Input Deck Reference

Auto-generated from schema.lua. Each table below documents one section of the config table.

config.basis

Key	Type	Default	Required	Description
nnodes	double	—	No	Number of DG nodes per cell.

config.bc

fluid

Key	Type	Default	Required	Description
bc_i	string	—	No	Inner fluid boundary condition. Options: ‘reflecting’, ‘outflow’, ‘dirichlet’, ‘periodic’.
dirichlet_values_o	array	—	No	Dirichlet state values at outer boundary.
dirichlet_values_i	array	—	No	Dirichlet state values at inner boundary.
bc_o	string	—	No	Outer fluid boundary condition. Options: ‘reflecting’, ‘outflow’, ‘dirichlet’, ‘periodic’.

radiation

Key	Type	Default	Required	Description
bc_i	string	—	No	Inner radiation boundary condition. Options: ‘reflecting’, ‘outflow’, ‘marshak’, ‘dirichlet’.
dirichlet_values_o	array	—	No	Dirichlet state values at outer boundary.
dirichlet_values_i	array	—	No	Dirichlet state values at inner boundary.
bc_o	string	—	No	Outer radiation boundary condition. Options: ‘reflecting’, ‘outflow’, ‘dirichlet’.

config.composition

Key	Type	Default	Required	Description
ncomps	int	—	No	Number of composition species.

config.engine

thermal

Key	Type	Default	Required	Description
mend	double	—	No	Mass coordinate of injection upper boundary in Msun. Must be > 0.
tend	double	—	No	End time for energy injection. Must be > 0.
energy	double	—	No	Total injected energy in erg.
operator_split	bool	false	No	Apply engine as operator-split source.
enabled	bool	—	No	Enable thermal energy injection engine.
mode	string	—	No	Injection mode. Options: ‘direct’, ‘asymptotic’.

config.eos

Key	Type	Default	Required	Description
n	double	—	No	Polytropic index n. Required for polytropic EOS.
k	double	—	No	Polytropic constant K. Required for polytropic EOS.
gamma	double	1.4	No	Adiabatic index. Default: 1.4.
type	string	—	No	Equation of state type. Options:. ‘ideal’, ‘paczynski’, ‘marshak’, ‘polytropic’.

config.fluid

limiter

Key	Type	Default	Required	Description
characteristic	bool	false	No	Enable characteristic limiting.
b_tvd	double	1.0	No	TVD parameter b. Used with minmod limiter.
tci_val	double	—	No	Troubled-cell indicator threshold.
m_tvb	double	0.0	No	TVB parameter M. Used with minmod limiter.
type	string	minmod	No	Limiter type. Options: ‘minmod’, ‘weno [experimental]’.
gamma_i	double	—	No	WENO central weight. Required for WENO limiter.
gamma_l	double	—	No	WENO left weight. Inferred from gamma_i if omitted.
gamma_r	double	—	No	WENO right weight. Inferred from gamma_i if omitted.
do_limiter	bool	true	No	Enable slope limiter for fluid.
weno_r	double	2.0	No	WENO smoothness exponent. Must be > 0.
tci_opt	bool	false	No	Enable troubled-cell indicator.

config.gravity

Key	Type	Default	Required	Description
model	string	—	No	Gravity model. Options: ‘constant’, ‘spherical’.
gval	double	—	No	Gravitational acceleration (constant model). Must be > 0.
operator_split	bool	false	No	Apply gravity as an operator-split source.

config.heating

nickel

Key	Type	Default	Required	Description
model	string	—	No	Nickel heating model. Options. ‘jeffery’ and ‘full_trapping’.
enabled	bool	—	No	Enable Ni56 decay heating.
operator_split	bool	false	No	Apply nickel heating as operator-split source.

config.ionization

Key	Type	Default	Required	Description
solver	string	linear	No	Saha solver mode. Options: ‘linear’, ‘log’.
ncomps	int	—	No	Number of species for Saha solver.
fn_ionization	string	—	No	Path to ionization atomic data file.
fn_degeneracy	string	—	No	Path to degeneracy factors atomic data file.

