Configuration

ViSAGE reads all simulation parameters directly from the SAGE .par file. No separate config file is needed.

CLI options

Option	Default	Description
--par FILE	(required unless --lightcone)	Path to SAGE .par file. Omit both --par and --lightcone to start in Launch Mode
--lightcone FILE	—	Path to a cli_lightcone HDF5 output file — opens the full Explore UI on the lightcone instead of a SAGE box
--snap N	last snap	Initial snapshot number
--port N	8080	Trame server port
--n-jobs N	CPUs-1	Parallel workers for halo loading
--min-halo-mass MSUN	1e10	Minimum halo mass floor (Msun)
--min-stellar-mass MSUN	1e8	Minimum stellar mass floor (Msun)
--max-halos N	100000	Downsample ceiling for haloes per snapshot

Galaxies have no display cap — every galaxy passing the mass floor is loaded (all snapshots are preloaded, so there's no need to downsample for playback speed).

Par file fields used

ViSAGE reads the following fields from the .par file:

Field	Used for
OutputDir	Locating SAGE HDF5 galaxy output
FileNameGalaxies	Galaxy output file base name
FirstFile / LastFile	Range of tree files to read
SimulationDir	Directory containing the merger tree files (lhalo_binary or lhalo_hdf5)
TreeName	Base name of tree files (e.g. trees_063)
FileWithSnapList	Scale factor list file
LastSnapShotNr	Number of snapshots
Hubble_h	Unit conversion
BoxSize	Camera framing and zoom-to-box

Performance tuning

For interactive use on a laptop with miniMillennium:

visage --par input/millennium.par \
  --max-halos 30000 \
  --min-halo-mass 1e11 \
  --n-jobs 4

For cluster use with full data:

visage --par input/millennium.par \
  --max-halos 100000 \
  --n-jobs 16 \
  --port 8080