swiftest.Simulation.set_parameter

swiftest.Simulation.set_parameter#

Simulation.set_parameter(**kwargs)[source]#

Setter for all possible parameters. This will call each of the specialized setters using keyword arguments.

If no arguments are passed, then either values from the param_file or default values will be used.

Parameters:

**kwargs (dict) – See list of valid parameters and their defaults below
param_file (str, path-like, or file-like, default None) – Name of the parameter input file that will be passed to the integrator. If passed, then the file will be read in and the parameters set from them, but can be overriden by any explicit arguments
codename ({“Swiftest”, “Swifter”, “Swift”}, default “Swiftest”) – Name of the n-body code that will be used. Parameter input file equivalent is None
integrator ({“symba”,”rmvs”,”whm”,”helio”}, default “symba”) – Name of the n-body integrator that will be used when executing a run. Parameter input file equivalent is None
t0 (float, default 0.0) – The reference time for the start of the simulation. Defaults is 0.0. Parameter input file equivalent is T0
tstart (float, default 0.0) – The start time for a restarted simulation. For a new simulation, tstart will be set to t0 automatically. Parameter input file equivalent is TSTART
tstop (float, optional) – The stopping time for a simulation. tstop must be greater than tstart. Parameter input file equivalent is TSTOP
dt (float, optional) – The step size of the simulation. dt must be less than or equal to tstop-tstart. Parameter input file equivalent is DT
istep_out (int, optional) – The number of time steps between output saves to file. Only istep_out or tstep_out can be set. Parameter input file equivalent is ISTEP_OUT
tstep_out (float, optional) – The approximate time between when outputs are written to file. Passing this computes:
```
istep_out = floor(tstep_out / dt)
```
Only istep_out or tstep_out can be set. tstep_out must be less than tstop. Parameter input file equivalent is None
nstep_out (int, optional) – The total number of times that outputs are written to file. Passing this allows for a geometric progression of output steps:
```
TSTART, f**0 * TSTEP_OUT, f**1 * TSTEP_OUT, f**2 * TSTEP_OUT, ..., f ** (nstep_out - 1) * TSTEP_OUT
```
where f is a factor that can stretch (or shrink) the time between outputs. Setting:
```
nstep_out = int((tstart - tstop) / (tstep_out))
```
is equivalent to the standard linear output (i.e. f==1) and is the same as not passing anything for this argument. Passing nstep_out requires passing either istep_out or tstep_out as well.
dump_cadence (int, optional) – The number of output steps (given by istep_out) between when the saved data is dumped to a file. Setting it to 0 is equivalent to only dumping data to file at the end of the simulation. Default value is 10. Parameter input file equivalent is DUMP_CADENCE
init_cond_file_type ({“NETCDF_DOUBLE”, “NETCDF_FLOAT”, “ASCII”}, default “NETCDF_DOUBLE”) – The file type containing initial conditions for the simulation.
- “NETCDF_DOUBLE” A single initial conditions input file in NetCDF file format of type NETCDF_DOUBLE.
- “NETCDF_FLOAT” A single initial conditions input file in NetCDF file format of type NETCDF_FLOAT.
- “ASCII” Three initial conditions files in ASCII format. The individual files define the central body,
massive body, and test particle initial conditions. Parameter input file equivalent is IN_TYPE
init_cond_file_name (str, path-like, or dict, optional) – Name of the input initial condition file or files. Whether to pass a single file name or a dictionary depends on the argument passed to init_cond_file_type. If init_cond_file_type={“NETCDF_DOUBLE”,”NETCDF_FLOAT”}, then this will be a single file name. If init_cond_file_type=”ASCII” then this must be a dictionary where:
```
init_cond_file_name = {
    "CB" - [path to central body initial conditions file] (Swiftest only),
    "PL" - [path to massive body initial conditions file],
    "TP" - [path to test particle initial conditions file] }
```
If no file name is provided then the following default file names will be used.
- “NETCDF_DOUBLE”, “NETCDF_FLOAT” init_cond_file_name = “init_cond.nc”
- “ASCII” init_cond_file_name = {“CB” : “cb.in”, “PL” : “pl.in”, “TP” : “tp.in”}
Parameter input file equivalent is NC_IN, CB_IN, PL_IN, TP_IN
init_cond_format ({“EL”, “XV”}, default “XV”) – Indicates whether the input initial conditions are given as orbital elements or cartesian position and velocity vectors. If codename is “Swift” or “Swifter”, EL initial conditions are converted to XV. Parameter input file equivalent is IN_FORM
