  a(1) = 2.0/3.0
  a(2) = -1.0/12.0

  q(1,1) = -24.0/17.0
  q(2,1) = 59.0/34.0
  q(3,1) = -4.0/17.0
  q(4,1) = -3.0/34.0
  q(5,1) = 0
  q(6,1) = 0

  q(1,2) = -1.0/2.0
  q(2,2) = 0
  q(3,2) = 1.0/2.0
  q(4,2) = 0
  q(5,2) = 0
  q(6,2) = 0

  q(1,3) = 4.0/43.0
  q(2,3) = -59.0/86.0
  q(3,3) = 0
  q(4,3) = 59.0/86.0
  q(5,3) = -4.0/43.0
  q(6,3) = 0

  q(1,4) = 3.0/98.0
  q(2,4) = 0
  q(3,4) = -59.0/98.0
  q(4,4) = 0
  q(5,4) = 32.0/49.0
  q(6,4) = -4.0/49.0

  # from https://bitbucket.org/cactuscode/cactusnumerical/src/master/SummationByParts/src/GetScalProdDiag.F90
  CCTK_REAL, dimension(4), parameter :: bmask_4 = (/ 17.0_wp/48.0_wp, &
                                                     59.0_wp/48.0_wp, &
                                                     43.0_wp/48.0_wp, &
                                                     49.0_wp/48.0_wp /)
