function [D2,e_l,e_r,d1_l,d1_r] = assemble_D2(stencil,h,m)
  stencil_variables = read_stencil(stencil);  
  D2 = assemble_op(stencil_variables.inner_stencil,stencil_variables.boundary_stencils,m,1)/h^2;
  [e_l, e_r] = assemble_boundary_op(stencil_variables.e,m);
  [d1_l, d1_r] = assemble_boundary_op(stencil_variables.d1,m);
  d1_l = d1_l/h;
  d1_r = -d1_r/h;
  end