"""
AncestryChecker functions
"""
#-----------------------------------------------------------------------------
# Copyright (c) ytree development team. All rights reserved.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file COPYING.txt, distributed with this software.
#-----------------------------------------------------------------------------
import numpy as np
from yt.utilities.operator_registry import \
OperatorRegistry
ancestry_checker_registry = OperatorRegistry()
[docs]def add_ancestry_checker(name, function):
"""
Add an ancestry checking function to the registry.
"""
ancestry_checker_registry[name] = AncestryChecker(function)
[docs]class AncestryChecker(object):
r"""
An AncestryCheck is a function that is responsible for determining
whether one halo is an ancestor of another.
Parameters
----------
descendent_ids : list of ints
Member ids for first halo.
ancestor_ids : list of int
Member ids for second halo.
The function should return True or False.
"""
[docs] def __init__(self, function, args=None, kwargs=None):
self.function = function
self.args = args
if self.args is None: self.args = []
self.kwargs = kwargs
if self.kwargs is None: self.kwargs = {}
def __call__(self, descendent_ids, ancestor_ids):
return self.function(descendent_ids, ancestor_ids,
*self.args, **self.kwargs)
[docs]def common_ids(descendent_ids, ancestor_ids, threshold=0.5):
r"""
Determine if at least a given fraction of ancestor's member particles
are in the descendent.
Parameters
----------
descendent_ids : list of ints
Member ids for first halo.
ancestor_ids : list of int
Member ids for second halo.
threshold : float, optional
Critical fraction of ancestor's particles ending up in the
descendent to be considered a true ancestor. Default: 0.5.
Returns
-------
True or False
"""
common = np.intersect1d(descendent_ids, ancestor_ids)
return common.size > threshold * ancestor_ids.size
add_ancestry_checker("common_ids", common_ids)