anchor.diff:         Q_l%data(i+1,iqxvel) = 0.0_dp_t
          Q_r%data(i,iqxvel) = 0.0_dp_t
   
  -       do n = 1, nprim
  +       do n = 1, nwaves
             if (eval(n) >= 0.0_dp_t) then
                Q_l%data(i+1,iqxvel) = Q_l%data(i+1,iqxvel) + &
  -                  beta_xp(n)*rvec(n,2)
  +                  beta_xp(n)*rvec(n,iqxvel)
             endif
   
             if (eval(n) <= 0.0_dp_t) then
                Q_r%data(i,iqxvel) = Q_r%data(i,iqxvel) + &
  -                  beta_xm(n)*rvec(n,2)
  +                  beta_xm(n)*rvec(n,iqxvel)
             endif
          enddo
   
  
positive.code:        Q_l%data(i+1,iqpres) = 0.0_dp_t
         Q_r%data(i,iqpres) = 0.0_dp_t
  
         do n = 1, nprim
            if (eval(n) >= 0.0_dp_t) then
               Q_l%data(i+1,iqpres) = Q_l%data(i+1,iqpres) + &
                    beta_xp(n)*rvec(n,3)
            endif
  
            if (eval(n) <= 0.0_dp_t) then
               Q_r%data(i,iqpres) = Q_r%data(i,iqpres) + &
                    beta_xm(n)*rvec(n,3)
            endif
         enddo
  
  
negative.code: 
  
         ! compute the dot product of each left eigenvector with (qref - I)
         do m = 1, nwaves    ! loop over waves
            beta_xm(m) = 0.0_dp_t
            beta_xp(m) = 0.0_dp_t
  
  