def test_HklPlane_normal(self):
ZrO2 = Lattice.tetragonal(3.64, 5.27)
p = HklPlane(1, 1, 1, ZrO2)
n = p.normal()
self.assertAlmostEqual(n[0], 0.635, 3)
self.assertAlmostEqual(n[1], 0.635, 3)
self.assertAlmostEqual(n[2], 0.439, 3)
def test_gnomonic_projection_point(self):
"""Verify that the gnomonic projection of two diffracted points on a detector give access to the angle
between the lattice plane normals."""
olivine = Lattice.orthorhombic(
1.022, 0.596, 0.481) # nm Barret & Massalski convention
orientation = Orientation.cube()
p1 = HklPlane(2, 0, -3, olivine)
p2 = HklPlane(3, -1, -3, olivine)
detector = RegArrayDetector2d(size=(512, 512),
u_dir=[0, -1, 0],
v_dir=[0, 0, -1])
detector.pixel_size = 0.200 # mm, 0.1 mm with factor 2 binning
detector.ucen = 235
detector.vcen = 297
detector.ref_pos = np.array([131., 0., 0.]) + \
(detector.size[0] / 2 - detector.ucen) * detector.u_dir * detector.pixel_size + \
(detector.size[1] / 2 - detector.vcen) * detector.v_dir * detector.pixel_size # mm
angle = 180 / np.pi * np.arccos(np.dot(p1.normal(), p2.normal()))
# test the gnomonic projection for normal and not normal X-ray incidence
for ksi in [0.0, 1.0]: # deg
Xu = np.array(
[np.cos(ksi * np.pi / 180), 0.,
np.sin(ksi * np.pi / 180)])
OC = detector.project_along_direction(
Xu
) # C is the intersection of the direct beam with the detector
K1 = diffracted_vector(p1, orientation, Xu=Xu)
K2 = diffracted_vector(p2, orientation, Xu=Xu)
R1 = detector.project_along_direction(K1, origin=[0., 0., 0.])
R2 = detector.project_along_direction(K2, origin=[0., 0., 0.])
OP1 = gnomonic_projection_point(R1, OC=OC)[0]
OP2 = gnomonic_projection_point(R2, OC=OC)[0]
hkl_normal1 = OP1 / np.linalg.norm(OP1)
hkl_normal2 = (OP2 / np.linalg.norm(OP2))
# the projection must give the normal to the diffracting plane
for i in range(3):
self.assertAlmostEqual(hkl_normal1[i], p1.normal()[i], 6)
self.assertAlmostEqual(hkl_normal2[i], p2.normal()[i], 6)
angle_gp = 180 / np.pi * np.arccos(np.dot(hkl_normal1,
hkl_normal2))
self.assertAlmostEqual(angle, angle_gp, 6)
def plot_sst(self, ax=None, mk='s', ann=False):
""" Create the inverse pole figure in the unit standard triangle.
:param ax: a reference to a pyplot ax to draw the poles.
:param mk: marker used to plot the poles (square by default).
:param bool ann: Annotate the pole with the coordinates of the vector if True (False by default).
"""
# first draw the boundary of the symmetry domain limited by 3 hkl plane normals, called here A, B and C
symmetry = self.lattice._symmetry
if symmetry is Symmetry.cubic:
sst_poles = [(0, 0, 1), (1, 0, 1), (1, 1, 1)]
ax.axis([-0.05, 0.45, -0.05, 0.40])
elif symmetry is Symmetry.hexagonal:
sst_poles = [(0, 0, 1), (2, -1, 0), (1, 0, 0)]
ax.axis([-0.05, 1.05, -0.05, 0.6])
else:
print('unssuported symmetry: %s' % symmetry)
A = HklPlane(*sst_poles[0], lattice=self.lattice)
B = HklPlane(*sst_poles[1], lattice=self.lattice)
C = HklPlane(*sst_poles[2], lattice=self.lattice)
self.plot_line_between_crystal_dir(A.normal(),
B.normal(),
ax=ax,
col='k')
self.plot_line_between_crystal_dir(B.normal(),
C.normal(),
ax=ax,
col='k')
self.plot_line_between_crystal_dir(C.normal(),
A.normal(),
ax=ax,
col='k')
# display the 3 crystal axes
poles = [A, B, C]
v_align = ['top', 'top', 'bottom']
for i in range(3):
hkl = poles[i]
c_dir = hkl.normal()
c = c_dir + self.z
c /= c[2] # SP'/SP = r/z with r=1
pole_str = '%d%d%d' % hkl.miller_indices()
if symmetry is Symmetry.hexagonal:
pole_str = '%d%d%d%d' % HklPlane.three_to_four_indices(
*hkl.miller_indices())
ax.annotate(pole_str, (c[0], c[1] - (2 * (i < 2) - 1) * 0.01),
xycoords='data',
fontsize=12,
horizontalalignment='center',
verticalalignment=v_align[i])
# now plot the sample axis
for grain in self.microstructure.grains:
# move to the fundamental zone
g = grain.orientation_matrix()
# compute axis and apply SST symmetry
if self.axis == 'Z':
axis = self.z
elif self.axis == 'Y':
axis = self.y
else:
axis = self.x
axis_rot = self.sst_symmetry(g.dot(axis))
label = ''
if self.map_field == 'grain_id':
label = 'grain ' + str(grain.id)
self.plot_crystal_dir(axis_rot,
mk=mk,
col=self.get_color_from_field(grain),
ax=ax,
ann=ann,
lab=label)
if self.verbose:
print('plotting %s in crystal CS: %s' % (self.axis, axis_rot))
ax.axis('off')
ax.set_title('%s-axis SST inverse %s projection' %
(self.axis, self.proj))
def test_HklPlane(self):
p = HklPlane(1, 1, 1)
n = p.normal()
self.assertEqual(np.linalg.norm(n), 1)
