Command line options
SWIFT requires a number of runtime options to run and get any sensible output.
For instance, just running the swift binary will not use any SPH or gravity;
the particles will just sit still!
Below is a list of the command line options and when they should be used. The same list
can be found by typing ./swift -h:
-h, --help show this help message and exit
Simulation options:
-b, --feedback Run with stars feedback.
-c, --cosmology Run with cosmological time integration.
--temperature Run with temperature calculation.
-C, --cooling Run with cooling (also switches on --temperature).
-D, --drift-all Always drift all particles even the ones
far from active particles. This emulates
Gadget-[23] and GIZMO's default behaviours.
-F, --star-formation Run with star formation.
-g, --external-gravity Run with an external gravitational potential.
-G, --self-gravity Run with self-gravity.
-M, --multipole-reconstruction Reconstruct the multipoles every time-step.
-s, --hydro Run with hydrodynamics.
-S, --stars Run with stars.
-B, --black-holes Run with black holes.
-k, --sinks Run with sink particles.
-u, --fof Run Friends-of-Friends algorithm to
perform black hole seeding.
--lightcone Generate lightcone outputs.
-x, --velociraptor Run with structure finding.
--line-of-sight Run with line-of-sight outputs.
--limiter Run with time-step limiter.
--sync Run with time-step synchronization
of particles hit by feedback events.
--csds Run with the Continuous Simulation Data
Stream (CSDS).
-R, --radiation Run with radiative transfer.
--power Run with power spectrum outputs.
Simulation meta-options:
--quick-lyman-alpha Run with all the options needed for the
quick Lyman-alpha model. This is equivalent
to --hydro --self-gravity --stars --star-formation
--cooling.
--eagle Run with all the options needed for the
EAGLE model. This is equivalent to --hydro
--limiter --sync --self-gravity --stars
--star-formation --cooling --feedback
--black-holes --fof.
--gear Run with all the options needed for the
GEAR model. This is equivalent to --hydro
--limiter --sync --self-gravity --stars
--star-formation --cooling --feedback.
--agora Run with all the options needed for the
AGORA model. This is equivalent to --hydro
--limiter --sync --self-gravity --stars
--star-formation --cooling --feedback.
Control options:
-a, --pin Pin runners using processor affinity.
--nointerleave Do not interleave memory allocations across
NUMA regions.
-d, --dry-run Dry run. Read the parameter file, allocates
memory but does not read the particles
from ICs. Exits before the start of time
integration. Checks the validity of
parameters and IC files as well as memory
limits.
-e, --fpe Enable floating-point exceptions (debugging
mode).
-f, --cpu-frequency=<str> Overwrite the CPU frequency (Hz) to be
used for time measurements.
-n, --steps=<int> Execute a fixed number of time steps.
When unset use the time_end parameter
to stop.
-o, --output-params=<str> Generate a parameter file with the options
for selecting the output fields.
-P, --param=<str> Set parameter value, overiding the value
read from the parameter file. Can be used
more than once {sec:par:value}.
-r, --restart Continue using restart files.
-t, --threads=<int> The number of task threads to use on each
MPI rank. Defaults to 1 if not specified.
--pool-threads=<int> The number of threads to use on each MPI
rank for the threadpool operations.
Defaults to the numbers of task threads
if not specified.
-T, --timers=<int> Print timers every time-step.
-v, --verbose=<int> Run in verbose mode, in MPI mode 2 outputs
from all ranks.
-y, --task-dumps=<int> Time-step frequency at which task graphs
are dumped.
--cell-dumps=<int> Time-step frequency at which cell graphs
are dumped.
-Y, --threadpool-dumps=<int> Time-step frequency at which threadpool
tasks are dumped.
--dump-tasks-threshold=<flt> Fraction of the total step's time spent
in a task to trigger a dump of the task plot
on this step
See the file examples/parameter_example.yml for an example of parameter file.