function [D1,e_l,e_r] = assemble_D1(stencil,h,m)
  stencil_variables = read_stencil(stencil);
  
  D1 = assemble_op(stencil_variables.inner_stencil,stencil_variables.boundary_block,m)/h;
  [e_l, e_r] = assemble_boundary_op(stencil_variables);
  end