vice.singlezone.recycling
=========================

Type : real number or ``str`` [case-insensitive]

Default : "continuous"

The :ref:`cumulative return fraction <crf>` :math:`r(t)`. This is the
mass fraction of a single stellar population returned to the
interstellar medium as gas at the birth metallicity of the stars.

The only allowed string is "continuous" [case-insensitive]. In this
case VICE will implement time-dependent recycling from each episode
of star formation via a treatment of the stellar initial mass
function and the initial-final remnant mass model of Kalirai at al.
(2008) [1]_.

Numbers must be between 0 and 1 (inclusive), and will be interpreted
as the instantaneous recycling fraction: the fraction of a stellar
population's mass that is returned to the interstellar medium
immediately following its formation.

.. note::

	In the case of instantaneous recycling, it is recommened that users
	adopt r = 0.4 with the Kroupa [2]_ IMF and r = 0.2 with the
	Salpeter [3]_ IMF based on the findings of Weinberg, Andrews &
	Freudenburg (2017) [4]_.

Example Code
------------
>>> import vice
>>> sz = vice.singlezone(name = "example", IMF = "kroupa")
>>> sz.recycling = 0.4
>>> sz.IMF = "salpeter"
>>> sz.recycling = 0.2
>>> sz.recycling = "continuous"

.. [1] Kalirai et al. (2008), ApJ, 676, 594
.. [2] Kroupa (2001), MNRAS, 231, 322
.. [3] Salpeter (1955), ApJ, 131, 161
.. [4] Weinberg, Andrews & Freudenburg (2017), ApJ, 837, 183