test for deflect() function

glass/test/test_lensing.py

@@ -0,0 +1,55 @@
+import numpy as np
+import numpy.testing as npt
+import pytest
+
+
+@pytest.mark.parametrize("usecomplex", [True, False])
+def test_deflect_nsew(usecomplex):
+    from glass.lensing import deflect
+
+    d = 5.
+    r = np.radians(d)
+
+    if usecomplex:
+        def alpha(re, im):
+            return re + 1j*im
+    else:
+        def alpha(re, im):
+            return [re, im]
+
+    # north
+    lon, lat = deflect(0., 0., alpha(r, 0))
+    assert np.allclose([lon, lat], [0., d])
+
+    # south
+    lon, lat = deflect(0., 0., alpha(-r, 0))
+    assert np.allclose([lon, lat], [0., -d])
+
+    # east
+    lon, lat = deflect(0., 0., alpha(0, r))
+    assert np.allclose([lon, lat], [-d, 0.])
+
+    # west
+    lon, lat = deflect(0., 0., alpha(0, -r))
+    assert np.allclose([lon, lat], [d, 0.])
+
+
+def test_deflect_many():
+    import healpix
+    from glass.lensing import deflect
+
+    n = 1000
+    abs_alpha = np.random.uniform(0, 2*np.pi, size=n)
+    arg_alpha = np.random.uniform(-np.pi, np.pi, size=n)
+
+    lon_ = np.degrees(np.random.uniform(-np.pi, np.pi, size=n))
+    lat_ = np.degrees(np.arcsin(np.random.uniform(-1, 1, size=n)))
+
+    lon, lat = deflect(lon_, lat_, abs_alpha*np.exp(1j*arg_alpha))
+
+    x_, y_, z_ = healpix.ang2vec(lon_, lat_, lonlat=True)
+    x, y, z = healpix.ang2vec(lon, lat, lonlat=True)
+
+    dotp = x*x_ + y*y_ + z*z_
+
+    npt.assert_allclose(dotp, np.cos(abs_alpha))