_match.py

Go to the documentation of this file.

# This file is part of afw.
#
# Developed for the LSST Data Management System.
# This product includes software developed by the LSST Project
# (https://www.lsst.org).
# See the COPYRIGHT file at the top-level directory of this distribution
# for details of code ownership.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
__all__ = ["SimpleMatch", "ReferenceMatch", "SourceMatch", "clone", "matchCls", "packMatches"]
 
import numpy as np
 
from ._base import BaseCatalog
from ._schema import Schema
from ._table import SimpleMatch, ReferenceMatch, SourceMatch
 
 
def __repr__(self):  # noqa: N807
    return "Match(%s,\n            %s,\n            %g)" % \
        (repr(self.first), repr(self.second), self.distance)
 
 
def __str__(self):  # noqa: N807
    def sourceRaDec(s):
        if hasattr(s, "getRa") and hasattr(s, "getDec"):
            return " RA,Dec=(%g,%g) deg" % (s.getRa().asDegrees(), s.getDec().asDegrees())
        return ""
 
    def sourceXy(s):
        if hasattr(s, "getX") and hasattr(s, "getY"):
            return " x,y=(%g,%g)" % (s.getX(), s.getY())
        return ""
 
    def sourceStr(s):
        return s.__class__.__name__ + ("(id %d" % s.getId()) + sourceRaDec(s) + sourceXy(s) + ")"
 
    return "Match(%s, %s, dist %g)" % (sourceStr(self.first), sourceStr(self.second), self.distance,)
 
 
def __getitem__(self, i):  # noqa: N807
    """Treat a Match as a tuple of length 3: (first, second, distance)"""
    if i > 2 or i < -3:
        raise IndexError(i)
    if i < 0:
        i += 3
    if i == 0:
        return self.first
    elif i == 1:
        return self.second
    else:
        return self.distance
 
 
def __setitem__(self, i, val):  # noqa: N807
    """Treat a Match as a tuple of length 3: (first, second, distance)"""
    if i > 2 or i < -3:
        raise IndexError(i)
    if i < 0:
        i += 3
    if i == 0:
        self.first = val
    elif i == 1:
        self.second = val
    else:
        self.distance = val
 
 
def __len__(self):  # noqa: N807
    return 3
 
 
def clone(self):
    return self.__class__(self.first, self.second, self.distance)
 
 
# Pickling support disabled for this type (see testSourceMatch comment for reasoning)
# def __getstate__(self):
#    return self.first, self.second, self.distance
#
#
# def __setstate__(self, state):
#    self.__init__(*state)
 
 
for matchCls in (SimpleMatch, ReferenceMatch, SourceMatch):
    matchCls.__repr__ = __repr__
    matchCls.__str__ = __str__
    matchCls.__getitem__ = __getitem__
    matchCls.__setitem__ = __setitem__
    matchCls.__len__ = __len__
    matchCls.clone = clone
#    matchCls.__getstate__ = __getstate__
#    matchCls.__setstate__ = __setstate__
 
 
def packMatches(matches):
    """Make a catalog of matches from a sequence of matches.
 
    The catalog contains three fields:
    - first: the ID of the first source record in each match
    - second: the ID of the second source record in each match
    - distance: the distance of each match
 
    Parameters
    ----------
    matches :
        Sequence of matches, typically of type SimpleMatch,
        ReferenceMatch or SourceMatch.  Each element must support:
        `.first.getId()`->int, `.second.getId()->int` and
        `.distance->float`.
 
    Returns
    -------
    result :
        The catalog of matches.
 
    Notes
    -----
    This pure python implementation exists as a historical artifact
    related to SWIG limitations. It might be practical to wrap the
    overloaded C++ functions with pybind11, but there didn't seem much
    point.
    """
    schema = Schema()
    outKey1 = schema.addField("first", type=np.int64,
                              doc="ID for first source record in match.")
    outKey2 = schema.addField("second", type=np.int64,
                              doc="ID for second source record in match.")
    keyD = schema.addField("distance", type=np.float64,
                           doc="Distance between matches sources.")
    result = BaseCatalog(schema)
    result.table.preallocate(len(matches))
    for match in matches:
        record = result.addNew()
        record.set(outKey1, match.first.getId())
        record.set(outKey2, match.second.getId())
        record.set(keyD, match.distance)
    return result