Modifying PeriodicBoundary3 class to be periodic in x, y, z

Question

Hello,
I have been using the following DOLFIN class (which I found at https://bitbucket.org/fenics-project/dolfin/pull-requests/4/adding-test-for/diff) to allow my 3D meshes (e.g. a cube mesh) to be periodic in the x direction.

class PeriodicBoundary3(SubDomain):
    def inside(self, x, on_boundary):
        return bool(x[0] < DOLFIN_EPS and x[0] > -DOLFIN_EPS and on_boundary)

    def map(self, x, y):
        y[0] = x[0] - 1.0
        y[1] = x[1]
        y[2] = x[2]

I would like to know how to modify this class to make my mesh periodic in all three directions (x, y and z).
Thank you in advance for your help!

Comments

You may find this answer to an old question useful.

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That's great - thank you!