subroutine dystbl (store,ybar,sbar,n,j)
c----
c
c     This subroutine should store (if store = .true.) or restore
c     (if store = .false.) a pair (ybar,sbar) at or from position
c     j in memory. Be sure to have 1 <= j <= m, where m in the number
c     of updates specified by subroutine mupdts.
c
c     The subroutine is used only when the (y,s) pairs are not
c     stored in core memory in the arrays ybar(.,.) and sbar(.,.).
c     In this case, the subroutine has to be written by the user.
c
c----
c
c         arguments
c
      logical store
      integer n,j
      double precision ybar(n),sbar(n)
c
      return
      end