Reusable structure.

Runtime analysis settings.

• subfindgroup
  Uses subfind_analysis_settings

Compile-time capabilities mapped to Config.sh.

• boundariesgroup
  • x_modevalue · int32

    X-boundary mode; zero leaves no REFLECTIVE_X compile option.

    Options: 0, 1, 2
  • y_modevalue · int32

    Y-boundary mode; zero leaves no REFLECTIVE_Y compile option.

    Options: 0, 1, 2
  • z_modevalue · int32

    Z-boundary mode; zero leaves no REFLECTIVE_Z compile option.

    Options: 0, 1, 2
• geometrygroup
  • one_dimensionalvalue · bool

    Restrict the Voronoi mesh and hydrodynamics to one dimension.

  • two_dimensionalvalue · bool

    Restrict the Voronoi mesh and hydrodynamics to two dimensions.

  • spherical_one_dimensionalvalue · bool

    Use one-dimensional spherical geometry.

  • static_meshvalue · bool

    Use a static Voronoi mesh.

• physicsgroup
  • coolingvalue · bool

    Compile radiative cooling and UV-background support.

  • star_formationvalue · bool

    Compile the Springel-Hernquist multiphase star-formation model.

  • jeans_cell_stabilityvalue · bool

    Enforce the Jeans-stability temperature floor for gas cells.

  • magnetohydrodynamicsvalue · bool

    Compile ideal magnetohydrodynamics.

    • powell_cleaningvalue · bool

      Use Powell eight-wave divergence-control terms for MHD.

    • powell_limit_timestepvalue · bool

      Limit timesteps for Powell divergence-control stability.

  • adiabatic_indexvalue · float64

    Compile-time gas adiabatic index; zero selects Arepo's default.

• gravitygroup
  • self_gravityvalue · bool

    Compile gravitational interactions between particles and cells.

  • hierarchicalvalue · bool

    Use hierarchical gravity time integration.

  • cell_center_evaluationvalue · bool

    Evaluate cell gravity at geometric centres; requires hierarchical gravity.

  • direct_summationvalue · bool

    Allow direct summation for small active particle sets.

    • thresholdvalue · int32

      Active-particle threshold below which direct gravity summation is used.

      Condition: {.} > 0
  • multiple_node_softeningvalue · bool

    Retain component-specific softenings when using softened tree nodes.

  • individual_softening_type_maskvalue · int32

    Particle-type bit mask selecting individual gravity softening.

    Condition: {.} >= 0
  • particle_meshvalue · bool

    Enable periodic particle-mesh gravity in the TreePM solver.

    • grid_resolutionvalue · int32

      Particle-mesh cells per dimension; zero is disabled.

      Condition: {.} >= 0
    • short_range_cutoffvalue · float64

      TreePM short-range cutoff in particle-mesh cell units.

      Condition: {.} > 0
    • high_resolution_type_maskvalue · int32

      Particle-type mask defining the TreePM high-resolution region.

    • enlarge_high_resolution_regionvalue · float64

      Expansion factor for the TreePM high-resolution region.

    • high_resolution_grid_boostvalue · int32

      Resolution multiplier for a zoom TreePM grid.

    • zoom_optimizedvalue · bool

      Use the TreePM algorithm optimized for cosmological zoom simulations.

  • non_periodicvalue · bool

    Compile non-periodic gravity.

  • evaluate_potentialvalue · bool

    Calculate gravitational potentials.

  • softening_typesvalue · int32

    Number of available gravitational-softening families.

    Condition: {.} >= 2
• timegroup
  • force_equal_timestepsvalue · bool

    Force all particles/cells onto equal timesteps.

  • tree_based_timestepsvalue · bool

    Use the non-local, tree-based timestep criterion.

• precisiongroup
  • modevalue · int32

    Arepo precision mode; zero leaves DOUBLEPRECISION unspecified.

    Options: 0, 1, 2, 3
  • fftw_doublevalue · bool

    Use double-precision FFTW transforms.

  • neighbor_tree_doublevalue · bool

    Use double precision for neighbor-tree node extensions.

• iogroup
  • hdf5value · bool

    Compile HDF5 snapshot and initial-condition support.

  • reduced_flushvalue · bool

    Reduce log-file flush frequency.

