vice.singlezone.Zin
===================

Type : real number, ``<function>``, or ``dataframe``

Default : 0.0

The metallicity of gas inflow. Numbers and functions apply to all
elements tracked by the simulation. Functions must accept time in Gyr
as the only parameter. A dictionary or a ``dataframe`` can also be
passed, allowing real numbers and functions to be assigned on an
element-by-element basis.

This attribute quantifies only the metallicity of gas inflow *in excess*
of that which is produced by the big bang. For example, even when this
attribute is set to 0 for helium, its abundance by mass in accreting
gas will still be given by ``vice.primordial["he"]``. If the element in
question was not produced during big bang nucleosynthesis (i.e.
``vice.primordial["x"] = 0`` for some element "x"), then the same
numerical solution applies and this attribute quantifies the total
abundance by mass in the inflow.

.. versionadded:: 1.3.1

	In previous versions, the primordial abundance by mass of each
	element was included in the numerical calculation of the inflow
	metallicity but was not recorded in the output. That is, an inflow
	metallicity of zero for helium meant that its abundance in
	infalling gas was exactly the primordial abundance. With this
	patch, this book-keeping is adjusted to account for this, and
	outputs will reflect a non-zero abundance in primordial gas.

.. tip::

	The easiest way to switch this attribute to a dataframe is by
	passing an empty python dictionary ``{}``.

.. note::

	Dictionaries will be automatically converted into a ``dataframe``.

.. note::

	Saving functional attributes 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/

Example Code
------------
>>> import vice
>>> sz = vice.singlezone(name = "example")
>>> sz.Zin = 0.001
>>> def f(t):
	return 0.001 * (t / 5)
>>> sz.Zin = lambda t: 0.001 * (t / 5)
>>> sz.Zin = {}
>>> sz.Zin
vice.dataframe{
	sr -------------> 0.0
	fe -------------> 0.0
	o --------------> 0.0
}
>>> sz.Zin["o"] = 0.001
>>> sz.Zin["fe"] = lambda t: 1.0e-04 * (t / 5)
>>> sz.Zin
vice.dataframe{
	sr -------------> 0.0
	fe -------------> <function main.<__lambda__>(t)>
	o --------------> 0.001
}