AREPO is a parallel moving-mesh code for hydrodynamical cosmological simulations. It is a flexible code that can be applied to a variety of different types of simulations, offering a variety of physics solvers and postprocessing algorithms.
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AREPO is a massively parallel code for gravitational n-body
systems and hydrodynamics, both on Newtonian as well as
cosmological background. It is a flexible code that can be
applied to a variety of different types of simulations, offering
a number of sophisticated simulation algorithms. An description
of the numerical algorithms employed by the code is given in the
original code papers (Springel 2010, MNRAS, 401, 791;
Pakmor et al. 2011, MNRAS, 418, 1392; Pakmor and Springel 2013,
MNRAS, 432, 176; Pakmor et al. 2016, MNRAS,455,1134) and the
release paper of this version (Weinberger et al. 2019).
A user guide can be found under `/documentation`, which also
includes a 'getting started' section, which is recommended for
new users. An html version of the user guide can be created using
sphinx (https://www.sphinx-doc.org) by typing
cd ./documentation/
make html
and displayed by opening `./documentation/build/html/index.html`.
A full version of the user guide is also available on the Arepo
#--------------------------------------- Basic operation mode of code; default: 3d with 6 particle types; type 0: gas >0: only gravitationally interacting
#ENFORCE_JEANS_STABILITY_OF_CELLS # this imposes an adaptive floor for the temperature
#USE_SFR # Star formation model, turning dense gas into collisionless partices
#SFR_KEEP_CELLS # Do not distroy cell out of which a star has formed
#--------------------------------------- Gravity treatment; default: no gravity
#SELFGRAVITY # gravitational intraction between simulation particles/cells
#HIERARCHICAL_GRAVITY # use hierarchical splitting of the time integration of the gravity
#CELL_CENTER_GRAVITY # uses geometric centers to calculate gravity of cells, only possible with HIERARCHICAL_GRAVITY
#NO_GAS_SELFGRAVITY # switch off gas self-gravity in tree
#GRAVITY_NOT_PERIODIC # gravity is not treated periodically
#ALLOW_DIRECT_SUMMATION # Performed direct summation instead of tree-based gravity if number of active particles < DIRECT_SUMMATION_THRESHOLD (= 3000 unless specified differently here)
#DIRECT_SUMMATION_THRESHOLD=1000 # Overrides maximum number of active particles for which direct summation is performed instead of tree based calculation
#EXACT_GRAVITY_FOR_PARTICLE_TYPE=4 #N-squared fashion gravity for a small number of particles of the given type
#EVALPOTENTIAL # computes gravitational potential
#RANDOMIZE_DOMAINCENTER # random displacement to position of domain center; avoids correlated force-errors, important mainly for isolated systems (which otherwise might start to drift in some direction).
#--------------------------------------- TreePM Options; default: no Particle-Mesh
#PMGRID=512 # Enables particle mesh; number of cells used for grid in each dimension
#ASMTH=1.25 # This can be used to override the value assumed for the scale that defines the long-range/short-range force-split in the TreePM algorithm. The default value is 1.25, in mesh-cells.
#RCUT=6.0 # This can be used to override the maximum radius in which the short-range tree-force is evaluated (in case the TreePM algorithm is used). The default value is 4.5, given in mesh-cells.
#PM_ZOOM_OPTIMIZED # Particle-mesh calculation that is optimized for cosmological zoom simulations; disable for cosmological volume simulations.
#PLACEHIGHRESREGION=2 # Places a second, high-resolution PM grid; number encodes high-res particle types from which the extent of this second PM grid is calculated.
#ENLARGEREGION=1.1 # Factor by which high res region is increased with respect to max-min position of high-res particles
#GRIDBOOST=2 # Factor by which PMGRID is increased in non-periodic (or high res) PM calculation (if not set, code uses 2)
#FFT_COLUMN_BASED # Use column-based FFT; slightly slower, but necessary to achieve good load-balancing if number of tasks larger than PMGRID (usually the case for very large runs)
#DOUBLEPRECISION=1 # Mode of double precision: not defined: single; 1: full double precision 2: mixed, 3: mixed, fewer single precisions; unless short of memory, use 1.
