anchor.diff:         rewind(udata)
   
          ! allocate memory for data
  -       allocate(seqs(nvars,nseqs),stat=err)
  +       allocate(seqs(nvars, nseqs), stat=err)
   
          ! read data
  -       do i = 1,nseqs
  -          read(udata,*,iostat=err) seqs(:,i)
  +       do i = 1, nseqs
  +          read(udata, *, iostat=err) seqs(:, i)
             if(err > 0) then 
                error_code = 20
                return
  
positive.code:     case('bio', 'protein', 'nuc_acid')
  
         ! read sequences from MSA
         call fasta_read(udata,seqs,data_type,error_code,error_string)
         if (error_code /= 0) return
         nseqs = size(seqs,2)
         if (nvars == 0) nvars = size(seqs,1)
  
      end select
  
      allocate(ws(nseqs),stat=err)
      ! initialize weigths to one
      ws = 1.0_kflt
  
      if ( uwgt > 0 ) then 
         ! count lines
         nn = 0
         do
            read(uwgt,'(a)',iostat=err) line
            ! exit at end of file or empty line
            if( err < 0 .or. len_trim(line) == 0) exit
            nn = nn + 1
         end do
  
         rewind(uwgt)
         if ( nn /= nseqs ) then
            error_code = 23
            return
         end if
  
         do i = 1,nseqs
            read(uwgt,*,iostat=err) ws(i)
            if(err > 0) then 
               error_code = 21
               return
  
negative.code:        ! count data lines
         nseqs = 0
         do
            read(udata, '(a)', iostat=err) line
            ! exit at end of file or empty line
            if( err < 0 .or. len_trim(line) == 0) exit
            nseqs = nseqs + 1
  