  • input_double_precisionvalue · bool

    Read initial conditions in double precision.

  • output_coordinates_doublevalue · bool

    Always write coordinates in double precision.

  • output_double_precisionvalue · bool

    Write snapshot fields in double precision.

  • read_mass_as_densityvalue · bool

    Interpret IC Mass fields as densities.

  • cpu_csvvalue · bool

    Write the supplementary cpu.csv performance log.

• initial_conditionsgroup
  • generate_gas_from_dark_mattervalue · bool

    Generate gas particles from dark-matter-only initial conditions.

• meshgroup
  • refinementvalue · bool

    Compile cell refinement and derefinement.

  • adaptive_hydro_softeningvalue · bool

    Compile adaptive gas-cell gravitational softening.

  • face_angle_regularizationvalue · bool

    Regularize mesh cells using their maximum face angle.

  • center_of_mass_driftvalue · bool

    Regularize mesh-generating-point drift from cell centres of mass.

  • drift_limited_by_sound_speedvalue · bool

    Limit centre-of-mass regularization by local sound speed.

  • volume_refinementvalue · bool

    Compile volume-limited mesh refinement.

  • no_refine_background_gridvalue · bool

    Exclude the background grid from refinement.

  • override_peanogrid_warningvalue · bool

    Allow configurations that exceed the Peano-grid warning threshold.

• numericsgroup
  • riemann_hlldvalue · bool

    Use the HLLD Riemann solver for ideal MHD.

• analysisgroup
  • fofvalue · bool

    Compile the friends-of-friends halo finder.

    • primary_link_type_maskvalue · int32

      Particle-type bit mask used as FoF primary linking tracers.

      Condition: {.} >= 0
    • secondary_link_type_maskvalue · int32

      Particle-type bit mask attached to nearest FoF primary tracers.

      Condition: {.} >= 0
  • subfindvalue · bool

    Compile the Subfind substructure finder; requires FoF.

    • save_density_estimatesvalue · bool

      Save Subfind smoothing lengths, densities, and velocity dispersions.

    • calculate_velocity_dispersionvalue · bool

      Calculate additional Subfind velocity-dispersion information.

    • extended_propertiesvalue · bool

      Calculate extended Subfind angular-momentum and energy properties.

• outputgroup
  • process_schedule_exactlyvalue · bool

    Process output-list times before starting to improve timing accuracy.

  • center_of_massvalue · bool

    Write gas-cell centres of mass.

  • magnetic_field_gradientvalue · bool

    Write magnetic-field gradients.

  • accelerationvalue · bool

    Write gravitational accelerations.

  • pressure_gradientvalue · bool

    Write pressure gradients.

  • potentialvalue · bool

    Write gravitational potentials.

• diagnosticsgroup
  • debugvalue · bool

    Enable Arepo debugging facilities and core-dump support.

Radiative cooling input.

• uv_background_filevalue · str

  Cooling and UV-background table used by Arepo.

Cosmological background parameters.

• matter_densityvalue · float64

  Present-day total matter density parameter, Omega0.

• baryon_densityvalue · float64

  Present-day baryon density parameter, OmegaBaryon.

• hubble_parametervalue · float64

  Dimensionless Hubble parameter h, written to HubbleParam.

• initial_redshiftvalue · float64

  Initial redshift from which the scale-factor start time is derived.

• final_redshiftvalue · float64

  Final redshift from which the scale-factor end time is derived.

• dark_energy_densityvalue · float64

  Present-day dark-energy density parameter, OmegaLambda.

• dark_matter_densityvalue · float64

  Present-day non-baryonic matter density derived from total and baryon density.

Continuation-job submission settings.

• resubmitvalue · bool

  Whether Arepo should submit a continuation job after reaching its time limit.

• resubmit_commandvalue · str

  Command used to submit the continuation job when resubmission is enabled.

Local experiment identity settings.

• setupgroup
  Uses experiment_setup_selection

Local selection of bundled AREPO examples.

• kindvalue · str

  Selects the scientific setup branch represented by this DIPL environment.

