Previewing xdmf file

Question

I am solving a time dependant pde and I save the solution at each time step.

u_file = XDMFFile("velocity.xdmf")

while t < T:
     t += dt
     # solve for u
     u_file << u

This while loop takes a long time to finish. I want to check if 'u' is making sense so far. Hence, so way to preview 'velocity.xdmf' would be very useful but it cannot be read by paraview until the program terminates.

Answer 1

Try setting the parameter

u_file.parameters["flush_output"] = True

Comments

On a different note, for time-dependent problems where the mesh does not change, I also advise setting

u_file.parameters["rewrite_function_mesh"] = False

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For reference, see the related Issue https://bitbucket.org/fenics-project/dolfin/issue/278