Get rid of dependency on Moble's quaternions.

Former-commit-id: 182aeda66992aa43c2c172c28a199feba0d6878f

TODO.md

@@ -7,6 +7,8 @@ TODO list before public release
 - Field calculations.
 - Complex frequencies, n's, k's.
 - Transforming point (meta)generators.
+- Check whether moble's quaternions and my 
+  quaternions give the same results in tmatrices.py
 - Ewald summations of all types of lattices (dimensionality-wise).
 - Split lattices.h into separate point generator and lattice vector manipulation parts.
   * Maybe move something from the .h to .c file.

qpms/qpms_c.pyx

@@ -920,6 +920,18 @@ cdef class CQuat:
             return 0
         return qpms_wignerD_elem(self.q, l, mp, m)
     
+    @staticmethod
+    def from_rotvector(vec):
+        if vec.shape != (3,):
+            raise ValueError("Single 3d vector expected")
+        res = CQuat()
+        cdef cart3_t v
+        v.x = vec[0]
+        v.y = vec[1]
+        v.z = vec[2]
+        res.q = qpms_quat_from_rotvector(v)
+        return res
+
 cdef class IRot3:
     '''
     Wrapper over the C type qpms_irot3_t.

qpms/qpms_cdefs.pxd

@@ -188,6 +188,7 @@ cdef extern from "wigner.h":
                            qpms_m_t mp, qpms_m_t m)
     qpms_irot3_t qpms_irot3_mult(qpms_irot3_t p, qpms_irot3_t q)
     qpms_irot3_t qpms_irot3_pow(qpms_irot3_t p, int n)
+    qpms_quat_t qpms_quat_from_rotvector(cart3_t v)
 
 cdef extern from "groups.h":
     struct qpms_finite_group_irrep_t:

qpms/tmatrices.py

@@ -1,9 +1,15 @@
 import numpy as np
-import quaternion, spherical_functions as sf # because of the Wigner matrices. These imports are SLOW.
+use_moble_quaternion = False
+try:
+    import quaternion, spherical_functions as sf # because of the Wigner matrices. These imports are SLOW.
+    use_moble_quaternion = True
+except ImportError:
+    use_moble_quaternion = False
+
 import re
 from scipy import interpolate
 from scipy.constants import hbar, e as eV, pi, c
-from qpms_c import get_mn_y, get_nelem
+from qpms_c import get_mn_y, get_nelem, CQuat
 ň = np.newaxis
 from .types import NormalizationT, TMatrixSpec
 
@@ -17,15 +23,26 @@ def WignerD_mm(l, quat):
     TODO doc
     """
     
-    indices = np.array([ [l,i,j] for i in range(-l,l+1) for j in range(-l,l+1)])
-    Delems = sf.Wigner_D_element(quat, indices).reshape(2*l+1,2*l+1)
-    return Delems
+    if use_moble_quaternion:
+        indices = np.array([ [l,i,j] for i in range(-l,l+1) for j in range(-l,l+1)])
+        Delems = sf.Wigner_D_element(quat, indices).reshape(2*l+1,2*l+1)
+        return Delems
+    else:
+        Delems = np.zeros((2*l+1, 2*l+1), dtype=complex)
+        for i in range(-l,l+1):
+            for j in range(-l,l+1):
+                Delems[i,j] = quat.wignerDelem(l, i, j)
+        return Delems
+
 
 def WignerD_mm_fromvector(l, vect):
     """
     TODO doc
     """
-    return WignerD_mm(l, quaternion.from_rotation_vector(vect))
+    if use_moble_quaternion:
+        return WignerD_mm(l, quaternion.from_rotation_vector(vect))
+    else:
+        return WignerD_mm(l, CQuat.from_rotvector(vect))
 
 
 def WignerD_yy(lmax, quat):
@@ -46,7 +63,10 @@ def WignerD_yy_fromvector(lmax, vect):
     """
     TODO doc
     """
-    return WignerD_yy(lmax, quaternion.from_rotation_vector(vect))
+    if use_moble_quaternion:
+        return WignerD_yy(lmax, quaternion.from_rotation_vector(vect))
+    else:
+        return WignerD_yy(lMax, CQuat.from_rotvector(vect))
 
 def identity_yy(lmax):
     """

qpms/wigner.h

@@ -113,6 +113,7 @@ static inline qpms_quat_t qpms_quat_pow(const qpms_quat_t q, const double expone
 	return qpms_quat_exp(qe);
 }
 
+
 /// Quaternion inversion.
 /** \f[ q^{-1} = \frac{q*}{|q|}. \f] */
 static inline qpms_quat_t qpms_quat_inv(const qpms_quat_t q) {
@@ -144,6 +145,12 @@ static inline cart3_t qpms_quat_rot_cart3(qpms_quat_t q, const cart3_t v) {
 				qpms_quat_mult(vv, qc)));
 }
 
+/// Versor quaternion from rotation vector (norm of the vector is the rotation angle).
+static inline qpms_quat_t qpms_quat_from_rotvector(cart3_t v) {
+        return qpms_quat_exp(qpms_quat_rscale(0.5,
+				qpms_quat_from_cart3(v)));
+}
+
 /// Wigner D matrix element from a rotator quaternion for integer \a l.
 /**
  * The D matrix are calculated using formulae (3), (4), (6), (7) from

setup.py

@@ -98,8 +98,10 @@ setup(name='qpms',
         packages=['qpms'],
 #        libraries = [('amos', {'sources': amos_sources} )],
         setup_requires=['cython>=0.28',],
-        install_requires=['cython>=0.28','quaternion','spherical_functions','scipy>=0.18.0', 'sympy>=1.2'],
-        dependency_links=['https://github.com/moble/quaternion/archive/v2.0.tar.gz','https://github.com/moble/spherical_functions/archive/master.zip'],
+        install_requires=['cython>=0.28',
+            #'quaternion','spherical_functions',
+            'scipy>=0.18.0', 'sympy>=1.2'],
+        #dependency_links=['https://github.com/moble/quaternion/archive/v2.0.tar.gz','https://github.com/moble/spherical_functions/archive/master.zip'],
         ext_modules=cythonize([qpms_c], include_path=['qpms', 'amos'], gdb_debug=True),
         cmdclass = {'build_ext': build_ext},
         )