Config Files

lst_tools uses a TOML-style configuration file (lst.cfg) to control the LST workflow.

Creating a Config File

Generate a default configuration:

lst-tools init

Geometry presets are available:

lst-tools init --geometry cone

Configuration Sections

Top-Level

Key	Type	Default	Description
input_file	str	"base_flow.hdf5"	Path to the HDF5 base flow file
lst_exe	str	"lst.x"	Path to the LST solver executable

[flow_conditions]

Flow conditions for the LST analysis:

Key	Type	Default	Description
mach	float	—	Freestream Mach number
re1	float	—	Unit Reynolds number [1/m]
gamma	float	1.4	Ratio of specific heats
cp	float	1005.025	Specific heat at constant pressure [J/(kg K)]
cv	float	717.875	Specific heat at constant volume [J/(kg K)]
rgas	float	287.15	Specific gas constant [J/(kg K)]
pres_0	float	—	Stagnation pressure [Pa]
temp_0	float	—	Stagnation temperature [K]
pres_inf	float	—	Freestream pressure [Pa]
temp_inf	float	—	Freestream temperature [K]
dens_inf	float	—	Freestream density [kg/m^3]
uvel_inf	float	—	Freestream velocity [m/s]
visc_law	int	0	Viscosity law index

[geometry]

Geometry description:

Key	Type	Default	Description
type	str	—	Geometry kind (e.g., cone, flat plate)
theta_deg	float	—	Half-angle [deg]
r_nose	float	—	Nose radius [m]
l_ref	float	1	Reference length [m]
is_body_fitted	bool	false	Whether the grid is body-fitted

[meanflow_conversion]

Controls for base flow conversion:

Key	Type	Default	Description
i_s	int	0	Start index
i_e	int	—	End index
d_i	int	1	Index stride
set_v_zero	bool	true	Zero out wall-normal velocity

[lst.solver]

LST solver settings:

Key	Type	Default	Description
type	int	1	Solver type
is_simplified	bool	false	Use simplified equations
alpha_i_threshold	float	-100.0	Threshold used in alpha_i filtering
generalized	int	0	Generalized eigenproblem switch
spatial_temporal	int	1	Spatial (1) or temporal (0) analysis
energy_formulation	int	1	Energy equation formulation

[lst.options]

Additional solver options:

Key	Type	Default	Description
geometry_switch	int	—	Geometry mode switch
longitudinal_curvature	int	0	Enable longitudinal curvature terms

[lst.params]

LST calculation parameters:

Key	Type	Default	Description
ny	int	150	Number of wall-normal grid points
yl_in	float	0.0	Initial wall-normal location
tol_lst	float	1e-5	Convergence tolerance
max_iter	int	15	Maximum iterations
x_s	float	—	Start streamwise location
x_e	float	—	End streamwise location
i_step	int	—	Streamwise index stride
tracking_dir	int	1	Tracking direction flag
f_min	float	—	Minimum frequency [Hz]
f_max	float	—	Maximum frequency [Hz]
d_f	float	—	Frequency step [Hz]
f_init	float	0.0	Tracking initialization frequency [Hz]
beta_s	float	—	Start spanwise wavenumber
beta_e	float	—	End spanwise wavenumber
d_beta	float	—	Spanwise wavenumber step
beta_init	float	0.0	Tracking initialization spanwise wavenumber
alpha_0	complex	(0, 0)	Initial complex alpha guess

[lst.io]

LST input/output file paths:

Key	Type	Default	Description
baseflow_input	str	"meanflow.bin"	Converted base flow file
solution_output	str	"growth_rate.dat"	LST output file

[hpc]

HPC job settings:

Key	Type	Default	Description
account	str	—	Account/allocation name
nodes	int	—	Number of nodes
time	str	—	Wall time
partition	str	—	Partition/queue name
extra_env	table	—	Extra environment variables injected into run scripts

[processing]

Tracking post-processing controls:

Key	Type	Default	Description
interpolate	bool	false	Enable parabolic peak interpolation
gate_tol	float	0.10	Ridge-tracking gating tolerance
min_valid	int	40	Minimum valid points for ridge acceptance
peak_order	int	1	Local peak search order

Programmatic Access

from lst_tools.config import read_config, write_config

# read as typed dataclass
config = read_config("lst.cfg")

# modify values
config.lst.params.ny = 200

# write to TOML
write_config("lst_modified.cfg", overwrite=True, cfg_data=config.to_dict())