anchor.diff:  
   ! [review] - JSS: RDMs here are DMQMC-specific.  Should there be further dmqmc_data, fciqmc_data,
   ! [review] - JSS: ccmc_data, etc modules?
  +! [review] - NSB: Yes, I think that's sensible.
   
   ! Spawned lists for rdms.
   type rdm_spawn_t
  
positive.code: ! [review] - NSB: changed it to a parameter. This can probably be global data
  ! [review] - NSB: since it is constant.
  ! [review] - JSS: Applicable only to Heisenberg model?  If so, please can it have a more specific name?
  ! This will store the 4x4 flip spin matrix \sigma_y \otimes \sigma_y if
  ! concurrence is to be calculated.
  real(p), parameter :: flip_spin_matrix(4,4) = (\ 0.0_p,  0.0_p, 0.0_p, -1.0_p,  &
  
negative.code: end type folded_spect_t
  
  ! [review] - JSS: input options (also, should we remove initiator_cas?)
  ! [review] - NSB: Yes I think that initiator_cas should be removed.
  type initiator_t
      ! Complete active space within which a determinant is an initiator.
      ! (0,0) corresponds to the reference determinant only.
  