anchor.diff:         end if
          rewind(fn_in)
          allocate(c(3,n))
  -       allocate(gr(nb))
  -       allocate(gr0(nb))
          allocate(atag(n))
          allocate(oc1(n))
          allocate(oc2(n))
  
positive.code:            call xyz_read(n,c,atag,fn_in)
             ok=n.ne.0
           end if
  C         do i=1,n
  C           write(88,*) i,atag(i),(c(k,i),k=1,3)
  C         end do
  C         stop
           if(.not.ok) exit
           write(*,*) "number of atoms", n
           oc1=.false.
  
negative.code:           end if
            go to 16
         else 
                 write(*,*) "file buffer", buffer
            nfil = nfil+1
            infile(nfil) = buffer
            go to 16
         end if 
         
  c      ---------------------------      
  c      end of command line parsing
  c      ---------------------------      
  