Dear Floriane,


Don't use .vector() if you want to treat different coordinates differently. Try something like this:


mesh.coordinates.dat.data[:, 0] *= (L-R)/L

mesh.coordinates.dat.data[:, 0] += R


Regards,

Miklos

From: firedrake-bounces@imperial.ac.uk <firedrake-bounces@imperial.ac.uk> on behalf of Floriane Gidel [RPG] <mmfg@leeds.ac.uk>
Sent: 05 August 2016 08:50:47
To: firedrake
Subject: [firedrake] Changing coordinates in one direction only
 

Dear all,

I use a change of coordinate to solve my equations, and I then save the solutions in the initial domain. 
The transform is \hat{x} = L(x-R)/(L-R).

In 1D, my code to save the data in the initial (not transformed) mesh is:

----------------------------
# mesh on which I solve the equations (\hat{x})
mesh_transformed = mesh.coordinates.vector().get_local()  

# back to the initial mesh (applying the inverse transform) (x)

mesh.coordinates.vector().set_local(mesh_transformed*(L-R)/L + R)


# save data on the initial mesh
save_h << h
save_psi << psi

# Back to the transformed mesh to solve the WF (\hat{x})

mesh.coordinates.vector().set_local(mesh_transformed)

----------------------------

This works well in 1D. However, I would like to extend my model in 2D, where the transform is still only in x. Therefore, I would like to apply the previous manipulation to the x coordinate only, and not on the 2D mesh. The previous code changes both x and y. 
How can I change only x ?

Thanks,
Floriane