Improve test of sampling rotations taking Z-vector to fundamental sector

Signed-off-by: Håkon Wiik Ånes <[email protected]>

orix/tests/sampling/test_sampling.py

@@ -20,7 +20,7 @@
 import pytest
 
 from orix.quaternion import Rotation
-from orix.quaternion.symmetry import C2, C4, C6, D6, get_point_group
+from orix.quaternion.symmetry import C2, C4, C6, D6, Oh, get_point_group
 from orix.sampling import (
     get_sample_fundamental,
     get_sample_local,
@@ -34,6 +34,7 @@
     _get_max_grid_angle,
     _get_start_and_end_index,
 )
+from orix.vector import Vector3d
 
 
 @pytest.fixture(scope="session")
@@ -182,17 +183,34 @@ def test_get_sample_fundamental_space_group(self, C6_sample):
         assert np.isclose(ratio, 3, atol=0.2)
 
     def test_get_sample_reduced_fundamental(self):
-        rotations = get_sample_reduced_fundamental(resolution=4)
-        rotations2 = get_sample_reduced_fundamental(resolution=4, point_group=C2)
-        rotations4 = get_sample_reduced_fundamental(resolution=4, point_group=C4)
-        rotations6 = get_sample_reduced_fundamental(resolution=4, point_group=C4)
-
-        assert (
-            np.abs(rotations.size / rotations2.size) - 2 < 0.1
-        )  # about 2 times more rotations
-        assert (
-            np.abs(rotations2.size / rotations4.size) - 2 < 0.1
-        )  # about 2 times more rotations
-        assert (
-            np.abs(rotations.size / rotations6.size) - 6 < 0.1
-        )  # about 6 times more rotations
+        vz = Vector3d.zvector()
+
+        R_C1 = get_sample_reduced_fundamental(resolution=4)
+        v_C1 = R_C1 * vz
+        assert np.allclose(v_C1.mean().data, [0, 0, 0])
+
+        R_C4 = get_sample_reduced_fundamental(resolution=4, point_group=C4)
+        v_C4 = R_C4 * vz
+        assert np.all(v_C4 <= C4.fundamental_sector)
+
+        R_C6 = get_sample_reduced_fundamental(resolution=4, point_group=C6)
+        v_C6 = R_C6 * vz
+        assert np.all(v_C6 <= C6.fundamental_sector)
+
+        R_Oh = get_sample_reduced_fundamental(point_group=Oh)
+        v_Oh = R_Oh * vz
+        assert np.all(v_Oh <= Oh.fundamental_sector)
+
+        # Some rotations have a phi1 Euler angle of multiples of pi,
+        # presumably due to rounding errors
+        phi1_C1 = R_C1.to_euler()[:, 0].round(7)
+        assert np.allclose(np.unique(phi1_C1), [0, 2 * np.pi], atol=1e-7)
+        phi1_C4 = R_C4.to_euler()[:, 0].round(7)
+        assert np.allclose(np.unique(phi1_C4), [0, np.pi / 2], atol=1e-7)
+        phi1_C6 = R_C6.to_euler()[:, 0].round(7)
+        assert np.allclose(np.unique(phi1_C6), [0, np.pi / 2], atol=1e-7)
+        phi1_Oh = R_Oh.to_euler()[:, 0].round(7)
+        assert np.allclose(np.unique(phi1_Oh), [0, np.pi / 2], atol=1e-7)
+
+        R_Oh2 = get_sample_reduced_fundamental(point_group=Oh, method="icosahedral")
+        assert R_Oh.size > R_Oh2.size