def test_matching_method():
from astropy.coordinates import ICRS, SkyCoord
from astropy.utils import NumpyRNGContext
from astropy.coordinates.matching import match_coordinates_3d, match_coordinates_sky
with NumpyRNGContext(987654321):
cmatch = ICRS(
np.random.rand(20) * 360. * u.degree,
(np.random.rand(20) * 180. - 90.) * u.degree)
ccatalog = ICRS(
np.random.rand(100) * 360. * u.degree,
(np.random.rand(100) * 180. - 90.) * u.degree)
idx1, d2d1, d3d1 = SkyCoord(cmatch).match_to_catalog_3d(ccatalog)
idx2, d2d2, d3d2 = match_coordinates_3d(cmatch, ccatalog)
npt.assert_array_equal(idx1, idx2)
assert_allclose(d2d1, d2d2)
assert_allclose(d3d1, d3d2)
# should be the same as above because there's no distance, but just make sure this method works
idx1, d2d1, d3d1 = SkyCoord(cmatch).match_to_catalog_sky(ccatalog)
idx2, d2d2, d3d2 = match_coordinates_sky(cmatch, ccatalog)
npt.assert_array_equal(idx1, idx2)
assert_allclose(d2d1, d2d2)
assert_allclose(d3d1, d3d2)
assert len(idx1) == len(d2d1) == len(d3d1) == 20
def test_matching_function():
from astropy.coordinates import ICRS
from astropy.coordinates.matching import match_coordinates_3d
# this only uses match_coordinates_3d because that's the actual implementation
cmatch = ICRS([4, 2.1] * u.degree, [0, 0] * u.degree)
ccatalog = ICRS([1, 2, 3, 4] * u.degree, [0, 0, 0, 0] * u.degree)
idx, d2d, d3d = match_coordinates_3d(cmatch, ccatalog)
npt.assert_array_equal(idx, [3, 1])
npt.assert_array_almost_equal(d2d.degree, [0, 0.1])
assert d3d.value[0] == 0
idx, d2d, d3d = match_coordinates_3d(cmatch, ccatalog, nthneighbor=2)
assert np.all(idx == 2)
npt.assert_array_almost_equal(d2d.degree, [1, 0.9])
npt.assert_array_less(d3d.value, 0.02)
def test_matching_function_3d_and_sky():
from astropy.coordinates import ICRS
from astropy.coordinates.matching import match_coordinates_3d, match_coordinates_sky
cmatch = ICRS([4, 2.1]*u.degree, [0, 0]*u.degree, distance=[1, 5] * u.kpc)
ccatalog = ICRS([1, 2, 3, 4]*u.degree, [0, 0, 0, 0]*u.degree, distance=[1, 1, 1, 5] * u.kpc)
idx, d2d, d3d = match_coordinates_3d(cmatch, ccatalog)
npt.assert_array_equal(idx, [2, 3])
assert_allclose(d2d, [1, 1.9] * u.deg)
assert np.abs(d3d[0].to_value(u.kpc) - np.radians(1)) < 1e-6
assert np.abs(d3d[1].to_value(u.kpc) - 5*np.radians(1.9)) < 1e-5
idx, d2d, d3d = match_coordinates_sky(cmatch, ccatalog)
npt.assert_array_equal(idx, [3, 1])
assert_allclose(d2d, [0, 0.1] * u.deg)
assert_allclose(d3d, [4, 4.0000019] * u.kpc)
