anchor.diff:  
           parent_flag = 0_int_p
           do i = 1, size(parent_population), 2
  -            if (.not.((sqrt(parent_population(i) ** 2 + parent_population(i+1) ** 2) > initiator_pop) .or.&
  -                    (determ_flag == 0))) then
  +            if ((.not. ((parent_population(i) ** 2) + (parent_population(i+1) ** 2)) > &
  +                    initiator_pop ** 2) .or. (.not.(determ_flag == 0))) then
                   ! Isn't an initiator.
  +                parent_flag = ibset(parent_flag, i - 1)
                   parent_flag = ibset(parent_flag, i)
  -                parent_flag = ibset(parent_flag, i + 1)
               end if
               ! Otherwise has a high enough population to be an initiator in this space,
               ! or is a deterministic state (which must always be an initiator).
  
positive.code:         ! Out:
          !    parent_flag: set to 0 if the determinant is an initiator and 1 otherwise.
  
          real(p), intent(in) :: parent_population(:), initiator_pop
          integer, intent(in) :: determ_flag
          integer, intent(out) :: parent_flag
  
negative.code:         do i = 1, size(parent_population)
              if (.not.(abs(parent_population(i)) > initiator_pop .or. determ_flag == 0)) then
                  ! Isn't an initiator.
                  parent_flag = ibset(parent_flag, i - 1)
              ! Otherwise has a high enough population to be an initiator in this space,
              ! or is a deterministic state (which must always be an initiator).
              end if
  