def fractional_from_cartesian(coordinate, lattice_array):
deorthogonalisation_M = np.matrix(np.linalg.inv(lattice_array))<EOL>fractional = deorthogonalisation_M * coordinate.reshape(-<NUM_LIT:1>, <NUM_LIT:1>)<EOL>return np.array(fractional.reshape(<NUM_LIT:1>, -<NUM_LIT:1>))<EOL>
Return a fractional coordinate from a cartesian one.