  Options: cosmological_star_formation, cosmological_gravity_only, mhd_shock_tube, alfven_wave_1d, cosmo_zoom_gravity_only_3d, current_sheet_2d, galaxy_merger_star_formation_3d, gresho_2d, interacting_blastwaves_1d, isolated_galaxy_collisionless_3d, noh_2d, noh_3d, polytrope_1d_spherical, shocktube_1d, wave_1d, yee_2d

Domain decomposition controls.

• multiple_domainsvalue · int32

  Number of simultaneous domain decompositions.

  Condition: {.} >= 1
• top_node_factorvalue · float64

  Top-level tree-node allocation factor.

  Condition: {.} > 0
• active_fractionvalue · float64

  Active-particle fraction that triggers a domain decomposition.

  Condition: {.} >= 0

Gravity accuracy controls.

• integrationvalue · float64

  Integration accuracy tolerance.

• opening_anglevalue · float64

  Tree opening angle.

• relative_forcevalue · float64

  Relative force-error tolerance.

• opening_criterionvalue · int32

  Tree opening-criterion selector.

  Options: 0, 1

Adaptive gas softening settings.

• gas_softening_factorvalue · float64

  Gas-cell softening relative to the assigned base softening.

  Condition: {.} > 0
• minimum_comovingvalue · float64 · arepo_length

  Minimum comoving adaptive gas softening.

• spacingvalue · float64

  Geometric spacing between adaptive gas softening levels.

  Condition: {.} >= 1

Gravity and softening settings.

• constant_internalvalue · float64

  Gravitational constant in the selected internal code-unit system.

• force_accuracygroup
  Uses gravity_force_accuracy
• domain_decompositiongroup
  Uses gravity_domain_decomposition
• hydrogroup
  Uses gravity_hydro_softening

One gravitational softening length.

• lengthvalue · float64 · arepo_length

  Gravity softening length in Arepo code-length units; the schema default is overridden by each setup.

  Condition: {.} > 0 arepo_length

Gas evolution controls.

• courant_factorvalue · float64

  Courant-Friedrichs-Lewy timestep factor.

  Condition: {.} >= 0
• initial_gas_temperaturevalue · float64 · K

  Initial gas temperature used where initial conditions lack it.

• minimum_gas_temperaturevalue · float64 · K

  Temperature floor applied to gas.

• minimum_startup_densityvalue · float64 · arepo_density

  Minimum density imposed while starting the run.

• internal_energy_density_limitvalue · float64 · arepo_density

  Density threshold for an internal-energy limit.

• internal_energy_floorvalue · float64 · arepo_specific_energy

  Internal-energy floor applied below the configured density threshold.

• minimum_specific_energyvalue · float64 · arepo_specific_energy

  Minimum specific internal energy.

• target_neighborsvalue · int32

  Desired hydrodynamic neighbor count.

  Condition: {.} > 0
• maximum_neighbor_deviationvalue · int32

  Permitted deviation from the desired neighbor count.

  Condition: {.} >= 0

Initial-condition paths and formats.

• pathvalue · str

  Initial-condition file path, without an automatically appended format suffix.

• formatvalue · int32

  Serialization format used to read the initial conditions.

  Options: 1, 2, 3

Simulation input settings.

• initial_conditionsgroup
  Uses initial_conditions_settings

Per-rank memory allocation.

• per_rankvalue · int32

  Memory allocated to each MPI rank, in MiB.

  Condition: {.} > 0

Refinement and derefinement controls.

• reference_gas_massvalue · float64 · arepo_mass

  Reference gas-cell mass for refinement.

• target_gas_mass_factorvalue · float64

  Target gas-mass multiplier for refinement.

  Condition: {.} > 0
• refinement_criterionvalue · int32

  Arepo refinement-criterion selector.

• derefinement_criterionvalue · int32

  Arepo derefinement-criterion selector.

Mesh regularization controls.

• shaping_speedvalue · float64

  Speed of mesh regularization.

  Condition: {.} >= 0
• maximum_face_angle_factorvalue · float64

  Maximum-face-angle roundness threshold.

  Condition: {.} > 0
• shaping_factorvalue · float64

  Centre-of-mass mesh-roundness threshold; zero disables this criterion.

  Condition: {.} >= 0

Mesh adaptation settings.

