# -*- coding: utf-8 -*- # Licensed under a 3-clause BSD style license - see LICENSE.rst from __future__ import (absolute_import, division, print_function, unicode_literals) """ This includes tests for the Distance class and related calculations """ import numpy as np from numpy import testing as npt from ...tests.helper import pytest from ... import units as u from .. import Longitude, Latitude, Distance, CartesianRepresentation from ..builtin_frames import ICRS, Galactic try: import scipy # pylint: disable=W0611 except ImportError: HAS_SCIPY = False else: HAS_SCIPY = True def test_distances(): """ Tests functionality for Coordinate class distances and cartesian transformations. """ ''' Distances can also be specified, and allow for a full 3D definition of a coordinate. ''' #try all the different ways to initialize a Distance distance = Distance(12, u.parsec) Distance(40, unit=u.au) Distance(value=5, unit=u.kpc) # need to provide a unit with pytest.raises(u.UnitsError): Distance(12) # standard units are pre-defined npt.assert_allclose(distance.lyr, 39.138765325702551) npt.assert_allclose(distance.km, 370281309776063.0) # Coordinate objects can be assigned a distance object, giving them a full # 3D position c = Galactic(l=158.558650*u.degree, b=-43.350066*u.degree, distance=Distance(12, u.parsec)) #or initialize distances via redshifts - this is actually tested in the #function below that checks for scipy. This is kept here as an example #c.distance = Distance(z=0.2) # uses current cosmology #with whatever your preferred cosmology may be #c.distance = Distance(z=0.2, cosmology=WMAP5) # Coordinate objects can be initialized with a distance using special # syntax c1 = Galactic(l=158.558650*u.deg, b=-43.350066*u.deg, distance=12 * u.kpc) # Coordinate objects can be instantiated with cartesian coordinates # Internally they will immediately be converted to two angles + a distance cart = CartesianRepresentation(x=2 * u.pc, y=4 * u.pc, z=8 * u.pc) c2 = Galactic(cart) sep12 = c1.separation_3d(c2) # returns a *3d* distance between the c1 and c2 coordinates # not that this does *not* assert isinstance(sep12, Distance) npt.assert_allclose(sep12.pc, 12005.784163916317, 10) ''' All spherical coordinate systems with distances can be converted to cartesian coordinates. ''' cartrep2 = c2.cartesian assert isinstance(cartrep2.x, u.Quantity) npt.assert_allclose(cartrep2.x.value, 2) npt.assert_allclose(cartrep2.y.value, 4) npt.assert_allclose(cartrep2.z.value, 8) # with no distance, the unit sphere is assumed when converting to cartesian c3 = Galactic(l=158.558650*u.degree, b=-43.350066*u.degree, distance=None) unitcart = c3.cartesian npt.assert_allclose(((unitcart.x**2 + unitcart.y**2 + unitcart.z**2)**0.5).value, 1.0) # TODO: choose between these when CartesianRepresentation gets a definite # decision on whether or not it gets __add__ # # CartesianRepresentation objects can be added and subtracted, which are # vector/elementwise they can also be given as arguments to a coordinate # system #csum = ICRS(c1.cartesian + c2.cartesian) csumrep = CartesianRepresentation(c1.cartesian.xyz + c2.cartesian.xyz) csum = ICRS(csumrep) npt.assert_allclose(csumrep.x.value, -8.12016610185) npt.assert_allclose(csumrep.y.value, 3.19380597435) npt.assert_allclose(csumrep.z.value, -8.2294483707) npt.assert_allclose(csum.ra.degree, 158.529401774) npt.assert_allclose(csum.dec.degree, -43.3235825777) npt.assert_allclose(csum.distance.kpc, 