subroutine  calc_omega(omega, eta, qL, qR)

c------------------------------------------------------------
c  Calculates the characteristic jumps for Burger's equation.
c------------------------------------------------------------

         implicit      none

         character*10  cdnm
         parameter   ( cdnm = 'calc_omega' ) 

         logical       ltrace
         parameter   ( ltrace = .false. )

         real*8        omega
         real*8        eta

         real*8        qL,      qR

c============================================================
c============================================================
         if ( ltrace ) then
            write(0,*) cdnm,': qL=  ',qL
            write(0,*) cdnm,': qR=  ',qR
         endif
         omega = qR - qL
         if ( ltrace ) then
            write(0,*) cdnm,': omega=  ',omega
         endif
         return
         end