utility function without connection to an object

python/damask/_orientation.py

@@ -666,10 +666,10 @@ class Orientation(Rotation):
         o = r[ol]
 
         p_,_p = np.zeros(m.shape[:-1]+(3,)),np.zeros(o.shape[:-1]+(3,))
-        p_[...,0,:] = m[...,0,:] if m.shape[-1] == 3 else lattice_.Bravais_to_Miller(uvtw=m[...,0,0:4])
+        p_[...,0,:] = m[...,0,:] if m.shape[-1] == 3 else util.Bravais_to_Miller(uvtw=m[...,0,0:4])
-        p_[...,1,:] = m[...,1,:] if m.shape[-1] == 3 else lattice_.Bravais_to_Miller(hkil=m[...,1,0:4])
+        p_[...,1,:] = m[...,1,:] if m.shape[-1] == 3 else util.Bravais_to_Miller(hkil=m[...,1,0:4])
-        _p[...,0,:] = o[...,0,:] if o.shape[-1] == 3 else lattice_.Bravais_to_Miller(uvtw=o[...,0,0:4])
+        _p[...,0,:] = o[...,0,:] if o.shape[-1] == 3 else util.Bravais_to_Miller(uvtw=o[...,0,0:4])
-        _p[...,1,:] = o[...,1,:] if o.shape[-1] == 3 else lattice_.Bravais_to_Miller(hkil=o[...,1,0:4])
+        _p[...,1,:] = o[...,1,:] if o.shape[-1] == 3 else util.Bravais_to_Miller(hkil=o[...,1,0:4])
 
         return (Rotation.from_parallel(p_,_p),ol) \
                 if return_lattice else \
@@ -1254,8 +1254,8 @@ class Orientation(Rotation):
             master = lattice_.kinematics[self.lattice][mode]
             kinematics = {'direction':master[:,0:3],'plane':master[:,3:6]} \
                           if master.shape[-1] == 6 else \
-                         {'direction':lattice_.Bravais_to_Miller(uvtw=master[:,0:4]),
+                         {'direction':util.Bravais_to_Miller(uvtw=master[:,0:4]),
-                          'plane':    lattice_.Bravais_to_Miller(hkil=master[:,4:8])}
+                          'plane':    util.Bravais_to_Miller(hkil=master[:,4:8])}
         except KeyError:
             raise (f'"{mode}" not defined for lattice "{self.lattice}"')
         d = self.to_frame(uvw=kinematics['direction'],with_symmetry=False)

python/damask/util.py

@@ -27,6 +27,7 @@ __all__=[
          'execution_stamp',
          'shapeshifter', 'shapeblender',
          'extend_docstring', 'extended_docstring',
+         'Bravais_to_Miller', 'Miller_to_Bravais',
          'DREAM3D_base_group', 'DREAM3D_cell_data_group',
          'dict_prune', 'dict_flatten'
         ]
@@ -499,6 +500,62 @@ def DREAM3D_cell_data_group(fname):
     return cell_data_group
 
 
+def Bravais_to_Miller(*,uvtw=None,hkil=None):
+    """
+    Transform 4 Miller–Bravais indices to 3 Miller indices of crystal direction [uvw] or plane normal (hkl).
+
+    Parameters
+    ----------
+    uvtw|hkil : numpy.ndarray of shape (...,4)
+        Miller–Bravais indices of crystallographic direction [uvtw] or plane normal (hkil).
+
+    Returns
+    -------
+    uvw|hkl : numpy.ndarray of shape (...,3)
+        Miller indices of [uvw] direction or (hkl) plane normal.
+
+    """
+    if (uvtw is not None) ^ (hkil is None):
+        raise KeyError('Specify either "uvtw" or "hkil"')
+    axis,basis  = (np.array(uvtw),np.array([[1,0,-1,0],
+                                            [0,1,-1,0],
+                                            [0,0, 0,1]])) \
+                  if hkil is None else \
+                  (np.array(hkil),np.array([[1,0,0,0],
+                                            [0,1,0,0],
+                                            [0,0,0,1]]))
+    return np.einsum('il,...l',basis,axis)
+
+
+def Miller_to_Bravais(*,uvw=None,hkl=None):
+    """
+    Transform 3 Miller indices to 4 Miller–Bravais indices of crystal direction [uvtw] or plane normal (hkil).
+
+    Parameters
+    ----------
+    uvw|hkl : numpy.ndarray of shape (...,3)
+        Miller indices of crystallographic direction [uvw] or plane normal (hkl).
+
+    Returns
+    -------
+    uvtw|hkil : numpy.ndarray of shape (...,4)
+        Miller–Bravais indices of [uvtw] direction or (hkil) plane normal.
+
+    """
+    if (uvw is not None) ^ (hkl is None):
+        raise KeyError('Specify either "uvw" or "hkl"')
+    axis,basis  = (np.array(uvw),np.array([[ 2,-1, 0],
+                                           [-1, 2, 0],
+                                           [-1,-1, 0],
+                                           [ 0, 0, 3]])/3) \
+                  if hkl is None else \
+                  (np.array(hkl),np.array([[ 1, 0, 0],
+                                           [ 0, 1, 0],
+                                           [-1,-1, 0],
+                                           [ 0, 0, 1]]))
+    return np.einsum('il,...l',basis,axis)
+
+
 def dict_prune(d):
     """
     Recursively remove empty dictionaries.

