Fixing C2v, adding stereographic plots for every point group, and making SYmmetry match ITOC standards

examples/stereographic_projection/plot_symmetry_operations.py

@@ -3,51 +3,44 @@
 Plot symmetry operations
 ========================
 
-This example shows how to draw proper symmetry operations :math:`s`
-(no reflections or inversions).
+This example shows how stereographic projections with symmetry operators can be
+automatically generated for the 32 crystallographic point groups.
+
+The ordering follows the one given in section 9.2 of "Structures of Materials"
+(DeGraef et.al, 2nd edition, 2012), starting with the cyclic groups, then the
+dihedral groups, then those same groups plus inversion centers, then the successive
+application of mirror planes and secondary rotational symmetries until all 32
+groups are made.
+
+The plots themselves as well as their labels follow the standards given in
+Table 10.2.2 of the "International Tables of Crystallography, Volume A" (ITOC).
+Both the nomenclature and marker styles thus differ slightly from some textbooks, as
+there are some arbitrary convention choices in both Schoenflies notation and marker
+styles.
+
+Orix uses Schoenflies Notation (left label above each plot) for variable names since
+they are short and always begin with a letter, but both Schoenflies and
+Hermann-Mauguin (right label above each plot) names can be used to look up symmetry
+groups using `PointGroups.get()`
 """
 
 import matplotlib.pyplot as plt
 
-from orix import plot
+import orix.plot
+from orix.quaternion.symmetry import PointGroups
 from orix.vector import Vector3d
 
-marker_size = 200
-fig, (ax0, ax1) = plt.subplots(
-    ncols=2,
-    subplot_kw={"projection": "stereographic"},
-    layout="tight",
-)
+# create a list of the 32 crystallographic point groups
+point_groups = PointGroups.get_set("procedural")
 
-ax0.set_title("432", pad=20)
-# 4-fold (outer markers will be clipped a bit...)
-v4fold = Vector3d([[0, 0, 1], [1, 0, 0], [-1, 0, 0], [0, 1, 0], [0, -1, 0]])
-ax0.symmetry_marker(v4fold, fold=4, c="C4", s=marker_size)
-ax0.draw_circle(v4fold, color="C4")
-# 3-fold
-v3fold = Vector3d([[1, 1, 1], [1, -1, 1], [-1, -1, 1], [-1, 1, 1]])
-ax0.symmetry_marker(v3fold, fold=3, c="C3", s=marker_size)
-ax0.draw_circle(v3fold, color="C3")
-# 2-fold
-# fmt: off
-v2fold = Vector3d(
-    [
-        [ 1,  0, 1],
-        [ 0,  1, 1],
-        [-1,  0, 1],
-        [ 0, -1, 1],
-        [ 1,  1, 0],
-        [-1, -1, 0],
-        [-1,  1, 0],
-        [ 1, -1, 0],
-    ]
+# prepare the plots
+fig, ax = plt.subplots(
+    4, 8, subplot_kw={"projection": "stereographic"}, figsize=[14, 10]
 )
-# fmt: on
-ax0.symmetry_marker(v2fold, fold=2, c="C2", s=marker_size)
-ax0.draw_circle(v2fold, color="C2")
-
-ax1.set_title("222", pad=20)
-# 2-fold
-v2fold = Vector3d([[0, 0, 1], [1, 0, 0], [-1, 0, 0], [0, 1, 0], [0, -1, 0]])
-ax1.symmetry_marker(v2fold, fold=2, c="C2", s=2 * marker_size)
-ax1.draw_circle(v2fold, color="C2")
+ax = ax.flatten()
+
+# create a vector to mirror over axes
+v = Vector3d.from_polar(65, 80, degrees=True)
+# Iterate through the 32 Point groups
+for i, pg in enumerate(point_groups):
+    pg.plot(asymetric_vector=v, plt_axis=ax[i], itoc_style=True)

orix/crystal_map/phase_list.py

@@ -31,12 +31,7 @@
 import matplotlib.colors as mcolors
 import numpy as np
 
-from orix.quaternion.symmetry import (
-    _EDAX_POINT_GROUP_ALIASES,
-    Symmetry,
-    _groups,
-    get_point_group,
-)
+from orix.quaternion.symmetry import _EDAX_POINT_GROUP_ALIASES, PointGroups, Symmetry
 from orix.vector import Miller, Vector3d
 
 # All named Matplotlib colors (tableau and xkcd already lower case hex)
@@ -232,21 +227,22 @@ def point_group(self) -> Symmetry | None:
             Point group.
         """
         if self.space_group is not None:
-            return get_point_group(self.space_group.number)
+            return PointGroups.from_space_group(self.space_group.number)
         else:
             return self._point_group
 
     @point_group.setter
     def point_group(self, value: int | str | Symmetry | None) -> None:
         """Set the point group."""
+        groups = PointGroups._pg_sets["permutations_repeated"]
         if isinstance(value, int):
             value = str(value)
         if isinstance(value, str):
             for key, aliases in _EDAX_POINT_GROUP_ALIASES.items():
                 if value in aliases:
                     value = key
                     break
-            for point_group in _groups:
+            for point_group in groups:
                 if value == point_group.name:
                     value = point_group
                     break