interpolation.H

		surfaceScalarField rho_pos(interpolate(rho, pos));
        surfaceScalarField rho_neg(interpolate(rho, neg));

        surfaceVectorField rhoU_pos(interpolate(rhoU, pos, U.name()));
        surfaceVectorField rhoU_neg(interpolate(rhoU, neg, U.name()));

        volScalarField rPsi("rPsi", 1.0/psi);
        surfaceScalarField rPsi_pos(interpolate(rPsi, pos, T.name()));
        surfaceScalarField rPsi_neg(interpolate(rPsi, neg, T.name()));

        surfaceScalarField e_pos(interpolate(e, pos, T.name()));
        surfaceScalarField e_neg(interpolate(e, neg, T.name()));

        surfaceVectorField U_pos("U_pos", rhoU_pos/rho_pos);
        surfaceVectorField U_neg("U_neg", rhoU_neg/rho_neg);

        surfaceScalarField p_pos("p_pos", rho_pos*rPsi_pos);
        surfaceScalarField p_neg("p_neg", rho_neg*rPsi_neg);

        surfaceScalarField phiv_pos("phiv_pos", U_pos & mesh.Sf());
        surfaceScalarField phiv_neg("phiv_neg", U_neg & mesh.Sf());

        volScalarField c("c", sqrt(thermo.Cp()/thermo.Cv()*rPsi));
        surfaceScalarField cSf_pos
        (
            "cSf_pos",
            interpolate(c, pos, T.name())*mesh.magSf()
        );
        surfaceScalarField cSf_neg
        (
            "cSf_neg",
            interpolate(c, neg, T.name())*mesh.magSf()
        );

        surfaceScalarField ap
        (
            "ap",
            max(max(phiv_pos + cSf_pos, phiv_neg + cSf_neg), v_zero)
        );
        surfaceScalarField am
        (
            "am",
            min(min(phiv_pos - cSf_pos, phiv_neg - cSf_neg), v_zero)
        );

        surfaceScalarField a_pos("a_pos", ap/(ap - am));

        surfaceScalarField amaxSf("amaxSf", max(mag(am), mag(ap)));

        surfaceScalarField aSf("aSf", am*a_pos);

        if (fluxScheme == "Tadmor")
        {
            aSf = -0.5*amaxSf;
            a_pos = 0.5;
        }

        surfaceScalarField a_neg("a_neg", 1.0 - a_pos);

        phiv_pos *= a_pos;
        phiv_neg *= a_neg;

        surfaceScalarField aphiv_pos("aphiv_pos", phiv_pos - aSf);
        surfaceScalarField aphiv_neg("aphiv_neg", phiv_neg + aSf);

        // Reuse amaxSf for the maximum positive and negative fluxes
        // estimated by the central scheme
        amaxSf = max(mag(aphiv_pos), mag(aphiv_neg));