Runtime Parameters Documentation for FLASH Release 3.2

        flags whether the Diffuse unit is being used

    diffusion_cutoff_density [REAL] [1.e-30]
        Valid Values: Unconstrained
        density below which we no longer diffuse
    dt_diff_factor [REAL] [0.8]
        Valid Values: Unconstrained
        factor that scales the timestep returned by Diffuse_computeDt
    geometric_mean_diff [BOOLEAN] [FALSE]

    thermal_diff_method [INTEGER] [1]
        Valid Values: Unconstrained

    useDiffuse [BOOLEAN] [TRUE]
        whether any method of the Diffuse unit should contribute to fluxes
    useDiffuseSpecies [BOOLEAN] [TRUE]
        whether Diffuse_species [TO BE IMPLEMENTED] should contribute to fluxes
    useDiffuseTherm [BOOLEAN] [TRUE]
        whether Diffuse_therm should contribute to fluxes
    useDiffuseVisc [BOOLEAN] [TRUE]
        whether Diffuse_visc should contribute to fluxes