Output in MUSIC is performed using output plug-ins. The parameters that are given in this section will be parsed by each plugin itself. Therefore the specific parameters available depend on the output plug-in chosen. However, all output-plugins are required to work in a minimal setting, when no options are given besides a filename. Then:

key	description	type
format	the string identifier that selects the plug-in. See below	string
filename	name and path of the file (or directory - depending on the plug-in) where the output data will be stored	string

You can get a list of all compiled in plugins by calling music without any arguments.

The following plugins are currently documented below:

• Generic HDF5 plugin 'generic'
• RAMSES/grafic2 compat. plugin 'grafic2'
• Gadget-2/3 plugin 'gadget2'
• Gadget-2/3 HDF5 plugin 'gadget_hdf5' and 'gadget_hdf5_double'
• Arepo plugin 'arepo' and 'arepo_double'
• SWIFT plugin 'SWIFT'
• HACC plugin 'genericio'

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The generic plugin can be used to output simple HDF5 data arrays for all fields that can be readily used for subsequent analysis or visualization with other tools. The specific options in section [output] are

key	description	type
generic_out_eulerian	Determine whether Eulerian space fields should be written out (in which case PPT is used), or Lagrangian space (in which case LPT is used)	bool

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This is the format for RAMSES. The specific options in section [output] are

key	description	type
grafic_use_SPT	Specify if SPT (only linear!) or PPT (up to 2PPT) shall be used for baryon fields	bool

---

This is the Gadget-2/3 'fortran unformatted binary'-style format. The specific options in section [output] are

key	description	type
UseLongids	Specify whether 32 or 64 bit IDs shall be generated	bool

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This is the HDF5 format for Gadget-2/3. The specific options in section [output] are

key	description	type
UseLongids	Specify whether 32 or 64 bit IDs shall be generated	bool

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This is the format for Arepo. The specific options in section [output] are

key	description	type
UseLongids	Specify whether 32 or 64 bit IDs shall be generated	bool

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This is the SWIFT compatible HDF5 format. Format broadly similar to gadget_hdf5 but in a single file even when using MPI. No h-factors for position and masses and no sqrt(a)-factor for the velocities. IDs are stored using 64-bits unless UseLongids is set to false. The specific options in section [output] are

key	description	type
UseLongids	Specify whether 32 or 64 bit IDs shall be generated. Default: true	bool

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This is the format for HACC. The GenericIO plugin needs to be enabled during compile-time, see compile-time options. The specific options in section [output] are

key	description	type
GenericIO_HACCHydro	Specify if initial conditions for the HACC trunk (false) or HACC-Hydro (true) branch shall be generated. Default: false	bool

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