Runtime parameters

This document lists all of the runtime parameters in Quokka that are set using the AMReX ParmParse object. Users can set these via the input file or by using command-line arguments.

General

These parameters are read in the AMRSimulation<problem_t>::readParameters() function in src/simulation.hpp.

Table of runtime parameters.

Parameter Name	Type	Description
max_timesteps	Integer	The maximum number of time steps for the simulation.
cfl	Float	Sets the CFL number for the simulation.
amr_interpolation_method	Integer	Selects the method (piecewise constant or piecewise linear with limiters) used to interpolate from coarse to fine AMR levels. Except for debugging, this should not be changed.
stop_time	Float	The simulation time at which to stop evolving the simulation.
ascent_interval	Integer	The number of coarse timesteps between Ascent outputs.
plotfile_interval	Integer	The number of coarse timesteps between plotfile outputs.
plottime_interval	Float	The time interval (in simulated time) between plotfile outputs.
projection_interval	Integer	The number of coarse timesteps between 2D projection outputs.
statistics_interval	Integer	The number of coarse timesteps between statistics outputs.
checkpoint_interval	Float	The number of coarse timesteps between checkpoint outputs.
checkpointtime_interval	Float	The time interval (in simulated time) between checkpoint outputs.
do_reflux	Integer	This turns on refluxing at coarse-fine boundaries (1) or turns it off (0). Except for debugging, this should always be on when AMR is used.
do_tracers	Integer	This turns on tracer particles. They are initialized one-per-cell and they follow the fluid velocity. Default: 0 (off).
suppress_output	Integer	If set to 1, this disables output to stdout while the simulation is running.
derived_vars	String	A list of the names of derived variables that should be included in the plotfile and Ascent outputs.
regrid_interval	Integer	The number of timesteps between AMR regridding.
density_floor	Float	The minimum density value allowed in the simulation. Enforced through EnforceLimits.
temperature_ceiling	Float	The ceiling on temperature values in the simulation. Enforced through EnforceLimits.
speed_ceiling	Float	The ceiling on the absolute value of the fluid velocity in the simulation. Enforced through EnforceLimits.
max_walltime	String	The maximum walltime for the simulation in the format DD:HH:SS (days/hours/seconds). After 90% of this walltime elapses, the simulation will automatically stop and exit.

Hydrodynamics

These parameters are read in the RadhydroSimulation<problem_t>::readParmParse() function in src/RadhydroSimulation.hpp.

Table of hydrodynamics parameters.

Parameter Name	Type	Description
hydro.low_level_debugging_output	Integer	If set to 1, turns on low-level debugging output for each RK stage. Warning: this writes an enormous volume of data to disk! This should only be used for debugging. Default: 0.
hydro.rk_integrator_order	Integer	Determines the order of the RK integrator used. Can be set to 1 (Forward Euler) or 2 (RK2-SSP, also known as Heun’s method). Default: 2. This should only be changed for debugging.
hydro.reconstruction_order	Integer	Determines the order of spatial reconstruction algorithm used. Can be set to 1 (piecewise constant), 2 (piecewise linear; PLM), or 3 (piecewise parabolic; PPM). Default: 3 (PPM).
hydro.use_dual_energy	Integer	If set to 1, the code evolves an auxiliary internal energy variable in order to correctly evolve high-mach flows. This should only be disabled (0) for debugging. Default: 1.
hydro.abort_on_fofc_failure	Integer	If set to 1, the code aborts when first-order flux correction fails to yield a physical state (positive density and pressure). This should only be disabled (0) for debugging.
hydro.artificial_viscosity_coefficient	Float	This is the linear artificial viscosity coefficient used in the artificial viscosity term added to the flux. This is the same parameter as defined in the original PPM paper. Default: 0.

Radiation

These parameters are read in the RadhydroSimulation<problem_t>::readParmParse() function in src/RadhydroSimulation.hpp.

Table of radiation parameters.

Parameter Name	Type	Description
radiation.reconstruction_order	Integer	Determines the order of spatial reconstruction algorithm used. Can be set to 1 (piecewise constant), 2 (piecewise linear; PLM), or 3 (piecewise parabolic; PPM). Default: 3 (PPM).
radiation.cfl	Float	Sets the CFL number for the radiation advance. This is independent of the hydro CFL number.

Optically-thin radiative cooling

These parameters are read in the RadhydroSimulation<problem_t>::readParmParse() function in src/RadhydroSimulation.hpp.

Table of optically-thin radiative cooling parameters.

Parameter Name	Type	Description
cooling.enabled	Integer	If set to 1, turns on optically-thin radiative cooling as a Strang-split source term. Default: 0 (disabled).
cooling.read_tables_even_if_disabled	Integer	If set to 1, reads the cooling tables even if the cooling module is disabled.
cooling.grackle_data_file	String	The path to the cooling tables in Grackle-compatible HDF5 format.