def run_correlation_matrix(self, T):
"""Calculate displacement-displacement correlation matrix."""
qpoints, eigvals, eigvecs = self._collect_eigensolutions()
d2f = DynmatToForceConstants(self._dynmat.primitive,
self._dynmat.supercell)
masses = self._dynmat.supercell.masses
d2f.commensurate_points = qpoints
freqs = np.sqrt(np.abs(eigvals)) * self._factor
conditions = freqs > self._cutoff_frequency
a = self._get_sigma(eigvals, T)
a2 = a**2
_a = np.where(conditions, a, 1)
a2_inv = np.where(conditions, 1 / _a**2, 0)
d2f.create_dynamical_matrices(a2_inv, eigvecs)
d2f.run()
self._uu_inv = np.array(d2f.force_constants, dtype="double", order="C")
d2f.create_dynamical_matrices(a2, eigvecs)
d2f.run()
matrix = d2f.force_constants
for i, m_i in enumerate(masses):
for j, m_j in enumerate(masses):
matrix[i, j] /= m_i * m_j
self._uu = np.array(matrix, dtype="double", order="C")
def run_d2f(self):
qpoints, eigvals, eigvecs = self._collect_eigensolutions()
d2f = DynmatToForceConstants(self._dynmat.primitive,
self._dynmat.supercell)
d2f.commensurate_points = qpoints
d2f.create_dynamical_matrices(eigvals, eigvecs)
d2f.run()
self._force_constants = d2f.force_constants
