pynbody.halo.DummyHalo

class pynbody.halo.DummyHalo

Bases: ContainerWithPhysicalUnitsOption

Methods

physical_units(*args, **kwargs)

Converts all arrays' units to be consistent with the distance, velocity, mass basis units specified.

__init__()

physical_units(*args, **kwargs)

Converts all arrays’ units to be consistent with the distance, velocity, mass basis units specified.

Parameters:

• distance (string (default = 'kpc')) – The distance unit to convert to.

• velocity (string (default = 'km s^-1')) – The velocity unit to convert to.

• mass (string (default = 'Msol')) – The mass unit to convert to.

• persistent (boolean (default = True)) – Apply units change to future lazy-loaded arrays if True.

• convert_parent (boolean (default = True)) – Propagate units change from a halo catalogue to a parent snapshot. See note below.

Note

The option convert_parent is only applicable to Halo objects. It is ignored by all other objects, including pynbody.snapshot.simsnap.SimSnap, pynbody.snapshot.subsnap.SubSnap, and pynbody.halo.HaloCatalogue objects.

When physical_units is called on a pynbody.halo.Halo and convert_parent is True, no immediate action is taken on the pynbody.halo.Halo itself; rather the request is passed upwards to the pynbody.halo.HaloCatalogue.

The catalogue object then calls physical_units on the parent snapshot and on all cached halos, setting convert_parent=False so that the units change is then applied to the pynbody.halo.Halo object itself.

This ensures that unit changes propagate through to properties of all halos. Most users will not need to worry about this subtlety; things should ‘just work’ if you ignore the convert_parent option.