vice.migration.specs
====================

Multizone simulation migration prescriptions for gas and stars.

**Signature**: vice.migration.specs(n)

.. versionadded:: 1.2.0

Parameters
----------
n : ``int``
	The number of rows and columns in the gas migration matrix. This is
	also the number of zones in a multizone model.

Attributes
----------
gas : ``mig_matrix``
	A matrix containing the mass fraction of gas moving between zones.
stars : <function>
	A function of the zone number and time of star formation. Expected to
	return a function of time in Gyr describing the zone number at all
	subsequent times of stars forming in that zone at that time.

Example Code
------------
>>> import math
>>> import vice
>>> example = vice.migration.specs(3)
>>> def f(zone, tform, time):
	# swap stars between zones 0 and 1 when they're >1 Gyr old.
	if zone == 0:
		if time - tform > 1:
			return 1
		else:
			return 0
	elif zone == 1:
		if time - tform > 1:
			return 0
		else:
			return 1
	else:
		return zone
>>> example.stars = f
>>> example.gas[1][0] = 0.1
>>> def g(t):
	return 0.2 * math.exp(-t / 2)
>>> example.gas[0][1] = g
>>> example.gas
	MigrationMatrix{
		0 ---------> {0.0, <function g at 0x120588560>, 0.0}
		1 ---------> {0.1, 0.0, 0.0}
		2 ---------> {0.0, 0.0, 0.0}
	}




.. toctree::
	:titlesonly:
	:maxdepth: 5

	vice.migration.specs.gas
	vice.migration.specs.stars