anchor.diff:  
     !  Column formats
     ! ================
  -  integer, parameter :: dist_fmtNONE        = 0
  -  integer, parameter :: dist_fmtPartID      = 1
  -  integer, parameter :: dist_fmtParentID    = 2
  +  integer, parameter :: dist_fmtNONE        = 0  ! Column ignored
  +  integer, parameter :: dist_fmtPartID      = 1  ! Paricle ID
  +  integer, parameter :: dist_fmtParentID    = 2  ! Particle parent ID (for secondary particles, otherwise equal particle ID)
   
     ! Physical Coordinates
     integer, parameter :: dist_fmtX           = 11 ! Horizontal position
  
positive.code:   case("CHARGE","Q")
      call dist_appendFormat(dist_fmtCHARGE, one)      ! Particle charge
    case("ION_A")
      call dist_appendFormat(dist_fmtIonA, one)        ! Ion atomic number
    case("ION_Z")
      call dist_appendFormat(dist_fmtIonZ, one)        ! Ion atomic charge
    case("PDGID")
      call dist_appendFormat(dist_fmtPDGID, one)       ! Particle PDG ID
  
  
negative.code:   cErr = .false.
  
    if(dist_hasFormat .eqv. .false.) then
      call dist_setColumnFormat("OLD_DIST",cErr)
    end if
  
    call f_open(unit=dist_readUnit,file=dist_readFile,mode='r',err=cErr,formatted=.true.,status="old")
  