How to use the libceed.VECTOR_NONE function in libceed

b = ceed.BasisH1(libceed.TRIANGLE, 1, P, Q, interp, grad, qref, qweight)

  # Interpolate function to quadrature points
  for i in range(P):
    in_array[i] = feval(xr[0*P+i], xr[1*P+i])

  in_vec = ceed.Vector(P)
  in_vec.set_array(in_array, cmode=libceed.USE_POINTER)
  out_vec = ceed.Vector(Q)
  out_vec.set_value(0)
  weights_vec = ceed.Vector(Q)
  weights_vec.set_value(0)

  b.apply(1, libceed.EVAL_INTERP, in_vec, out_vec)
  b.apply(1, libceed.EVAL_WEIGHT, libceed.VECTOR_NONE, weights_vec)

  # Check values at quadrature points
  out_array = out_vec.get_array_read()
  weights_array = weights_vec.get_array_read()
  sum = 0
  for i in range(Q):
    sum += out_array[i]*weights_array[i]
  assert math.fabs(sum - 17./24.) < 1E-10

  out_vec.restore_array_read()
  weights_vec.restore_array_read()

b = ceed.BasisH1(libceed.TRIANGLE, 1, P, Q, interp, grad, qref, qweight)

  # Interpolate function to quadrature points
  for i in range(P):
    in_array[i] = feval(xr[0*P+i], xr[1*P+i])

  in_vec = ceed.Vector(P)
  in_vec.set_array(in_array, cmode=libceed.USE_POINTER)
  out_vec = ceed.Vector(Q)
  out_vec.set_value(0)
  weights_vec = ceed.Vector(Q)
  weights_vec.set_value(0)

  b.apply(1, libceed.EVAL_INTERP, in_vec, out_vec)
  b.apply(1, libceed.EVAL_WEIGHT, libceed.VECTOR_NONE, weights_vec)

  # Check values at quadrature points
  out_array = out_vec.get_array_read()
  weights_array = weights_vec.get_array_read()
  sum = 0
  for i in range(Q):
    sum += out_array[i]*weights_array[i]
  if math.fabs(sum - 17./24.) > 1E-10:
    print("%f != %f"%(sum, 17./24.))

  out_vec.restore_array_read()
  weights_vec.restore_array_read()

qf_setup = ceed.QFunction(1, qfs.setup_mass,
                            os.path.join(file_dir, "test-qfunctions.h:setup_mass"))
  qf_setup.add_input("weights", 1, libceed.EVAL_WEIGHT)
  qf_setup.add_input("dx", 1, libceed.EVAL_GRAD)
  qf_setup.add_output("rho", 1, libceed.EVAL_NONE)

  qf_mass = ceed.QFunction(1, qfs.apply_mass,
                           os.path.join(file_dir, "test-qfunctions.h:apply_mass"))
  qf_mass.add_input("rho", 1, libceed.EVAL_NONE)
  qf_mass.add_input("u", 1, libceed.EVAL_INTERP)
  qf_mass.add_output("v", 1, libceed.EVAL_INTERP)

  # Operators
  op_setup = ceed.Operator(qf_setup)
  op_setup.set_field("weights", rxi, bx, libceed.VECTOR_NONE)
  op_setup.set_field("dx", rx, bx, libceed.VECTOR_ACTIVE)
  op_setup.set_field("rho", rui, libceed.BASIS_COLLOCATED,
                     libceed.VECTOR_ACTIVE)

  op_mass = ceed.Operator(qf_mass)
  op_mass.set_field("rho", rui, libceed.BASIS_COLLOCATED, qdata)
  op_mass.set_field("u", ru, bu, libceed.VECTOR_ACTIVE)
  op_mass.set_field("v", ru, bu, libceed.VECTOR_ACTIVE)

  # Setup
  op_setup.apply(x, qdata)

  # Apply mass matrix
  u.set_value(0)
  op_mass.apply(u, v)

# QFunctions
  qf_setup_hex = ceed.QFunction(1, qfs.setup_mass_2d,
                                os.path.join(file_dir, "test-qfunctions.h:setup_mass_2d"))
  qf_setup_hex.add_input("weights", 1, libceed.EVAL_WEIGHT)
  qf_setup_hex.add_input("dx", dim*dim, libceed.EVAL_GRAD)
  qf_setup_hex.add_output("rho", 1, libceed.EVAL_NONE)

  qf_mass_hex = ceed.QFunction(1, qfs.apply_mass,
                               os.path.join(file_dir, "test-qfunctions.h:apply_mass"))
  qf_mass_hex.add_input("rho", 1, libceed.EVAL_NONE)
  qf_mass_hex.add_input("u", 1, libceed.EVAL_INTERP)
  qf_mass_hex.add_output("v", 1, libceed.EVAL_INTERP)

  # Operators
  op_setup_hex = ceed.Operator(qf_setup_tet)
  op_setup_hex.set_field("weights", rxi_hex, bx_hex, libceed.VECTOR_NONE)
  op_setup_hex.set_field("dx", rx_hex, bx_hex, libceed.VECTOR_ACTIVE)
  op_setup_hex.set_field("rho", rui_hex, libceed.BASIS_COLLOCATED,
                         qdata_hex)

  op_mass_hex = ceed.Operator(qf_mass_hex)
  op_mass_hex.set_field("rho", rui_hex, libceed.BASIS_COLLOCATED, qdata_hex)
  op_mass_hex.set_field("u", ru_hex, bu_hex, libceed.VECTOR_ACTIVE)
  op_mass_hex.set_field("v", ru_hex, bu_hex, libceed.VECTOR_ACTIVE)

  ## ------------------------- Composite Operators -------------------------

  # Setup
  op_setup = ceed.CompositeOperator()
  op_setup.add_sub(op_setup_tet)
  op_setup.add_sub(op_setup_hex)