config.opacity

Key	Type	Default	Required	Description
kP	double	—	No	Planck mean opacity (cm^2/g). Required for constant and powerlaw.
filename	string	—	No	Path to tabular opacity HDF5 file.
t_exp	double	—	No	Temperature exponent for powerlaw opacity.
type	string	—	No	Opacity model. Options: ‘tabular’, ‘constant’, ‘powerlaw’.
kR_offset	double	0.0	No	Rosseland opacity additive offset. Powerlaw only.
kP_offset	double	0.0	No	Planck opacity additive offset. Powerlaw only.
rho_exp	double	—	No	Density exponent for powerlaw opacity.
kR	double	—	No	Rosseland mean opacity (cm^2/g). Required for constant and powerlaw.

floors

Key	Type	Default	Required	Description
rosseland	double	0.001	No	Rosseland floor value. Used with constant floor model.
planck	double	0.001	No	Planck floor value. Used with constant floor model.
env_planck	double	0.01	No	Envelope Planck floor. Used with core_envelope model.
env_rosseland	double	0.01	No	Envelope Rosseland floor. Used with core_envelope model.
core_rosseland	double	0.24	No	Core Rosseland floor. Used with core_envelope model.
core_planck	double	0.24	No	Core Planck floor. Used with core_envelope model.
type	string	core_envelope	No	Opacity floor model. Options: ‘core_envelope’, ‘constant’.

config.output

Key	Type	Default	Required	Description
dt_init	double	1.000000e-16	No	Initial timestep. Must be > 0.
dt_hdf5	double	—	No	Time interval between HDF5 outputs. Default: t_end / 100.
dt_fixed	double	—	No	Fixed timestep override. Optional.
ncycle_out	double	100	No	Number of cycles between stdout output.
dt_init_frac	double	1.05	No	Initial timestep growth factor. Must be > 1.

history

Key	Type	Default	Required	Description
fn	string	athelas.hst	No	History output filename.
dt	double	—	No	Time interval between history writes. Default: dt_hdf5 / 10.

config.physics

Key	Type	Default	Required	Description
engine	bool	false	No	Enable energy injection engine.
radiation	bool	false	No	Enable radiation transport.
composition	bool	false	No	Enable multi-species composition.
gravity	bool	false	No	Enable gravitational source terms.
heating	bool	false	No	Enable nuclear heating sources.
ionization	bool	false	No	Enable Saha ionization. Requires composition = true.

config.problem

Key	Type	Default	Required	Description
xl	double	—	No	Left boundary of the domain.
name	string	—	No	Unique identifier for this simulation problem.
xr	double	—	No	Right boundary of the domain. Must be > xl.
geometry	string	—	No	Domain geometry. Options: ‘planar’, ‘spherical’.
cfl	double	—	No	CFL double for timestep control. Must be > 0.
params	—	—	No	Problem-specific parameters. Validated by the problem generator.
grid_type	string	—	No	Grid spacing type. Options: ‘uniform’, ‘logarithmic’.
t_end	double	—	No	End time of the simulation.
nx	double	—	No	Number of grid cells. Must be > 0.
nlim	double	-1	No	Maximum double of cycles. -1 for unlimited.

config.radiation

limiter

Key	Type	Default	Required	Description
characteristic	bool	false	No	Enable characteristic limiting. Currently unsupported for radiation.
b_tvd	double	1.0	No	TVD parameter b. Used with minmod limiter.
tci_val	double	—	No	Troubled-cell indicator threshold.
m_tvb	double	0.0	No	TVB parameter M. Used with minmod limiter.
type	string	minmod	No	Limiter type. Options: ‘minmod’, ‘weno’.
gamma_i	double	—	No	WENO central weight. Required for WENO limiter.
gamma_l	double	—	No	WENO left weight. Inferred from gamma_i if omitted.
gamma_r	double	—	No	WENO right weight. Inferred from gamma_i if omitted.
do_limiter	bool	true	No	Enable slope limiter for radiation.
weno_r	double	2.0	No	WENO smoothness exponent. Must be > 0.
tci_opt	bool	false	No	Enable troubled-cell indicator.

config.time

Key	Type	Default	Required	Description
integrator	string	—	No	Time integration method. E.g. ‘IMEX_SSPRK11’, ‘IMEX_ARK32_ESDIRK’.