anchor.diff:      implicit none
   
       character(len=MAX_FILENAME_LEN), intent(in) :: FIELDFILE
  -    character(len=MAX_STRING_LEN), optional ::  radius_type
  +    character(len=MAX_STRING_LEN), optional ::  radius_type_in
       !     Local Variables
       integer :: ierror,ne,np,np1,np2,np_global,surround
  +    character(len=MAX_STRING_LEN) ::  radius_type
       character(LEN=132) :: ctemp1
       LOGICAL :: versions=.TRUE.
       real(dp) :: constrict,radius
  
positive.code: !##################################################################################
  !
  !*define_rad_from_geom:* Defines vessel or airway radius based on their geometric structure
    subroutine define_rad_from_geom(ORDER_SYSTEM,CONTROL_PARAM,START_FROM,START_RAD,GROUP_TYPE,GROUP_OPTIONS)
    !DEC$ ATTRIBUTES DLLEXPORT,ALIAS:"DLL_DEFINE_RAD_FROM_GEOM" :: DEFINE_RAD_FROM_GEOM
      use arrays,only: dp,num_elems,elem_field,elem_ordrs,maxgen,elem_cnct
      use indices
      use diagnostics, only: enter_exit
      implicit none
     character(LEN=100), intent(in) :: ORDER_SYSTEM,START_FROM
     character(LEN=100), optional :: GROUP_TYPE,GROUP_OPTIONS
     real(dp), intent(in) :: CONTROL_PARAM,START_RAD
     !Input options ORDER_SYSTEM=STRAHLER (CONTROL_PARAM=RDS), HORSFIELD (CONTROL_PARAM=RDH)
  
     !Local variables
     integer :: ne_min,ne_max,nindex,ne,n_max_ord,n,ne_start,&
        inlet_count
     real(dp) :: radius
  
negative.code: 
      sub_name = 'define_rad_from_file'
      call enter_exit(sub_name,1)
      if(present(radius_type_in))then
        radius_type = radius_type_in
      else
        radius_type = 'no_taper'
      endif
  
  !!! note that 'constrict' should not be used here (so is set to 1.0).
  