
+@test coloring_vector == repeat(1:3,10)
+
+#Jacobian computed without coloring vector
+J = DiffEqDiffTools.finite_difference_jacobian(f, rand(30))
+@test J ≈ second_derivative_stencil(30)
+@test fcalls == 31
+
+#Jacobian computed with coloring vectors
+fcalls = 0
+_J = sparsity_pattern
+DiffEqDiffTools.finite_difference_jacobian!(_J, f, rand(30), color = coloring_vector)
+@test fcalls == 4
+@test _J ≈ J