• regularizationgroup
  Uses mesh_regularization
• refinementgroup
  Uses mesh_refinement

Explicit snapshot scheduling.

• enabledvalue · bool

  Whether Arepo reads an explicit output-time schedule file.

• filenamevalue · str

  Path to the output-time schedule file when scheduling is enabled.

Snapshot and scheduling settings.

• schedulegroup
  Uses output_schedule_settings
• snapshotsgroup
  Uses snapshot_settings

Memory and execution resources.

• memorygroup
  Uses memory_resources
• wall_clockgroup
  Uses wall_clock_resources
• executiongroup
  Uses execution_resources

Computational box size.

• sizevalue · float64 · arepo_length

  Simulation-box edge length in the selected Arepo code-length unit.

  Condition: {.} > 0 arepo_length

Domain extent and boundaries.

• boundaryvalue · str

  Whether the simulation domain has periodic boundaries.

  Options: periodic, non_periodic
• boxgroup
  Uses simulation_box

Spatial and temporal settings.

• domaingroup
  Uses simulation_domain
• timegroup
  Uses simulation_time

Integration interval and output cadence.

• coordinatevalue · str

  Independent coordinate used by the time integrator.

  Options: scale_factor, linear
• initial_redshiftvalue · float64

  Redshift represented by the initial conditions.

• final_redshiftvalue · float64

  Redshift at which a cosmological integration ends.

• beginvalue · float64

  Initial integration coordinate; often derived from the initial redshift.

• endvalue · float64

  Final integration coordinate.

  Condition: {.} >= {?simulation.time.begin}
• maximum_stepvalue · float64

  Maximum permitted integration step.

  Condition: {.} > 0
• minimum_stepvalue · float64

  Minimum permitted integration step; zero delegates the lower limit to Arepo.

  Condition: {.} >= 0
• statistics_intervalvalue · float64

  Interval between time-statistics reports.

  Condition: {.} >= 0
• first_snapshotvalue · float64

  First regularly spaced snapshot time when no output schedule is used.

• snapshot_intervalvalue · float64

  Spacing of regular snapshots when no output schedule is used.

  Condition: {.} >= 0
• timestep_criterionvalue · int32

  Global time-step criterion used by Arepo.

  Options: 0, 1

Snapshot naming and storage.

• directoryvalue · str

  Directory receiving Arepo snapshots.

• base_namevalue · str

  Prefix used for snapshot filenames.

• formatvalue · int32

  Arepo snapshot serialization format.

  Options: 1, 2, 3
• filesvalue · int32

  Number of files produced for each snapshot.

  Condition: {.} >= 1
• parallel_filesvalue · int32

  Maximum number of snapshot files written concurrently.

  Condition: {.} >= 1

Star-formation model parameters.

• critical_overdensityvalue · float64

  Critical overdensity above which star formation may occur in a comoving integration.

• temperature_thresholdvalue · float64 · K

  Maximum gas temperature eligible for star formation.

• critical_physical_densityvalue · float64 · kg/m3

  Critical physical density above which star formation may occur in a non-comoving integration.

• supernova_temperaturevalue · float64 · K

  Hot inter-cloud-medium temperature in the Springel-Hernquist model.

• cloud_temperaturevalue · float64 · K

  Cold-cloud temperature in the Springel-Hernquist model.

• maximum_timescalevalue · float64 · arepo_time

  Star-formation timescale at the density threshold.

• supernova_factorvalue · float64

  Mass fraction of massive stars formed for an initial stellar population.

• evaporation_factorvalue · float64

  Cloud-evaporation efficiency in the Springel-Hernquist model.

Subfind runtime controls.

• linking_neighborsvalue · int32

  Minimum number of particles/cells retained in a Subfind group.

  Condition: {.} > 0
• opening_anglevalue · float64

  Subfind tree opening angle.

  Condition: {.} > 0

Runtime limits and restart intervals.

• limitvalue · float64 · s

  Wall-clock limit before Arepo stops cleanly for restart.

  Condition: {.} > 0 s
• restart_intervalvalue · float64 · s

  Interval between restart-file writes.

  Condition: {.} >= 0 s
• log_flush_intervalvalue · float64 · s

  Interval between explicit log-file flushes; zero leaves this disabled.

  Condition: {.} >= 0 s