output_file_type ({“NETCDF_DOUBLE”, “NETCDF_FLOAT”,”REAL4”,”REAL8”,”XDR4”,”XDR8”}, default “NETCDF_DOUBLE”) – The file type for the outputs of the simulation. Compatible file types depend on the codename argument.
- Swiftest - Only “NETCDF_DOUBLE” or “NETCDF_FLOAT” supported.
- Swifter - Only “REAL4”,”REAL8”,”XDR4” or “XDR8” supported.
- Swift - Only “REAL4” supported.
Parameter input file equivalent is OUT_TYPE
output_file_name (str or path-like, optional) – Name of output file to generate. If not supplied, then one of the default file names are used, depending on the value passed to output_file_type. The default is “data.nc”. Parameter input file equivalent is BIN_OUT
output_format ({“XV”,”XVEL”}, default “XVEL”) – Specifies the format for the data saved to the output file. If “XV” then cartesian position and velocity vectors for all bodies are stored. If “XVEL” then the orbital elements are also stored. Parameter input file equivalent is OUT_FORM
simdir (PathLike, optional) – Directory where simulation data will be stored, including the parameter file, initial conditions file, output file
MU (str, optional) – The mass unit system to use. Case-insensitive valid options are
- “Msun” - Solar mass
- “Mearth” - Earth mass
- “kg” - kilograms
- “g”,”gm” - grams
DU (str, optional) – The distance unit system to use. Case-insensitive valid options are
- “AU” - Astronomical Unit
- “Rearth” - Earth radius
- “km” - kilometer
- “m” - meter
- “cm” - centimeter
TU (str, optional) – The time unit system to use. Case-insensitive valid options are
- “y”,”YR”,”year”,”years” - Year
- “d”,”day”,”days” - Julian day
- “s”,”sec”,”seconds”,”second” - second
Parameter input file equivalent is None
MU2KG (float, optional) – The conversion factor to multiply by the mass unit that would convert it to kilogram. Setting this overrides MU Parameter input file equivalent is MU2KG
DU2M (float, optional) – The conversion factor to multiply by the distance unit that would convert it to meter. Setting this overrides DU Parameter input file equivalent is DU2M
TU2S (float, optional) – The conversion factor to multiply by the time unit that would convert it to seconds. Setting this overrides TU Parameter input file equivalent is TU2S
MU_name (str, optional) – The name of the mass unit. When setting one of the standard units via MU a name will be automatically set for the unit, so this argument will override the automatic name. Parameter input file equivalent is None
DU_name (str, optional) – The name of the distance unit. When setting one of the standard units via DU a name will be automatically set for the unit, so this argument will override the automatic name. Parameter input file equivalent is None
TU_name (str, optional) – The name of the time unit. When setting one of the standard units via TU a name will be automatically set for the unit, so this argument will override the automatic name. Parameter input file equivalent is None
rmin (float, default value is the radius of the central body in the unit system defined by the unit input arguments.) – Minimum distance of the simulation Parameter input file equivalent are CHK_QMIN, CHK_RMIN, CHK_QMIN_RANGE[0]
rmax (float, default value is 10000 AU in the unit system defined by the unit input arguments.) – Maximum distance of the simulation (CHK_RMAX, CHK_QMIN_RANGE[1]) Parameter input file equivalent are CHK_RMAX, CHK_QMIN_RANGE[1]
qmin_coord (str, {“HELIO”, “BARY”}, default “HELIO”) – coordinate frame to use for checking the minimum periapsis distance Parameter input file equivalent is QMIN_COORD
mtiny (float, optional) – The minimum mass of fully interacting bodies. Bodies below this mass interact with the larger bodies, but not each other (SyMBA only). Only mtiny or gmtiny is accepted, not both. Parameter input file equivalent is None
gmtiny (float, optional) – The minimum G*mass of fully interacting bodies. Bodies below this mass interact with the larger bodies, but not each other (SyMBA only). Only mtiny or gmtiny is accepted, not both. Parameter input file equivalent is GMTINY
close_encounter_check (bool, default True) – Check for close encounters between bodies. If set to True, then the radii of massive bodies must be included in initial conditions. Parameter input file equivalent is CHK_CLOSE
encounter_save ({“NONE”,”TRAJECTORY”,”CLOSEST”, “BOTH”}, default “NONE”) – Indicate if and how encounter data should be saved. If set to “TRAJECTORY”, the position and velocity vectors of all bodies undergoing close encounters are saved at each intermediate step to the encounter files. If set to “CLOSEST”, the position and velocities at the point of closest approach between pairs of bodies are computed and stored to the encounter files. If set to “BOTH”, then this stores the values that would be computed in “TRAJECTORY” and “CLOSEST”. If set to “NONE” no trajectory information is saved. WARNING - Enabling this feature could lead to very large files.
