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Matthieu Schaller authoredMatthieu Schaller authored
parameter_example.yml 39.70 KiB
# Define some meta-data about the simulation
MetaData:
run_name: Name of the sim in less than 256 characters. # The name of the simulation. This is written into the snapshot headers.
# Define the system of units to use internally.
InternalUnitSystem:
UnitMass_in_cgs: 1 # Grams
UnitLength_in_cgs: 1 # Centimeters
UnitVelocity_in_cgs: 1 # Centimeters per second
UnitCurrent_in_cgs: 1 # Amperes
UnitTemp_in_cgs: 1 # Kelvin
# Values of some physical constants
PhysicalConstants:
G: 6.67408e-8 # (Optional) Overwrite the value of Newton's constant used internally by the code.
# Cosmological parameters
Cosmology:
h: 0.6777 # Reduced Hubble constant
a_begin: 0.0078125 # Initial scale-factor of the simulation
a_end: 1.0 # Final scale factor of the simulation
Omega_m: 0.307 # Matter density parameter
Omega_lambda: 0.693 # Dark-energy density parameter
Omega_b: 0.0482519 # Baryon density parameter
Omega_r: 0. # (Optional) Radiation density parameter
w_0: -1.0 # (Optional) Dark-energy equation-of-state parameter at z=0.
w_a: 0. # (Optional) Dark-energy equation-of-state time evolution parameter.
# Parameters for the hydrodynamics scheme
SPH:
resolution_eta: 1.2348 # Target smoothing length in units of the mean inter-particle separation (1.2348 == 48Ngbs with the cubic spline kernel).
CFL_condition: 0.1 # Courant-Friedrich-Levy condition for time integration.
use_mass_weighted_num_ngb: 0 # (Optional) Are we using the mass-weighted definition of the number of neighbours?
h_tolerance: 1e-4 # (Optional) Relative accuracy of the Netwon-Raphson scheme for the smoothing lengths.
h_max: 10. # (Optional) Maximal allowed smoothing length in internal units. Defaults to FLT_MAX if unspecified.
h_min_ratio: 0. # (Optional) Minimal allowed smoothing length in units of the softening. Defaults to 0 if unspecified.
max_volume_change: 1.4 # (Optional) Maximal allowed change of kernel volume over one time-step.
max_ghost_iterations: 30 # (Optional) Maximal number of iterations allowed to converge towards the smoothing length.
particle_splitting: 1 # (Optional) Are we splitting particles that are too massive (default: 0)
particle_splitting_mass_threshold: 7e-4 # (Optional) Mass threshold for particle splitting (in internal units)
initial_temperature: 0 # (Optional) Initial temperature (in internal units) to set the gas particles at start-up. Value is ignored if set to 0.
minimal_temperature: 0 # (Optional) Minimal temperature (in internal units) allowed for the gas particles. Value is ignored if set to 0.
H_mass_fraction: 0.755 # (Optional) Hydrogen mass fraction used for initial conversion from temp to internal energy. Default value is derived from the physical constants.
H_ionization_temperature: 1e4 # (Optional) Temperature of the transition from neutral to ionized Hydrogen for primoridal gas.
viscosity_alpha: 0.8 # (Optional) Override for the initial value of the artificial viscosity. In schemes that have a fixed AV, this remains as alpha throughout the run.
viscosity_alpha_max: 2.0 # (Optional) Maximal value for the artificial viscosity in schemes that allow alpha to vary.
viscosity_alpha_min: 0.1 # (Optional) Minimal value for the artificial viscosity in schemes that allow alpha to vary.
viscosity_length: 0.1 # (Optional) Decay length for the artificial viscosity in schemes that allow alpha to vary.
diffusion_alpha: 0.0 # (Optional) Override the initial value for the thermal diffusion coefficient in schemes with thermal diffusion.
diffusion_beta: 0.01 # (Optional) Override the decay/rise rate tuning parameter for the thermal diffusion.
diffusion_alpha_max: 1.0 # (Optional) Override the maximal thermal diffusion coefficient that is allowed for a given particle.
diffusion_alpha_min: 0.0 # (Optional) Override the minimal thermal diffusion coefficient that is allowed for a given particle.
# Parameters of the stars neighbour search
Stars:
resolution_eta: 1.2348 # (Optional) Target smoothing length in units of the mean inter-particle separation (1.2348 == 48Ngbs with the cubic spline kernel). Defaults to the SPH value.
h_tolerance: 1e-4 # (Optional) Relative accuracy of the Netwon-Raphson scheme for the smoothing lengths. Defaults to the SPH value.
max_ghost_iterations: 30 # (Optional) Maximal number of iterations allowed to converge towards the smoothing length. Defaults to the SPH value.
max_volume_change: 1.4 # (Optional) Maximal allowed change of kernel volume over one time-step. Defaults to the SPH value.
overwrite_birth_time: 0 # (Optional) Do we want to overwrite the birth time of the stars read from the ICs? (default: 0).
birth_time: -1 # (Optional) Initial birth times of *all* the stars to be used if we are overwriting them. (-1 means the stars remain inactive feedback-wise througout the run).
# Parameters for the self-gravity scheme
Gravity:
mesh_side_length: 128 # Number of cells along each axis for the periodic gravity mesh.
eta: 0.025 # Constant dimensionless multiplier for time integration.
theta: 0.7 # Opening angle (Multipole acceptance criterion).
comoving_DM_softening: 0.0026994 # Comoving Plummer-equivalent softening length for DM particles (in internal units).
max_physical_DM_softening: 0.0007 # Maximal Plummer-equivalent softening length in physical coordinates for DM particles (in internal units).
comoving_baryon_softening: 0.0026994 # Comoving Plummer-equivalent softening length for baryon particles (in internal units).