subroutine ewset (n, itol, rtol, atol, ycur, ewt)
clll. optimize
c-----------------------------------------------------------------------
c this subroutine sets the error weight vector ewt according to
c     ewt(i) = rtol(i)*abs(ycur(i)) + atol(i),  i = 1,...,n,
c with the subscript on rtol and/or atol possibly replaced by 1 above,
c depending on the value of itol.
c-----------------------------------------------------------------------
      integer n, itol
      integer i
      double precision rtol, atol, ycur, ewt
      dimension rtol(1), atol(1), ycur(n), ewt(n)
c
      go to (10, 20, 30, 40), itol
 10   continue
      do 15 i = 1,n
 15     ewt(i) = rtol(1)*dabs(ycur(i)) + atol(1)
      return
 20   continue
      do 25 i = 1,n
 25     ewt(i) = rtol(1)*dabs(ycur(i)) + atol(i)
      return
 30   continue
      do 35 i = 1,n
 35     ewt(i) = rtol(i)*dabs(ycur(i)) + atol(1)
      return
 40   continue
      do 45 i = 1,n
 45     ewt(i) = rtol(i)*dabs(ycur(i)) + atol(i)
      return
c----------------------- end of subroutine ewset -----------------------
      end