updateSpectral Subroutine

    subroutine updateSpectral(this, wavelength)

        implicit none

        class(spectral), intent(inout) :: this
        real(kind=wp),   intent(out)   :: wavelength

        real(kind=wp) :: tmp

        !get wavelength
        call this%flux%sample(wavelength, tmp)

        !update mus
        call this%mus_a%sample(this%mus, tmp, wavelength)

        !update mua
        call this%mua_a%sample(this%mua, tmp, wavelength)

        !update hgg
        call this%hgg_a%sample(this%hgg, tmp, wavelength)

        this%g2 = this%hgg**2

        !update n
        call this%n_a%sample(this%n, tmp, wavelength)

        !update kappa and albedo
        this%kappa =  this%mus + this%mua
        this%albedo = this%mus / this%kappa

    end subroutine updateSpectral