Ordering of 3D solution vector

I’m dealing with the 3d Elastodynamics problem in the examples, where we have a 3D displacement vector field. Obvioulsly, if we have N points in the mesh, then the solution vector u will be of length 3N.
My question is about the ordering in the following solution vector accessed via:


my guess is that the vector is ordered as uh = [uh_x, uh_y, uh_z], where each uh_x is of length N. So that if we access the i-th item in the coordinates array, then the associated solution vector shoud be [uh_x[i], uh_y[i], uh_z[i]], is that reasonable?