Coverage for python/lsst/afw/table/_source.py: 34%
Shortcuts on this page
r m x p toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
Shortcuts on this page
r m x p toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
1# This file is part of afw.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (https://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <https://www.gnu.org/licenses/>.
22__all__ = []
24from lsst.utils import continueClass
25from ._base import Catalog
26from ._table import SourceCatalog, SourceTable
28Catalog.register("Source", SourceCatalog)
31@continueClass
32class SourceCatalog:
34 def getChildren(self, parent, *args):
35 """Return the subset of self for which the parent field equals the
36 given value.
38 In order for this method to return the correct result, it must be
39 sorted by parent (i.e. self.isSorted(SourceTable.getParentKey()) must
40 be True). This is naturally the case with SourceCatalogs produced by
41 the detection and deblending tasks, but it may not be true when
42 concatenating multiple such catalogs.
44 Additional Catalogs or sequences whose elements correspond in order to
45 the records of self (i.e. ``zip(self, *args)`` is valid) will be
46 subset using the same slice object used on self, and these subsets
47 will be returned along with the subset of self.
49 Parameters
50 ----------
51 parent : `int` or `iterable` of `int`
52 ID(s) of the parent(s) to get children for.
53 args : `~lsst.afw.table.Catalog`
54 Additional catalogs to subset for the children to return.
56 Returns
57 -------
58 children : a single iterable of `~lsst.afw.table.SourceRecord`
59 Children sources if ``parent`` is of type `int`, or a generator
60 yielding a `~lsst.afw.table.SourceRecord`s Children sources for
61 each parent if ``parent`` is an `iterable`.
63 Raises
64 ------
65 AssertionError
66 Raised if the catalog is not sorted by the parent key.
68 Notes
69 -----
70 Each call to this function checks if the catalog is sorted, which is
71 of O(n) complexity, while fetching the children is of O(log n). To
72 minimize the computational overhead, it is preferable to prepare an
73 iterable of parent ids for which the children need to be fetched and
74 pass the iterable as ``parent``.
75 """
76 if not self.isSorted(SourceTable.getParentKey()):
77 raise AssertionError(
78 "The table is not sorted by parent, so cannot getChildren")
80 def _getChildrenWithoutChecking(parent):
81 """Return the subset of self for which the parent field equals the
82 given value.
84 This function works as desired only if `self` is sorted by the
85 parent key, but does not check if it is sorted. This function must
86 be used only after ensuring outside of the function that
87 self.isSorted(SourceTable.getParentKey() evaluates to True.
89 Parameter
90 ---------
91 parent : `int`
92 ID of the parent to get children for.
94 Returns
95 -------
96 children : iterable of `~lsst.afw.table.SourceRecord`
97 Children sources.
98 """
99 s = self.equal_range(parent, SourceTable.getParentKey())
100 if args:
101 return (self[s],) + tuple(arg[s] for arg in args)
102 else:
103 return self[s]
105 try:
106 return (_getChildrenWithoutChecking(p) for p in parent)
107 except TypeError:
108 return _getChildrenWithoutChecking(parent)