python/tests/test_Orientation.py

@@ -484,6 +484,7 @@ class TestOrientation:
         assert np.allclose(vector,
                            L.to_frame(**{keyFrame:L.to_lattice(**{keyLattice:vector})}))
 
+
     @pytest.mark.parametrize('lattice,a,b,c,alpha,beta,gamma',
                             [
                              ('aP',0.5,2.0,3.0,0.8,0.5,1.2),

python/tests/test_lattice.py

@@ -1,34 +0,0 @@
-import pytest
-import numpy as np
-
-from damask import lattice
-
-class TestLattice:
-
-    def test_double_Bravais_to_Miller(self):
-        with pytest.raises(KeyError):
-            lattice.Bravais_to_Miller(uvtw=np.ones(4),hkil=np.ones(4))                              # noqa
-
-    def test_double_Miller_to_Bravais(self):
-        with pytest.raises(KeyError):
-            lattice.Miller_to_Bravais(uvw=np.ones(4),hkl=np.ones(4))                                # noqa
-
-    @pytest.mark.parametrize('vector',np.array([
-                                                [1,0,0],
-                                                [1,1,0],
-                                                [1,1,1],
-                                                [1,0,-2],
-                                               ]))
-    @pytest.mark.parametrize('kw_Miller,kw_Bravais',[('uvw','uvtw'),('hkl','hkil')])
-    def test_Miller_Bravais_Miller(self,vector,kw_Miller,kw_Bravais):
-        assert np.all(vector == lattice.Bravais_to_Miller(**{kw_Bravais:lattice.Miller_to_Bravais(**{kw_Miller:vector})}))
-
-    @pytest.mark.parametrize('vector',np.array([
-                                                [1,0,-1,2],
-                                                [1,-1,0,3],
-                                                [1,1,-2,-3],
-                                                [0,0,0,1],
-                                               ]))
-    @pytest.mark.parametrize('kw_Miller,kw_Bravais',[('uvw','uvtw'),('hkl','hkil')])
-    def test_Bravais_Miller_Bravais(self,vector,kw_Miller,kw_Bravais):
-        assert np.all(vector == lattice.Miller_to_Bravais(**{kw_Miller:lattice.Bravais_to_Miller(**{kw_Bravais:vector})}))

python/tests/test_util.py

@@ -158,3 +158,33 @@ class TestUtil:
                                              ({'A':{'B':{},'C':'D'}},       {'B':{},'C':'D'})])
     def test_flatten(self,full,reduced):
         assert util.dict_flatten(full) == reduced
+
+
+    def test_double_Bravais_to_Miller(self):
+        with pytest.raises(KeyError):
+            util.Bravais_to_Miller(uvtw=np.ones(4),hkil=np.ones(4))
+
+    def test_double_Miller_to_Bravais(self):
+        with pytest.raises(KeyError):
+            util.Miller_to_Bravais(uvw=np.ones(4),hkl=np.ones(4))
+
+
+    @pytest.mark.parametrize('vector',np.array([
+                                                [1,0,0],
+                                                [1,1,0],
+                                                [1,1,1],
+                                                [1,0,-2],
+                                               ]))
+    @pytest.mark.parametrize('kw_Miller,kw_Bravais',[('uvw','uvtw'),('hkl','hkil')])
+    def test_Miller_Bravais_Miller(self,vector,kw_Miller,kw_Bravais):
+        assert np.all(vector == util.Bravais_to_Miller(**{kw_Bravais:util.Miller_to_Bravais(**{kw_Miller:vector})}))
+
+    @pytest.mark.parametrize('vector',np.array([
+                                                [1,0,-1,2],
+                                                [1,-1,0,3],
+                                                [1,1,-2,-3],
+                                                [0,0,0,1],
+                                               ]))
+    @pytest.mark.parametrize('kw_Miller,kw_Bravais',[('uvw','uvtw'),('hkl','hkil')])
+    def test_Bravais_Miller_Bravais(self,vector,kw_Miller,kw_Bravais):
+        assert np.all(vector == util.Miller_to_Bravais(**{kw_Miller:util.Bravais_to_Miller(**{kw_Bravais:vector})}))