Python Configuration Classes

DisortFlags

flags = disortpp.DisortFlags()

All members are read/write attributes:

Attribute	Type	Description
use_user_tau	bool	Return output at user-specified optical depths.
use_user_mu	bool	Return intensities at user-specified polar angles.
ibcnd	BoundaryConditionType	Boundary condition type (General or Special).
use_lambertian_surface	bool	Use Lambertian surface reflection.
use_thermal_emission	bool	Include thermal emission.
use_spherical_beam	bool	Pseudo-spherical beam geometry.
comp_only_fluxes	bool	Compute only fluxes (skip angular intensities).
brdf_type	BrdfType	BRDF model for the surface.
intensity_corr_buras	bool	Buras & Emde intensity correction.
intensity_corr_nakajima	bool	Nakajima & Tanaka intensity correction.
use_delta_m_plus	bool	Use Delta-M+ scaling.
use_diffusion_lower_bc	bool	Use the diffusion approximation as the lower boundary condition (for stellar atmospheres). Sets \(I(\mu) = B(T_\mathrm{bottom}) + \mu\,\mathrm{d}B/\mathrm{d}\tau\). Requires use_thermal_emission = True.
output_fourier_expansion	bool	Return Fourier expansion of intensity.

BoundaryConditions

bc = disortpp.BoundaryConditions()

Attribute	Type	Description
direct_beam_flux	float	Incident parallel beam intensity.
direct_beam_mu	float	Cosine of beam polar angle.
direct_beam_phi	float	Azimuth angle of beam [deg].
isotropic_flux_top	float	Isotropic illumination at top.
isotropic_flux_bottom	float	Isotropic illumination at bottom.
temperature_top	float	Top boundary temperature [K].
temperature_bottom	float	Bottom boundary temperature [K].
emissivity_top	float	Top boundary emissivity.
surface_albedo	float	Lambertian surface albedo.

BRDF specifications

rpv = disortpp.RpvBrdfSpec()           # rho0, k, theta, sigma, t1, t2, scale
ambrals = disortpp.AmbralsBrdfSpec()   # iso, vol, geo
cox_munk = disortpp.CoxMunkBrdfSpec()  # u10, pcl, xsal, refractive_index, do_shadow
hapke = disortpp.HapkeBrdfSpec()       # b0, hh, w

brdf = disortpp.BrdfSpecification()
brdf.set_rpv(rpv)
brdf.set_ambrals(ambrals)
brdf.set_cox_munk(cox_munk)
brdf.set_hapke(hapke)

All BRDF struct members are accessible as read/write attributes. See the C++ BRDF documentation for details on each parameter.

DisortConfig

Main configuration class for the general solver.

# Construct with dimensions
cfg = disortpp.DisortConfig(num_layers, num_streams)
cfg = disortpp.DisortConfig(num_layers, num_streams, num_phase_func_moments)

# Or default-construct and set dimensions manually
cfg = disortpp.DisortConfig()
cfg.num_layers = 4
cfg.num_streams = 16

Nested structs (read/write):

• cfg.flags – DisortFlags

• cfg.bc – BoundaryConditions

• cfg.brdf – BrdfSpecification

Dimension attributes:

• num_layers, num_streams, num_phase_func_moments

• num_user_tau, num_user_mu, num_phi

• num_phase_func_angles

Physical parameters:

• wavenumber_low, wavenumber_high (float)

• accuracy_fourier_series (float)

• bottom_radius (float)

Array attributes (set as Python lists after calling allocate()):

• delta_tau – Layer optical depths.

• single_scat_albedo – Layer single-scattering albedos.

• phase_function_moments – Nested list of Legendre moments.

• temperature – Level temperatures.

• level_altitudes – Level altitudes.

• tau_user – User optical depths.

• mu_user – User polar angle cosines.

• phi_user – User azimuthal angles [deg].

• mu_phase_function – Scattering angle grid.

• phase_function – Tabulated phase function values.

Methods:

cfg.nmom_nstr()

Returns max(num_phase_func_moments, num_streams).

cfg.allocate()

Allocate internal arrays. Call after setting all dimensions and flags.

cfg.validate()

Validate the configuration. Raises ValueError on invalid input.

cfg.set_henyey_greenstein(g, lc=-1)

Fill Henyey-Greenstein phase function moments (\(\chi_k = g^k\)). Set lc to fill only a specific layer (0-based), or -1 for all layers.

cfg.set_isotropic(lc=-1)

Set isotropic scattering.

cfg.set_rayleigh(lc=-1)

Set Rayleigh scattering.

cfg.set_haze_garcia_siewert(lc=-1)

Set Haze-L phase function.

cfg.set_cloud_garcia_siewert(lc=-1)

Set Cloud C.1 phase function.

cfg.set_phase_function(type, g=0.0, lc=-1)

Set phase function by enum type.

DisortFluxConfig

Lightweight configuration for the flux-only solver.

cfg = disortpp.DisortFluxConfig(num_layers, num_streams)

All fields are flat attributes (no nested structs):

Dimensions: num_layers, num_streams, num_phase_func_moments

Flags: use_thermal_emission, use_spherical_beam, use_delta_m_plus, use_diffusion_lower_bc

Boundary conditions: direct_beam_flux, direct_beam_mu, isotropic_flux_top, isotropic_flux_bottom, temperature_top, temperature_bottom, emissivity_top, surface_albedo

Physical parameters: wavenumber_low, wavenumber_high, bottom_radius

Arrays: delta_tau, single_scat_albedo, phase_function_moments, temperature, level_altitudes

Methods: Same as DisortConfig: nmom_nstr(), allocate(), validate(), set_henyey_greenstein(), set_isotropic(), set_rayleigh(), set_haze_garcia_siewert(), set_cloud_garcia_siewert(), set_phase_function().