Fix respectful_similar with SparsityPatternCSC

Author: blegat

src/matrices.jl

@@ -49,6 +49,17 @@ respectful_similar(A::AbstractMatrix) = respectful_similar(A, eltype(A))
 
 respectful_similar(A::AbstractMatrix, ::Type{T}) where {T} = similar(A, T)
 
+# Needed if using `coloring(::SparsityPatternCSC, ...)`
+function respectful_similar(A::SparsityPatternCSC, ::Type{T}) where {T}
+    return SparseArrays.SparseMatrixCSC(
+        A.m,
+        A.n,
+        A.colptr,
+        A.rowval,
+        similar(A.rowval, T),
+    )
+end
+
 function respectful_similar(A::Transpose, ::Type{T}) where {T}
     return transpose(respectful_similar(parent(A), T))
 end