anchor.diff:    character(len=long_string_size) :: frmt
     character(len=long_string_size) :: line, parsed_line
     integer :: flag=0 ! 1: u -> f; 2: f-> u
  +  integer :: nerrs=0
   
     call units_initialize()
  -  
  +
     ! read arguments
     call get_command(cmd)
     nargs = command_argument_count()
  -  
  +
     ! call with no args
     if (nargs == 0) then
  -     write(0,*) 'help'
  +     write(0,100)
        stop
     end if
   
  
positive.code:         if (flag == 0) then
             flag = 2
          else
             write(0,*) "either -u <unformatted_file > or -f <formatted_file> option"
             stop
          end if
          iarg = iarg + 1
          call read_opt_arg(iarg,nargs,source,err)
          if (err == 2) then
             write(0,*) 'ERROR ! missing argument: '//trim(arg)//' <filename>'
             stop
          end if
       case('-d', '--digits')
  
negative.code:      ! read nvars
       call parse_next_line(unt, line, parsed_line, nfields, err)
       if (err < 0) then
          write(0,*) "ERROR: invalid formatted input file"
          stop
       end if
       read(parsed_line, *, iostat=err) nvars
       if (err < 0) then
          write(0,*) "check n. of features"
          stop
       end if
  
       ! read nclasses
       call parse_next_line(unt, line, parsed_line, nfields, err)
       if (err < 0) then
          write(0,*) "input file can be converted to a valid checkpoint file"
          stop
       end if
       read(parsed_line, *, iostat=err) nclasses
       if (err < 0) then
          write(0,*) "check n. of classes"
          stop
       end if
  
       ! read data type
       call parse_next_line(unt, line, parsed_line, nfields, err)
       if (err < 0) then
          write(0,*) "input file can be converted to a valid checkpoint file"
          stop
       end if
       read(parsed_line, *, iostat=err) data_type
       if (err < 0) then
          write(0,*) "check output data type format"
          stop
       end if
  
       ! read ndata
       call parse_next_line(unt, line, parsed_line, nfields, err)
       if (err < 0) then
          write(0,*) "input file can be converted to a valid checkpoint file"
          stop
       end if
       read(parsed_line, *, iostat=err) ndata
       if (err < 0) then
          write(0,*) "check n. of samples in .chk file"
          stop
       end if
  
       ! if the first lines are ok, allocate
       allocate(prm(nvars*nclasses + nvars*(nvars - 1)*nclasses**2/2),stat=err)
       prm = 0.0_kflt
  