yuanpeng / uniform_move_snippet

! For the polar angle part, since projection is involved and therefore ! we need to guarantee that the projection is uniform. We don't need ! to do this for the phi angle since only rotation is involved in ! that case. polar_ang = dacos(2.0d0*(rmca_ran(1)-0.5d0)) azim_ang = rmca_ran(1) * 2.0d0 * pi rand_x = delta(move_type) * dsin(polar_ang) * dcos(azim_ang) rand_y = delta(move_type) * dsin(polar_ang) * dsin(azim_ang) rand_z = delta(move_type) * dcos(polar_ang) ! We go from the Cartesian coordinates to fractional with respect ! to the lattice. move(4) = rand_x * inv_vectors_init(1,1) + & rand_y * inv_vectors_init(1,2) + & rand_z * inv_vectors_init(1,3) move(5) = rand_x * inv_vectors_init(2,1) + & rand_y * inv_vectors_init(2,2) + & rand_z * inv_vectors_init(2,3) move(6) = rand_x * inv_vectors_init(3,1) + & rand_y * inv_vectors_init(3,2) + & rand_z * inv_vectors_init(3,3)