vice.milkyway.mass_loading
==========================

Type : ``<function>``

Default : vice.milkyway.default_mass_loading

The mass-loading factor as a function of galactocentric radius in kpc
describing the efficiency of outflows. For a given star formation rate
:math:`\dot{M}_\star` and an outflow rate :math:`\dot{M}_\text{out}`,
the mass-loading factor is defined as the unitless ratio:

.. math:: \eta \equiv \dot{M}_\text{out} / \dot{M}_\star

This function must return a non-negative real number for all radii
defined in the disk model.

.. note:: This formalism assumes a time-independent mass-loading
	factor at each radius. To implement a time-dependent alternative,
	users should modify the attribute ``eta`` of the ``singlezone``
	objects corresponding to each annulus in this model. See example
	below.

.. seealso:: vice.singlezone.eta

Example Code
------------
>>> import math as m
>>> import vice
>>> mw = vice.milkyway(name = "example")
>>> def f(r):
	return 0.5 * m.exp(r / 3)
>>> mw.mass_loading = f
>>> def g(t): # a time-dependent mass-loading factor
	return 3.0 * m.exp(-t / 3)
>>> # assign each individual annulus a time-dependent value
>>> for i in range(mw.n_zones):
>>> 	mw.zones[i].eta = g