rhosq2(iEdge) = one / (sqrtrho(iLft)+sqrtrho(iRgt))
uR(iEdge) = (q1D(iLft,mu)/sqrtrho(iLft) + q1D(iRgt,mu)/sqrtrho(iRgt)) * rhosq2(iEdge)
vR(iEdge) = (q1D(iLft,mv)/sqrtrho(iLft) + q1D(iRgt,mv)/sqrtrho(iRgt)) * rhosq2(iEdge)
hR(iEdge) = ((q1D(iLft,4)+pres(iLft))/sqrtrho(iLft) + &
(q1D(iRgt,4)+pres(iRgt))/sqrtrho(iRgt) ) * &
rhosq2(iEdge)
u2v2=uR**2+vR**2
cR = gamma1*(hR-half*u2v2)
IF (MINVAL(cR)<=zero) THEN
PRINT *,'Error: Negative or zero Roe average sound velocity in physflux.'
STOP
END IF
g1c2 = gamma1/cR
cR = SQRT(cR)
euv = hR - u2v2