diff --git a/Solver_interface/doc/Solver_interface/Concepts/SparseLinearAlgebraTraits_d.h b/Solver_interface/doc/Solver_interface/Concepts/SparseLinearAlgebraTraits_d.h
index 5f54077d83c..1857644c9d2 100644
--- a/Solver_interface/doc/Solver_interface/Concepts/SparseLinearAlgebraTraits_d.h
+++ b/Solver_interface/doc/Solver_interface/Concepts/SparseLinearAlgebraTraits_d.h
@@ -127,6 +127,7 @@ NT& operator[](Index row);
 
 `SparseLinearAlgebraTraits_d::Matrix` is a concept of a sparse matrix class.
 
+\cgalRefines Assignable
 \cgalRefines DefaultConstructible
 
 \cgalHasModel `CGAL::Eigen_sparse_matrix<T>`
diff --git a/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/Iterative_authalic_parameterizer_3.h b/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/Iterative_authalic_parameterizer_3.h
index 2e475b11db8..938f1ec836f 100644
--- a/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/Iterative_authalic_parameterizer_3.h
+++ b/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/Iterative_authalic_parameterizer_3.h
@@ -50,7 +50,7 @@
 #include <iomanip>
 #include <unordered_set>
 
-#define DEBUG_L0 1 // @fixme
+#define DEBUG_L0 0 // @fixme
 
 /// \file Iterative_authalic_parameterizer_3.h
 
@@ -304,30 +304,6 @@ public:
   }
 
   // Computation helpers
-protected:
-  // `operator=(onst Matrix& other)` isn't part of the concept...
-  template <typename VertexIndexMap>
-  void copy_sparse_matrix(const Matrix& src,
-                          Matrix& dest,
-                          const Triangle_mesh& tmesh,
-                          const Vertex_set& vertices,
-                          const VertexIndexMap vimap)
-  {
-    CGAL_precondition(src.row_dimension() == dest.row_dimension());
-    CGAL_precondition(src.column_dimension() == dest.column_dimension());
-
-    for(vertex_descriptor vertex : vertices)
-    {
-      const int i = get(vimap, vertex);
-      vertex_around_target_circulator v_j(halfedge(vertex, tmesh), tmesh), end = v_j;
-      CGAL_For_all(v_j, end)
-      {
-        const int j = get(vimap, *v_j);
-        dest.set_coef(i, j, src.get_coef(i, j), false);
-      }
-    }
-  }
-
 private:
   double compute_vertex_L2(const Triangle_mesh& tmesh,
                            const vertex_descriptor v) const
@@ -997,8 +973,8 @@ public:
 //      for(std::size_t i=0; i<nv; ++i)
 //        std::cout << "Sol[" << i << "] = " << Xu[i] << " " << Xv[i] << std::endl;
 
-      // Copy A to A_prev, it is a computationally inefficient task but neccesary
-      copy_sparse_matrix(A, A_prev, tmesh, cc_vertices, vimap);
+      // Copy A to A_prev
+      A_prev = A;
 
       // Copy Xu and Xv coordinates into the (u,v) pair of each vertex
       for(vertex_descriptor v : cc_vertices)