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
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=500 # Overrides maximum number of active particles for which direct summation is performed instead of tree based calculation
PMGRID=256 # Enables particle mesh; number of cells used for grid in each dimension
RCUT=5.0 # 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.
#--------------------------------------- Time integration options
TREE_BASED_TIMESTEPS # non-local timestep criterion (take 'signal speed' into account)
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_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
#--------------------------------------- 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
PROCESS_TIMES_OF_OUTPUTLIST # goes through times of output list prior to starting the simulaiton to ensure that outputs are written as close to the desired time as possible (as opposed to at next possible time if this flag is not active)