#DOUBLEPRECISION_FFTW # FFTW calculation in double precision
#OUTPUT_IN_DOUBLEPRECISION # snapshot files will be written in double precision
#INPUT_IN_DOUBLEPRECISION # initial conditions are in double precision
#OUTPUT_COORDINATES_IN_DOUBLEPRECISION # will always output coordinates in double precision
#NGB_TREE_DOUBLEPRECISION # if this is enabled, double precision is used for the neighbor node extension
#--------------------------------------- On the fly FOF groupfinder
#FOF # enable FoF output
#FOF_PRIMARY_LINK_TYPES=2 # 2^type for the primary dark matter type
#FOF_SECONDARY_LINK_TYPES=1+16+32 # 2^type for the types linked to nearest primaries
#FOF_SECONDARY_LINK_TARGET_TYPES= # should normally be set to a list of all dark matter types (in zoom runs), if not set defaults to FOF_PRIMARY_LINK_TYPES
#FOF_GROUP_MIN_LEN=32 # Minimum number of particles in one group (default is 32)
#FOF_LINKLENGTH=0.16 # Linkinglength for FoF (default=0.2)
#FOF_FUZZ_SORT_BY_NEAREST_GROUP=0 # sort fuzz particles by nearest group and generate offset table in catalog (=1 writes nearest group number to snapshot)
#FOF_STOREIDS # store IDs in group/subfind catalogue, do not order particles in snapshot files by group order
#--------------------------------------- Subfind
#SUBFIND # enables substructure finder
#SAVE_HSML_IN_SNAPSHOT # stores hsml, density, and velocity dispersion values in the snapshot files
#SUBFIND_CALC_MORE # calculates also the velocity dispersion in the local density estimate (this is automatically enabled by several other options, e.g. SAVE_HSML_IN_SNAPSHOT)
#SUBFIND_EXTENDED_PROPERTIES # adds calculation of further quantities related to angular momentum in different components
#--------------------------------------- Things for special behaviour
#RUNNING_SAFETY_FILE # if file './running' exists, do not start the run
#MULTIPLE_RESTARTS # Keep restart files instead of just two copies
#EXTENDED_GHOST_SEARCH # This extends the ghost search to the full 3x3 domain instead of the principal domain
#DOUBLE_STENCIL # this will ensure that the boundary region of the local mesh is deep enough to have a valid double stencil for all local cells
#TETRA_INDEX_IN_FACE # adds an index to each entry of VF[] and DC[] to one of the tetrahedra that share this edge
#NOSTOP_WHEN_BELOW_MINTIMESTEP # Simulation does not terminate when timestep drops below minimum timestep
#TIMESTEP_OUTPUT_LIMIT # Limit timesteps to write snaps on time for output lists with huge range
#ALLOWEXTRAPARAMS # Tolerate extra parameters that are not used
#FIX_SPH_PARTICLES_AT_IDENTICAL_COORDINATES # this can be used to load SPH ICs that contain identical particle coordinates
#RECOMPUTE_POTENTIAL_IN_SNAPSHOT # needed for postprocess option 18 that can be used to calculate potential values for a snapshot
#ACTIVATE_MINIMUM_OPENING_ANGLE # this does not open tree nodes under the relative opening criterion any more if their opening angle has dropped below a minimum angle
#USE_DIRECT_IO_FOR_RESTARTS # Try to use O_DIRECT for low-level read/write operations of restart files to circumvent the linux kernel page caching
#HUGEPAGES # use huge pages for memory allocation, through hugetlbfs library
#DETAILEDTIMINGS # creates individual timings entries for primary/secondary kernels to diagnose work-load balancing