general_relativity (bool, default True) – Include the post-Newtonian correction in acceleration calculations. Parameter input file equivalent is “GR”
collision_model ({“MERGE”,”BOUNCE”,”FRAGGLE”}, default “MERGE”) – This is used to set the collision/fragmentation model. This argument only applies to Swiftest-SyMBA simulations and will be ignored otherwise. Parameter input file equivalent is “COLLISION_MODEL”
minimum_fragment_gmass (float, optional) – If fragmentation is turned on, this sets the mimimum G*mass of a collisional fragment that can be generated if a fragmentation model is enabled. Ignored otherwise. Only set one of minimum_fragment_gmass or minimum_fragment_mass Parameter input file equivalent is None
minimum_fragment_mass (float, optional) – If fragmentation is turned on, this sets the mimimum mass of a collisional fragment that can be generated. if a fragmentation model is enabled. Ignored otherwise Only set one of minimum_fragment_gmass or minimum_fragment_mass Parameter input file equivalent is MIN_GMFRAG
nfrag_reduction (float, optional) – If fragmentation is turned on, this is a reduction factor used to limit the number of fragments generated in a collision. For instance, if the SFD of the collision would generated 300 fragments above the minimum_fragment_mass, then a value of nfrag_reduction = 30.0 would reduce it to 10. Currently only used by the Fraggle collision model.
rotation (bool, default True) – If set to True, this turns on rotation tracking and radius, rotation vector, and moments of inertia values must be included in the initial conditions. This argument only applies to Swiftest-SyMBA simulations. It will be ignored otherwise. Parameter input file equivalent is ROTATION
compute_conservation_values (bool, default True for SyMBA, otherwise False) – Turns on the computation of energy, angular momentum, and mass conservation and reports the values every output step of a running simulation. Parameter input file equivalent is ENERGY
extra_force (bool, default False) – Turns on user-defined force function. Parameter input file equivalent is EXTRA_FORCE
big_discard (bool, default False) – Includes big bodies when performing a discard (Swifter only) Parameter input file equivalent is BIG_DISCARD
rhill_present (bool, default False) – Include the Hill’s radius with the input files . Parameter input file equivalent is RHILL_PRESENT
restart (bool, default False) – If true, will restart an old run. The file given by output_file_name must exist before the run can execute. If false, will start a new run. If the file given by output_file_name exists, it will be replaced when the run is executed. Parameter input file equivalent is OUT_STAT
interaction_loops ({“TRIANGULAR”,”FLAT”}, default “TRIANGULAR”) – Swiftest Experimental feature Specifies which algorithm to use for the computation of body-body gravitational forces.
- “TRIANGULAR” - Upper-triangular double-loops.
- “FLAT” - Body-body interation pairs are flattened into a 1-D array.
Parameter input file equivalent is INTERACTION_LOOPS
encounter_check_loops ({“TRIANGULAR”,”SORTSWEEP”}, default “TRIANGULAR”) – Swiftest Experimental feature Specifies which algorithm to use for checking whether bodies are in a close encounter state or not.
- “TRIANGULAR” - Upper-triangular double-loops.
- “SORTSWEEP” - A Sort-Sweep algorithm is used to reduce the population of potential close encounter bodies. This algorithm is still in development, and does not necessarily speed up the encounter checking. Use with caution.
Parameter input file equivalent is ENCOUNTER_CHECK
dask (bool, default False) – Use Dask to lazily load data (useful for very large datasets)
coarray (bool, default False) – If true, will employ Coarrays on test particle structures to run in single program/multiple data parallel mode. In order to use this capability, Swiftest must be compiled for Coarray support. Only certain integrators can use Coarrays. RMVS, WHM, Helio are all compatible, but SyMBA is not, due to the way tp-pl close encounters are handeled.
verbose (bool, default False) – If set to True, then more information is printed by Simulation methods as they are executed. Setting to False suppresses most messages other than errors and some warnings.
seed (ArrayLike of int, optional) – Seed for the random number generator. If not set, then a random seed is generated. Parameter input file equivalent is SEED

Returns:

param (dict) – A dictionary of all Simulation parameters that changed

swiftest.Simulation.set_parameter

Contents

swiftest.Simulation.set_parameter#