11.9942200501) @pytest.mark.skipif(str('not HAS_SCIPY')) def test_distances_scipy(): """ The distance-related tests that require scipy due to the cosmology module needing scipy integration routines """ from ...cosmology import WMAP5 #try different ways to initialize a Distance d4 = Distance(z=0.23) # uses default cosmology - as of writing, WMAP7 npt.assert_allclose(d4.z, 0.23, rtol=1e-8) d5 = Distance(z=0.23, cosmology=WMAP5) npt.assert_allclose(d5.compute_z(WMAP5), 0.23, rtol=1e-8) d6 = Distance(z=0.23, cosmology=WMAP5, unit=u.km) npt.assert_allclose(d6.value, 3.5417046898762366e+22) def test_distance_change(): ra = Longitude("4:08:15.162342", unit=u.hour) dec = Latitude("-41:08:15.162342", unit=u.degree) c1 = ICRS(ra, dec, Distance(1, unit=u.kpc)) oldx = c1.cartesian.x.value assert (oldx - 0.35284083171901953) < 1e-10 #first make sure distances are immutible with pytest.raises(AttributeError): c1.distance = Distance(2, unit=u.kpc) #now x should increase with a bigger distance increases c2 = ICRS(ra, dec, Distance(2, unit=u.kpc)) assert c2.cartesian.x.value == oldx * 2 def test_distance_is_quantity(): """ test that distance behaves like a proper quantity """ Distance(2 * u.kpc) d = Distance([2, 3.1], u.kpc) assert d.shape == (2,) a = d.view(np.ndarray) q = d.view(u.Quantity) a[0] = 1.2 q.value[1] = 5.4 assert d[0].value == 1.2 assert d[1].value == 5.4 q = u.Quantity(d, copy=True) q.value[1] = 0 assert q.value[1] == 0 assert d.value[1] != 0 # regression test against #2261 d = Distance([2 * u.kpc, 250. * u.pc]) assert d.unit is u.kpc assert np.all(d.value == np.array([2., 0.25])) def test_distmod(): d = Distance(10, u.pc) assert d.distmod.value == 0 d = Distance(distmod=20) assert d.distmod.value == 20 assert d.kpc == 100 d = Distance(distmod=-1., unit=u.au) npt.assert_allclose(d.value, 1301442.9440836983) with pytest.raises(ValueError): d = Distance(value=d, distmod=20) with pytest.raises(ValueError): d = Distance(z=.23, distmod=20) #check the Mpc/kpc/pc behavior assert Distance(distmod=1).unit == u.pc assert Distance(distmod=11).unit == u.kpc assert Distance(distmod=26).unit == u.Mpc assert Distance(distmod=-21).unit == u.AU #if an array, uses the mean of the log of the distances assert Distance(distmod=[1, 11, 26]).unit == u.kpc def test_distance_in_coordinates(): """ test that distances can be created from quantities and that cartesian representations come out right """ ra = Longitude("4:08:15.162342", unit=u.hour) dec = Latitude("-41:08:15.162342", unit=u.degree) coo = ICRS(ra, dec, distance=2*u.kpc) cart = coo.cartesian assert isinstance(cart.xyz, u.Quantity) def test_negative_distance(): """ Test optional kwarg allow_negative """ with pytest.raises(ValueError): Distance([-2, 3.1], u.kpc) with pytest.raises(ValueError): Distance([-2, -3.1], u.kpc) with pytest.raises(ValueError): Distance(-2, u.kpc) d = Distance(-2, u.kpc, allow_negative=True) assert d.value == -2 def test_distance_comparison(): """Ensure comparisons of distances work (#2206, #2250)""" a = Distance(15*u.kpc) b = Distance(15*u.kpc) assert a == b c = Distance(1.*u.Mpc) assert a < c def test_distance_to_quantity_when_not_units_of_length(): """Any operatation that leaves units other than those of length should turn a distance into a quantity (#2206, #2250)""" d = Distance(15*u.kpc) twice = 2.*d assert isinstance(twice, Distance) area = 4.*np.pi*d**2 assert area.unit.is_equivalent(u.m**2) assert not isinstance(area, Distance) assert type(area) is u.Quantity