dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

The unit test currently failing on the Mac buildbot (timing out) is
failing on my machine (Ubuntu 11.10) with a PETSc error claiming that
the vector in question is not ghosted.

I've tracked it down to the plotting from the C++ eigenvalue demo, and
the call to gather() from within interpolate_vertex_values.

The problem is that the Function to be plotted is created from a
solution vector x from the eigenvalue problem like so:

  Function u(V, x);

Since x does not come from a Function to begin with, it was not
initialized with ghost values, so then later when
u.interpolated_vertex_values is called, the call to gather() fails.

Should there be a test for whether ghost values exist in either
PETScVector or Function (_have_ghost_values)?

On top of this, the call to plot() does not work in parallel from C++
anyway so it's easy to make the bug disappear (by moving the check in
the plot function earlier to before the call to
interpolate_vertex_values), but it exposes a problem with the
constructor

  Function u(V, x);

which may not make sense if x does not have the proper layout.

--
Anders