vice.singlezone.func
====================

Type : ``<function>``

Default : vice._globals._DEFAULT_FUNC_

A callable object which must accept time in Gyr as the only parameter.
The value returned by this function will represent either the gas
infall history in :math:`M_\odot\ yr^{-1}` (``mode`` == "ifr"), the
star formation history in :math:`M_\odot\ yr^{-1}` (``mode`` == "sfr"),
or the ISM gas supply in :math:`M_\odot` (``mode`` == "gas).

.. note::

	The default function returns the value of 9.1 always. With a
	default ``mode`` of "ifr", this corresponds to an infall rate of
	9.1 :math:`M_\odot\ yr^{-1}` at all times.

.. note::

	Saving this functional attribute with VICE outputs requires the
	package dill_, an extension to ``pickle`` in the Python_ standard
	library. It is recommended that VICE user's install dill_
	>= 0.2.0.

	.. _dill: https://pypi.org/project/dill/
	.. _Python: https://docs.python.org/library/

.. note::

	This attribute  will always be expected to accept time
	in Gyr as the only parameter. However, infall and star formation
	rates will be interpreted as having units of
	:math:`M_\odot\ yr^{-1}` according to convention.

.. seealso:: vice.singlezone.mode

Example Code
------------
>>> import math as m
>>> import vice
>>> sz = vice.singlezone(name = "example")
>>> def f(t):
	if t <= 1:
		return 10
	else:
		return 10 * m.exp(-(t - 1) / 3)
>>> sz.func = f
>>> sz.func = lambda t: 10. * m.exp(-t / 3)